MIGRATION AND WINTERING ECOLOGY

OF THE ALEUTIAN CANADA GOOSE

by

Dennis W. Woolington

A Thesis

Presented to

The Faculty of Humboldt State University

In Partial Fulfillment

of the Requirements for the Degree

Master of Science

June, 1980 MIGRATION AND WINTERING ECOLOGY

OF THE ALEUTIAN CANADA GOOSE

by

Dennis W. Woolington

Approved by the Master's Thesis Committee

Paul F. Springer, Chairman

Stanley W. Harks

Natural Resources Graduate Program

Approved by the Dean of Graduate StudiesAlba

Alba M. Gillespie ABSTRACT

A study to determine the migration and wintering ground distri­ bution, ecology, and population status of the endangered Aleutian Canada goose (Branta canadensis leucopareia) was conducted from October 1975 to

May 1978. Field investigations extended from the western Aleutian

Islands, Alaska, to the. Central Valley of California. Prior to and during the study, 536 Aleutian geese were banded to document movement and survival.

It was determined that the geese use traditional migration and wintering areas away from Alaska, returning to virtually the same fields annually. During September, Aleutian Canada geese migrate along the

Aleutian Island chain from Buldir Island near the western end to the easternmost island of Unimak and then apparently shift southeast on a transoceanic flight. The geese arrive in California in early October; some stop near Crescent City, but most birds continue to the Sacramento

Valley where over 95 percent of the population uses a small agricultural area in the Butte Sink. From mid-November to early December the geese move southward via the Sacramento-San Joaquin River Delta to the grass­ lands of the upper San Joaquin Valley. Most of the birds are present as a single flock near Modesto from at least late December to early

February. They begin shifting southward to an area near Los Banos in mid-January, and some are present until mid-March. Aleutian geese start moving northward to the Crescent City staging grounds as early as mid-

January, with most of the birds arriving during March. They peak in number there in late March and early April when nearly the entire known iv

population is present. In mid-April, geese begin to leave Crescent City

to the breeding grounds, and by late April or early May all have left.

Although a few Aleutian Canada geese have been reported near the mouth of the Columbia River, Washington, most apparently make a transoceanic flight to the eastern Aleutians. There, they continue westward to

Buldir where they have been seen as early as the first week of May.

During the study, hunting and avian cholera were found to be the main sources of winter mortality. Closure on Canada goose hunting en­ acted in three areas of California at the onset of the study has reduced mortality from an estimated preclosure rate of 22.5 percent annually to approximately 11.5 percent during winters 1975-76 and 1976-77. This winter mortality may comprise the majority of the annual loss. The spring population increased 45.6 percent, from 790 in April 1975 to 1150 in March 1977. Management needs on the migration and wintering grounds include continuation of protection of the geese through hunting closures and maintenance of suitable habitat conditions on their major use areas. ACKNOWLEDGEMENTS

This study was funded by the U. S. Fish and Wildlife Service through a contract with Humboldt State University. Funds, equipment, and vehicles were provided by the U. S. Fish and Wildlife Service through the Endangered Species and Migratory Bird Programs.

I would like to thank all the members of my committee for their time and assistance. Committee chairman and study supervisor Dr. Paul

F. Springer of the Wildlife Research Field Station, U. S. Fish and Wild­ life Service, provided support, encouragement, and field assistance throughout both the data collection and thesis preparation phases of this study. Dr. Stanley W. Harris and Dr. John 0. Sawyer of Humboldt

State University critically reviewed this thesis and suggested revisions that have been incorporated.

Because of the large number of people from Alaska to California who also contributed to this study, it would be impractical to individu­ ally thank everyone involved. Personnel of the U. S. Fish and Wildlife

Service, California Department of Fish and Game, British Columbia Fish and Wildlife Branch, and Canadian Wildlife Service as well as private individuals including naturalists, sportsmen, landowners, and university students helped conduct observations and provided other assistance. I wish to thank all of these people as a group.

A special debt of gratitude is owed to biologist W. E. "Bud"

Rienecker and wardens Jack Rhea and the late Leon H. Nelson of the

California Department of Fish and Game and law enforcement agents Wallace

B. Smith and Alva E. Weinrich of the U. S. Fish and Wildlife Service for vi field assistance. Employed and volunteer workers who conducted observa­ tions while I was in other areas include William E. Rodstrom, Gary

Lester, Tom Greener, Ernest P. Camillari, William G. Henry, Jack T.

Loris, Randy March, and Larry R. Kludt.

During the study, housing was provided by the Gray Lodge, Los

Banos, and Grizzly Island Wildlife Areas and the Izembek, San Luis, and

Willapa National Wildlife Refuges. I wouLd like to thank the respective state and federal property managers John R. Cowan, Jerome C. Cawthorn,

Clyde S. Edon, John E. Sarvis, Leon A. Littlefield, and Joseph W. Welch for this privilege and their hospitality.

The late Roger Wilbur, owner of the West Butte Farms and Butte

Creek Farms; Paul L. Davies, owner of the Faith Ranch; C. E. Nemethi, owner of the Nemethi Land and Cattle Company; Henry and Robert Westbrook, owners of the Reservation Ranch; and Loren C. Bliss, owner of the L. C.

Bliss and Sons Livestock Company, kindly allowed access to their proper­ ties.

Janice R. Chandler, secretary at the Wildlife Research Field

Station, typed the thesis drafts.

Finally, I would like to thank G. Vernon Byrd for first intro­ ducing me to the world of the Aleutian Canada goose. TABLE OF CONTENTS

Page

ABSTRACT iii

ACKNOWLEDGEMENTS

LIST OF TABLES xi

LIST OF FIGURES xiv

INTRODUCTION 1

Overview 1

Historical Perspective 2

STUDY AREA 9

Description 9

General Study Area 9

Localized Study Areas in California 11

Crescent City 11

Butte Sink 15

Grizzly Island 17

Faith Ranch and Los Banos 19

Weather 21

METHODS 23

RESULTS 27

Distribution 27

Fall Migration 27

Aleutian Islands-Alaska Peninsula 27

Northwest Coast 29

Northern California 29 viii

TABLE OF CONTENTS (continued) Page

Wintering Grounds 33

Sacramento Valley 33

Sacramento-San Joaquin River Delta and Grizzly Island . 37

San Joaquin Valley 39

Other use areas 43

Spring Migration 46

Departure from the Central Valley 46

Occurrence in Humboldt County 47

Crescent City stating grounds 47

North of California 54

Ecology on Main Use Areas 56

Butte Sink 56

Localized use patterns 56

Food items 58

Relation to other wildlife 58

Relation to human activity 59

Grizzly Island 61

Localized use patterns 61

Food items 61

Relation to other wildlife 63

Relation to human activity 63

Faith Ranch 64

Localized use patterns 64

Food items 64

Relation to other wildlife 67

Relation to human activity 67 ix

TABLE OF CONTENTS (continued) Page

Los Banos 68

Localized use patterns 68

Food items 68

Relation to other wildlife 72

Relation to human activity 72

Crescent City 73

Localized use patterns 73

Food items 77

Relation to other wildlife 77

Relation to human activity 78

Population 79

Documented Mortality 79

Hunting loss 82

Disease 82

Trapping mortality 85

Unknown causes 85

Known Survival 86

Population Levels 88

Fall 1975 88

Spring 1976 89

Fall 1976 91

Spring 1977 91

DISCUSSION 94

Distribution 94

Fall Migration 94

Wintering Areas 97

TABLE OF CONTENTS (continued) Page

Spring Migration 102

Ecology on Main Use Areas 106

Localized Use Patterns 106

Food Items 107

Relation to Other Wildlife 107

Relation to Human Activity 108

Population 109

Mortality Factors 109

Mortality Rates and Survival 111

Population Levels 117

Pre-Hunting Closure Population Level 118

Population Increases 118

CONCLUSION AND RECOMMENDATIONS 120

REFERENCES CITED 124

APPENDICES

A. Common and Scientific Names of Avian Species from American Ornithologists' Union (1957) and Bellrose (1978) 131

B. Common and Scientific Names of Plant Species from Munz (1959), Mason (1957), and Usher (1974) 132

LIST OF TABLES

Table Page

1 Vegetation Types and Dominant Plants at Point Saint George, Reservation Ranch, and McNamara Field 14

2 Monthly Precipitation at Sacramento Weather Station, Winters 1975-76 and 1976-77 22

3 Observations of Migrating Aleutian Canada Geese in the Aleutian Islands, Falls 1976 through 1978 28

4 Unsuccessful Surveys for Aleutian Canada Geese, Falls 1975 and 1976 30

5 Numbers and Time of Occurrence of Aleutian Canada Geese Present at Crescent City, Falls 1975 and 1976 32

6 Occurrence and Flock Size of Aleutian Canada Geese in the Butte Sink, Fall 1976 34

7 Records of Aleutian Canada Geese in the Sacramento Valley, Winters 1975-76 and 1976-77 36

8 Aleutian Canada Geese Observed at Grizzly Island Wildlife Area, Winters 1975-76 and 1976-77 38

9 Daily Counts of Aleutian Canada Geese on the Faith Ranch, 25 December 1976 to 7 March 1977 40

10 Daily Counts of Aleutian Canada Geese on the Nemethi Ranch and Adjacent Areas, 17 January to 13 March 1977 42

11 Records of Aleutian Canada Geese in the San Joaquin Valley, Winters 1975-76 and 1976-77 44

12 Records of Verified and Probable Aleutian Canada Geese along Coastal Humboldt County, February and March 1977 and 1978 48

13 Daily Counts of Aleutian Canada Geese Observed at Crescent City, Spring 1976 49 xii

LIST OF TABLES (continued)

Table Page

14 Daily Counts of Aleutian Canada Geese Observed at Crescent City, Spring 1977 50

15 Number of Marked Individuals Identified during Observations of Aleutian Canada Geese at Crescent City, Springs 1976 and 1977 53

16 Observations of Migrating Aleutian Canada Geese in the Aleutian Islands, Springs 1975 through 1978 . . 55

17 Composition of Ground Cover in Planted Pastures Used by Aleutian Canada Geese on the Faith Ranch, Winter 1976-77 66

18 Composition of Ground Cover in Planted Pastures Used by Aleutian Canada Geese on the Nemethi Ranch, Winter 1976-77 70

19 Composition of Ground Cover in Fields Used by Aleutian Canada Geese South of the Los Banos Sewage Treatment Ponds, Winter 1976-77 71

20 Average Starting Times of Daily Flights from Castle Rock to the Mainland Pastures at Crescent City, Spring 1976 75

21 Average Starting Times of Daily Flights from Castle Rock to the Mainland Pastures at Crescent City, Spring 1977 76

22 Documented Aleutian Canada Goose Mortality, Winter 1975-76 80

23 Documented Aleutian Canada Goose Mortality, Winter 1976-77 81

24 Geographic and Temporal Composition of Documented Hunting Mortality of Aleutian Canada Geese, Winters 1975-76 and 1976-77 83

25 Juvenile Versus Adult Vulnerability to Hunting of Aleutian Canada Geese Calculated by Band Recoveries during Winters 1975-76 and 1976-77 84

26 Status of Marked Aleutian Canada Geese from October 1975 to April 1977 Based on Band Observations and Recoveries 87 LIST OF TABLES (continued)

Table Page

27 Observed Occurrence of Previously Marked Aleutian Canada Geese at Crescent City, Spring 1976 before and after Peak Count on 30 March 90

28 Observed Occurrence of Previously Marked Aleutian Canada Geese at Crescent City, Spring 1977 before and after Peak Count on 25 March 92

29 Comparison of Maximum Winter Mortality Rates of Aleutian Canada Geese with Annual Mortality rates of Other Races of Small Canada Geese 114

30 Comparison of Estimated Winter 1976-77 Mortality Based on Population Counts and Sightings of Banded Birds 116

LIST OF FIGURES

Figure Page

1 Aleutian Islands and Pacific Coast of North America 10

2 Castle Rock and Crescent City Area 12

3 Southern Portion of the Butte Sink 16

4 Grizzly Island and Suisun Marsh 18

5 Modesto and Los Banos Area 20

6 Aleutian Canada Goose Use Areas in the Butte Sink, Winters 1975-76 and 1976-77 57

7 Sacramento Valley Canada Goose Hunting Closure

and Subsequent Modifications 60

8 Aleutian Canada Goose Use Areas in the Grizzly Island Area, Winters 1975-76 and 1976-77 62

9 Aleutian Canada Goose Use Areas on the Faith Ranch and Vicinity, Winter 1976-77 65

10 Aleutian Canada Goose Use Areas on the Nemethi Ranch and Vicinity, Winter 1976-77 69

11 Aleutian Canada Goose Use Areas at Crescent City, Springs 1976 and 1977 74

12 Wintering Range of Aleutian Canada Geese 103 INTRODUCTION

Overview

The diminutive Aleutian Canada goose (Branta canadensis leucopareia) is thought to have been formerly common in the Pacific Fly­ way. The known breeding range of this subspecies extended from the

Islands of the Four Mountains in the eastern Aleutian Islands (Jochelson

1933) westward to the Commander (Stejneger 1883) and Kurile Islands

(Snow 1897) of the Soviet Union. These geese were reported to have bred by the thousands in the Near Island group of the western Aleutian

Islands (Turner 1886, Clark 1910) where they were described as the most abundant breeder on Agattu Island. The wintering range was reported to be in Japan and from British Columbia to northwestern Mexico (Delacour

1954, Hansen and Nelson 1964). However, introduction of Arctic foxes

(Alopex lagopus) in the Aleutian Islands resulted in the elimination of nesting geese on every island on which the foxes were released, and the near extinction of this race. Today, Buldir, one of the few islands not receiving such an introduction, is the sole remaining area that supports a known breeding population of Aleutian Canada geese (Jones

1963, Byrd and Springer 1976).

In 1967, under the provisions of the Endangered Species Act, the

Aleutian Canada goose was listed as endangered. By 1974, work on the subspecies was accelerated to involve study and management on the breeding, migration and wintering grounds. A formal Recovery Team, consisting of biologists from the U. S. Fish and Wildlife Service and the California and Alaska Departments of Fish and Game, was appointed 2

in 1975 to advise and assist on the restoration of Aleutian Canada

geese. A draft recovery plan was formulated (Byrd and Springer 1976,

Springer et al. 1978) and subsequently approved in 1979. This plan con­

sists of two major parts:

1)Maintain the wild population of Aleutian Canada geese at the

1977 level of 1150 or greater.

2)Reestablish self-sustaining populations of geese (50 breeding

pairs) on three former breeding areas.

One aspect of this recovery plan is to determine the current

migration and wintering distribution and habits of the remnant population

of Aleutian geese. These data will be used to maintain or modify pro­

tective measures that have been initiated to aid in the restoration of

this subspecies. The objectives of this study were to determine:

1)Migration, wintering areas, and time of occurrence of

Aleutian Canada geese in North America.

2)Population status of the birds.

3)Habits and general wintering ecology of the birds.

4)Threats to the birds away from the breeding grounds and

possible management solutions.

This thesis summarizes the findings of the study with emphasis on migration, wintering areas, and population status of Aleutian Canada geese.

Historical Perspective

The taxonomy of small and intermediate-sized Canada geese wintering in specific areas of western North America has remained in a state of confusion until relatively recent times (Swarth 1913, Delacour 1951). Even today, no consensus on the subspecific identity of various races has been reached by all authorities (Palmer 1976). This historic

situation was especially acute for Aleutian Canada geese. A historical

list of the names that have been ascribed to birds now considered to be

or matching the appearance of this subspecies include:

Anser leucopareius, Brandt (1836)

Branta minima (part), Cackling goose, Ridgway (1885)

Branta canadensis minima (part), [Cackling goose], Peters (1931)

Branta canadensis hutchinsii (part), [Hutchins' goose], Peters

(1931)

Branta canadensis leucopareia (part), Lesser Canada goose, AOU

(1931)

Branta hutchinsii asiatica (part), Asiatic Cackling goose,

Aldrich (1946)

Branta canadensis leucopareia, Aleutian Canada goose, Delacour

(1951, 1954)

Until limited by Delacour (1951) to birds that bred in the

Aleutian Islands, Aleutian Canada geese were variously lumped with other intermediate-sized Canadas as Hutchins' geese, sometimes as cackling geese, and later as lesser Canada geese. Some authorities (Brooks 1914,

Taverner 1929) called for classifying these geese, as well as the smaller cackling Canada geese, as a separate species from the larger forms of

Canada geese. Figgins (1920) proposed that Hutchins' geese be eliminated as a subspecies, that cackling geese and any large forms of Canada geese be classified as two distinct species, and that any intermediate birds be considered hybrids between the two.

Along with these changes in nomenclature, ornithologists often assigned wintering Canada geese to subspecies without the benefit of adequate specimen series from the breeding grounds. This often resulted 4 in misidentification of specimens and subspecies occurrence that plagues the literature even today. Workers on the breeding grounds, without thorough knowledge of the limits of the morphological characters of birds within the same breeding population and basing their identifi­ cation on early literature that had been developed primarily from the wintering areas, also added to the confusion. A breeding bird collected on Attu in 1911 was recorded as a cackling Canada goose by Bent (1925) and identified as such by Aldrich (1946), whereas on 48-km-distant

Agattu, Turner (1886) recorded the breeding birds as both Hutchins' and cackling geese and Aldrich identified a specimen collected in 1937 as the former race (Murie 1959). As a result, it was accepted, although with reservations (Bent 1925, Murie 1959), that two separate subspecies occupied the same breeding range in the Aleutian Islands. Geese nesting in the Commander and Kuriles were described by Aldrich (1946) as yet another subspecies, Asiatic cackling goose on the basis of five specimens.

However, these specimens fell within the variability of Aleutian Canada geese as described by Hellmayr and Conover (1948) and were later con­ sidered by Kuroda in 1952 (Bellrose 1978) to be Aleutians.

From this period, a sketchy picture of the early occurrence of

Aleutian Canada geese has emerged. The historic migration route of

Aleutian Canada geese was described by Jochelson (1933) and Murie (1959) as eastward along the Aleutian Island chain to the western end of the

Alaska Peninsula where they gathered in masses from early September to

November before departing southward. Jochelson added that during fall migration, birds stopped to rest on the islands. They returned in April and flew westward along the island chain to their breeding grounds.

However, little was clearly known about the specific wintering areas of

Aleutian Canada geese. Bent (1925) and Grinnell et al. (1918) reported 5 that the wintering range for both the cackling and "Hutchins" geese extended from southern British Columbia to southern California. These geese occurred most abundantly in the Central Valley of California

(Grinnell 1915). Heerman (1859) stated that birds that he called

Hutchins' geese arrived in California during late September to early

October. He observed large numbers in the Suisun Valley throughout the winter, and provided the following description:

On examination, I found a great difference in the size of this bird, but beyond this could discover no peculiar characteristics by which to mark them as a distinct species. Many have from a few white feathers up to a full white ring on the neck, at the point where the black joins the gray of the breast. Intermediate grades so closely approaching one another in size, form, and color render it impossible to make any decided certain, and marked classification among them.

In addition to the geese wintering on the west coast of North

America, some Aleutian Canada geese migrated eastward to Asia. These geese were possibly those nesting in the Commander and Kurile Islands, and the extreme western Aleutian Islands. Early records indicate that

Aleutian Canada geese were fairly common wintering birds in Japan until the sudden disappearance of the large flocks during the latter half of the 19th century (Austin 1949). Although greatly reduced in numbers, these geese were recorded as regular winter visitors until 1922

(Kuroda 1939). After that time, documented occurrence was reduced to sporadic sightings of one to five individuals (Austin 1949). Yocom

(1970) reported that, although rare, Canada geese have been encountered in the Kashmir Valley of northern India. However, the subspecific identity of these Canada geese had not been established.

From about 1836 (Tikhmenev 1861) to about 1930 (Jones 1963), arctic foxes were introduced into the Aleutian Islands for the purpose of fur farming. Originally conducted on a small scale, this practice 6

was accelerated in the 1920's until all but 11 islands and a few smaller

islets had been stocked with foxes (Sekora 1973). Because of the dry- land nesting and molting habits of the geese, they are extremely vulner­

able to predation by foxes, and eventually the nesting Aleutian Canada

geese were eliminated from the islands on which the foxes had been

introduced (Byrd and Springer 1976). Although this predation was

apparently the primary cause for the population decline, other factors

may also have played a part. Excessive market hunting in central

California as described by Grinnell et al. (1918) of small Canada geese

matching the description of Aleutians took a heavy toll of birds.

Hunting on the breeding grounds as described by Turner (1886) put

further pressure on these reduced populations.

In surveys of the Aleutian Islands from 1936 to 1938, Murie

(1959) found that Aleutian Canada geese had been eliminated from almost

all islands the foxes had been released upon. Of the few remaining fox-

free islands, his expedition found one goose on Chagulak Island in the

eastern Aleutians, and goose sign on Buldir Island in the western

Aleutians. In the fur-farm-leased Near Island group, where nesting

geese had formerly been abundant, a few pairs were observed on Agattu,

while only feathers and droppings were found on Alaid. He found that

the geese were so scarce that some of the younger Aleut natives were

unaware of any Canada goose migration along the Aleutian Island chain.

Concurrently with this, several authors (Grinnell et al. 1918,

Bent 1925) noted a general decline in the number of small and inter­

mediate sized Canada geese wintering throughout California. Although

several subspecies of Canada geese were probably also involved in the 7 lowered population levels, the loss of Aleutian Canada geese undoubtedly comprised a part of this overall decline.

In the years following the 1930's the status of the Aleutian

Canada geese was unknown. There were no records from the Aleutian

Islands, and any remaining geese went unnoticed among the flocks of other Canada geese in the wintering areas. Some (Delacour 1951) believed they were probably extinct. However, sporadic sightings of the geese in the western Aleutian Islands were recorded in the late 1940's to early

1960's (Krog 1953, Coats 1955, Kenyon 1961, Jones 1963). Searches for

Aleutian Canada geese culminated in the 1962 rediscovery of a small population nesting on Buldir Island (Jones 1963).

With documentation of the existence of a breeding population, the attempts to eliminate foxes from former goose nesting islands, which had begun in the late 1940's, was intensified. Aerial and ground poisoning along with trapping and shooting resulted in the elimination of foxes from Amchitka by 1965 and was thought to have removed the foxes from Agattu, Nizki, and Alaid Islands by 1970 (Springer et al.

1978). In addition, goslings were captured on Buldir in 1963, and used to initiate a captive propagation effort at the Patuxent Wildlife

Research Center, Laurel, Maryland. Progeny from the captive stock were used in an unsuccessful reintroduction attempt on Amchitka in 1971

(Byrd and Springer 1976, Springer et al. 1978). However, the migration patterns and wintering areas of the Buldir population was still unknown.

In the summer of 1974, staff from the Aleutian Islands National

Wildlife Refuge went ashore at Buldir to study and band the wild geese and at Agattu to release captive-reared Aleutians into the wild. 8

Although remaining foxes were discovered on Agattu, the geese were

released and monitored through the summer.

Band recoveries during the 1974-75 waterfowl hunting season

revealed that Aleutian geese were present in the Central Valley and

northern coastal counties of California. The known records of Aleutians

included nine wild banded birds shot in Glenn, Sutter, Stanislaus, and

Merced Counties; a banded captive-reared bird shot in Del Norte County,

and another found dead in Mendocino County; and four unbanded wild birds

shot in Humboldt County (Byrd and Springer 1976). In March 1975 a flock

of Aleutian geese, including marked birds, was discovered near Crescent

City, Del Norte County (Springer 1975). These birds, all judged to be

Aleutians, numbered 790 in mid-April. On 23 April the geese began

departing northward and by the end of the month all had left the area.

On 3 May 1975, a flock of 70 Aleutians, including several color-marked

birds, were reported on Sand Island, Clatsop County, Oregon, near the

mouth of the Columbia River (J. M. Welch pers. comm.).

In an effort to protect wintering Aleutian geese, the California

Department of Fish and Game in conjunction with the U. S. Fish and Wild­ life Service closed three areas in California to the hunting of all

Canada geese during the 1975-76 waterfowl hunting season. These closures were based on the location and time of occurrence of the 1974-75 recoveries, (Byrd and Springer 1976). The northwest coastal counties of

Del Norte, Humboldt, and Mendocino were closed for the entire waterfowl season; part of Glenn and Colusa Counties in the Sacramento Valley was closed from the 18 October opening date to 15 December; and part of San

Joaquin, Stanislaus, and Merced Counties in the San Joaquin Valley was closed from 15 December to the 18 January end of the waterfowl hunting season. STUDY AREA

Description

General Study Area

The general study area encompassed the western part of the

Pacific Flyway, from Buldir Island, Alaska, to northern Mexico (Fig. 1).

The Aleutian Islands, Alaska, is a major geographical region

within the study area. Consisting of over 70 named major islands, this

chain of mountain tops stretches from the base of the Alaska Peninsula

westward 2240 km toward the Kamchatka Peninsula of the Soviet Union.

All but seven of the major named islands are under federal jurisdiction

as the Aleutian Islands National Wildlife Refuge. This treeless, wind­

swept region is characterized by rain, fog, and violent storms and is

host to vast numbers of birds and marine mammals. A more detailed de­

scription of the geography, history, fauna, and current status of the

Aleutian Islands is provided by Murie (1959) and Sekora (1973).

The northwestern coast of North America stretching from coastal

British Columbia to Del Norte and Humboldt Counties, California consti­

tutes the second major geographic region within the study area. The

Willamette Valley of Oregon is also included in this region for the

purposes of this study. This region is characterized by a cool climate,

dense conifer forests, and rugged coastlines. Much of the agricultural

development in the area consists of pastureland. Rudd (1968), Stalitore et al.(1973) and Fremlin (1974), provide detailed descriptions of the physical features and climate of this region. 1 Figure 1. Aleutian Islands and Pacific Coast of North America. 0 11

The Great or Central Valley of California, which lies as a 720­ x 96-km trench through the center of the state, constitutes the other geographic region within the study area. This valley lies between the

Coast Range and the Sierra Nevada and extends from the Cascade Mountains in the north to the Tehachapi Mountains in the South (Stalitore et al.

1973). The Central Valley is further subdivided into the Sacramento

Valley, the San Joaquin Valley, and the Sacramento-San Joaquin River

Delta. The Sacramento Valley occupies the northern part of the Central

Valley and encompasses all of Sacramento, Sutter, and Yolo Counties and most of Butte, Colusa, Glenn, Solano, and Tehama Counties. The adjacent

San Joaquin Valley contains all of San Joaquin, Stanislaus, Merced,

Fresno, and Kings Counties and parts of Kern, Tulare, Madera Counties and Contra Costa Counties. The Sacramento-San Joaquin Delta lies near the center of the Central Valley at the confluence of the Sacramento and

San Joaquin Rivers and includes part of Solano, Contra Costa, and

Sacramento Counties (California Department of Water Resources 1974).

Detailed descriptions of these areas are provided by Stalitore et al.

(1973), California Department of Water Resources (1974), and Durrenberger

(1976).

Localized Study Areas in California

Crescent City. The northernmost localized study area in Cali­ fornia is situated 1.6 to 3.2 km north of Crescent City, Del Norte

County. Major components of this study area include Castle Rock (Castle

Island of Osborne, 1972), Point Saint George, pastures of the Reservation

Ranch and the former L. C. Bliss and Sons Livestock Company (purchased in 1979 by the State of California), and McNamara Field, the Del Norte County airport (Fig. 2). 12

Figure 2. Castle Rock and Crescent City Area. 13 The 5.2-ha Castle Rock lies 1 km offshore from Point Saint

George and is 72 m in height. The east side slopes to a sand and cobble beach while most of the remaining island perimeter consists of steep seaslopes and nearly vertical cliffs ranging from 15 to 60 m high. The main feature of the top of the island is an eastward sloping 61- x 91-m vegetated flat flanked on the west by two basalt peaks. Osborne (1972) provides a more detailed description of Castle Rock.

The adjacent mainland study area lies on the Smith River Plain.

The general topography is gently rolling with low relief sand dunes, gullies, and drainages. The original vegetative cover was dominated by bunchgrasses, sedges, and scattered willow thickets. Many of the native plant species have now been replaced by cultivated pasture grasses (U. S.

Fish and Wildlife Service 1978).

Table 1 lists the major vegetation types, approximate percent occurrence, and dominant plant species for the area encompassed by Point

Saint George, Reservation Ranch, and McNamara Field. The Bliss ranch pastures consist almost entirely of closely cropped, introduced grasses and clovers.

The climate in the Crescent City area is Mediterranean in character. Average summer and winter temperatures show little variation.

Mean minimum temperature in January is 2.2°C and mean maximum in July is

21.1°C. The area receives 2286 mm of precipitation annually, with over

90 percent occurring from October to April (U. S. Fish and Wildlife

Service 1978). Fog is a common occurrence, especially during morning and evening hours in the spring. The prevailing winds are from the north and northwest. 14

Table 1. Vegetation Types and Dominant Plants at Point Saint George, Reservation Ranch, and McNamara Field.

Upland Sandy Fields (ungrazed) 40%

Salt rush Bush lupine Wild buckwheat Knotweed

Upland Pasture (grazed) 30%

Velvet grass Red top Iris Cat's ear

Lowland Swales 10%

Slough sedge Reed grass Cinquefoil Common rush

Coastal Headlands 10%

Lupine Beach strawberry Rush Gum plant

Spruce Forest 5%

Sitka spruce Salmon berry California bay Red alder

Willow Thickets 5%

Willows Spiraea Twin berry Salmon berry a From Gary Lester, Redwood National Park 15

Butte Sink. The Butte Sink is located in the eastern side of the Sacramento Valley and encompasses parts of northeastern Colusa

County, northwestern Sutter County, and southwestern Butte County. This

6808-ha area is bordered on the west and south by the Sacramento River

and on the east by the Sutter Buttes. Major areas of interest within

the Sink for the purpose of this study are the 406-ha West Butte Farms,

the 1022-ha Butte Creek Farms, and the 202 ha of cropland of the 833

Reclamation District (Fig. 3).

The Butte Sink lies in the alluvial flood plain of the Sacramento

River and is covered by medium textured alluvial and fine textured clay

soils. The Sink is flat with shallow drainages running north and south.

Most of the Sink is less than 16.8 m above sea level, and the southern

end is about 13.6 m in elevation, thus making the area lower than the

Sacramento River (U. S. Fish and Wildlife Service 1979). When the

Sacramento River and Butte Creek overflow their banks, the water spills into the Butte Sink and is impounded through the winter and spring.

The native habitats consist of meandering oxbows and marshy low­

lands with three generalized plant communities. Along Butte Creek and

the drier sites are riparian plant associations such as willows, Fremont

cottonwood, valley oak, and shade-tolerant understory plants. Inter­

mittently flooded areas with smartweeds, bulrushes, sedges, and annual

grasses; and permanently flooded marsh areas with aquatic plant species

such as duckweeds, spikerushes, cattails, and others form the other two

communities (Arend 1967).

Approximately 2800 ha of this native habitat has been supplanted

through drainage and subsequent agricultural development. The major

crops grown are rice, melons, beans, tomatoes, sorghum, and safflower. 16

Figure 3. Southern Portion of the Butte Sink. 17

Most of the Butte Sink, both native habitat and agricultural lands, is owned or leased by hunting clubs and flooded during the winter.

The climate in the Butte Sink is characterized by hot, dry summers from May through October and cool, wet winters from November through April. At 3.2-km-distant Colusa, Colusa County, the mean maximum temperatures in July is 35°C and mean minimum temperatures in January is

1.5°C. Annual precipitation averages 508 mm (U. S. Department of

Commerce 1975). During winter, extensive ground fog occurs commonly.

A more detailed description of the vegetation and wildlife of the Butte Sink is provided by Arend (1967).

Grizzly Island. Grizzly Island is located in southeastern

Solano County and is part of the 21,800-ha Suisun Marsh within the

Sacramento-San Joaquin River Delta. It is encircled by Suisun, Grizzly, and Honker Bays and Montezuma Slough (Fig: 4). Approximately one-fourth of the island is occupied by the 3340-ha Grizzly Island unit of the

Grizzly Island Wildlife Area, a management area owned by the California

Department of Fish and Game, and the rest is under private ownership as agricultural lands and duck hunting clubs.

The area was formed from alluvial deposits of mud, muck, and loam from the Sacramento and San Joaquin Rivers and peat formation within the island basin. The overall topography is flat with elevations ranging from 2.5 m above to 1 m below sea level. The resultant landscape is that of brackish marshland subjected to intermittent saltwater intrusion. The major floristic components of the area consist of both salt and fresh­ water plant associations. Historically, the major habitat types con­ sisted of tidal marshes and overflow lands, and grasslands on the drier sites. Much of this has been changed by draining and water level 18 Benicia Figure 4. Grizzly Island and Suisun Marsh. Figure 4. Grizzly Island and 19 manipulation dating back as early as the late 1800's (Mall 1969).

Management of Grizzly Island Wildlife Area maintains a vegetative com­ munity ratio of 62 percent marshland, 30 percent cropland, 6 percent grasslands, and 1 percent shrubs and trees. Most of the private prop­ erty is either pastureland or natural marshes.

The climate is Mediterranean in character and similar in temper­ ature to that of the Sacramento and San Joaquin Valleys. Annual rainfall averages 457 mm and occurs mostly between November and March (Mall 1969).

Faith Ranch and. Los Banos. The Faith Ranch, Stanislaus County, and the Los Banos area, Merced County, are lcoated 70 km apart in the upper San Joaquin Valley (Fig. 5). Because of their prominity to each other and the uniformity of the general area both locations are dis­ cussed together in this section.

The 930-ha Faith Ranch lies at the confluence of the Stanislaus and San Joaquin Rivers, 18 km west of Modesto. The ranch is managed for cattle raising, with most of the property in flood-irrigated pasture- lands of cultivated grasses. However, small ponds and sloughs with native emergent vegetation are scattered throughout the property. This study also included the adjacent 6400-ha Mapes Ranch and 680-ha Vierra

Ranch and the 6.4-km distant, 640-ha Bogetti Ranch.

The other segment of this intensively studied area extended from

1.6 km northeast to 6.4 km south of Los Banos. The northern portion consists of the 203-ha Nemethi Land and Cattle Company and the adjacent

278 ha of sewage treatment ponds and pastureland under the municipal ownership of Los Banos. The Nemethi ranch is managed as a flood- irrigated pasture, divided into 8-ha fenced units for cattle grazing.

During the study the city-owned pastureland was leased for cattle grazing. 20

Figure 5. Modesto and Los Banos Area. 21

The 259-ha Britto Gun Club lies in the southern portion of this study

area. The property is managed as a flooded waterfowl hunting club dur­

ing the winter months and as grazing land during the rest of the year.

The intervening area between the Nemethi ranch and the Britto Gun Club

consists primarily of agricultural land and private duck hunting clubs.

Like most of the Central Valley, the area encompassing the

Faith Ranch and Los Banos is recent in geologic age and was formed

primarily by basin deposits of alluvium from river overflows. Histori­

cally, this region was an extensive native grasslands. With a climate

essentially the same as that of the Sacramento Valley, the annual cycle was dry parched grasslands during the summer, and broad shallow marsh­ lands formed from rain and overflow waters during the winter.

Today much of the area has been transformed by levees and

intensive agriculture. Major crops in the region include cotton,

orchard crops, sugar beets, tomatoes, corn, and rangeland under varying

degrees of management. However, much of the native grassland and marsh habitat of the area has been preserved by the presence of private hunt­ ing clubs, three national wildlife refuges, and two state wildlife areas.

Weather

The main study areas within California were subjected to a statewide drought during both winters of the study. The years 1976 and

1977 were the driest since 1934. During the periods of September to

April 1975-76 and September to April 1976-77 the precipitation deficit recorded at the centrally located state capital in Sacramento,

Sacramento County, was 268 mm and 288 mm, respectively (Table 2). 22

Table 2. Monthly Precipitation at Sacramento Weather Station, Winters 1975-76 and 1976-77. a

1975-76 1976-77

Precipitation Deviation Precipitation Deviation Month (in mm) from Normal (in mm) from Normal

September 0 - 6 21 15

October 59 32 0 -26

November 10 -47 16 -41

December 8 -75 15 -67

January 9 -91 35 -66

February 38 -35 28 -45

March 15 -43 34 -25

April 39 - 3 9 -33

Total 178 -268 158 -288 aData from U. S. Department of Commerce (1975, 1976, 1977). METHODS

Full-time field investigations were conducted from October 1975 to May 1976 and October 1976 to May 1977, with part-time field observa­ tions from October 1977 to May 1978. In addition, migration and band observation data were collected from May to October 1975 through 1978 by myself and other field personnel while employed by the Aleutian Islands

National Wildlife Refuge.

A total of 536 Aleutian geese were banded with U. S. Fish and

Wildlife Service (USFWS) monel leg bands both prior to and during the study. Of this total, 323 were captured by hand at Buldir Island during

July and August 1974 through 1976, and 213 were captured in cannon- trapping operations in Crescent City during March and April 1976 and

1977. To provide positive identification in the field, 430 of these birds were fitted with plastic leg markers (34 mm high and 14 mm inside diameter) and 98 were fitted with plastic neck collars (20 mm high and

40 mm inside diameter). The markers were color coded by age class and year banded, and inscribed with numeric and alphanumeric codes. Sex of the birds was determined by cloacal examination (Hochbaum 1942) and age by a combination of bursal examination (Hochbaum 1942), plumage characteristics (Hanson 1962), and retrices notching (Taber 1971).

Searches for Aleutian Canada geese were conducted by direct observation. Flocks of small and intermediate-sized Canada geese throughout the study area were viewed for the presence of Aleutian geese.

Observations were made with 7X binoculars, 20-40X spotting scopes, and

80-130X Questar telescopes. Subspecies identity was based on the 24 presence of a neck ring, plumage coloration, size, general configuration, and stance. However, because of similarities of Aleutians with the slightly smaller cackling Canada goose, and the slightly larger Taverner's

Canada goose absolute identity was based on the presence of known banded and marked Aleutians. Unmarked birds bearing Aleutian characteristics were considered to be that race when in flocks containing marked Aleutian

Canada geese. Birds in flocks of six or more were considered to be

Aleutians if all birds in the group displayed Aleutian characteristics, even if no markers were present or observed. Single or loosely scattered individuals resembling this race which were in flocks of other sub­ species of Canada geese were not considered to be Aleutians. Any obser­ vations of Canada geese west of Unimak were considered to be of Aleutian

Canada geese.

Observations were conducted during the fall of 1975 and 1976 to determine the timing and route of migration as Aleutian Canada geese moved from the breeding grounds to the wintering areas in. California.

The presence of geese at Buldir was monitored during September 1976 to determine fall departure dates. From 18 September to 10 October 1976, areas of Izembek National Wildlife Refuge and Unimak Island were searched for migrating Aleutian Canada geese. During 8 October-10

November 1975 and 11 October-1 November 1976, searches were conducted from British Columbia southward to northern California. Principal areas visited included the Queen Charlotte Islands, Tofino area, Nanaimo area, and Vancouver area of British Columbia; Willapa Bay National Wildlife

Refuge in Washington; and William L. Finley National Wildlife Refuge complex in the Willamette Valley, Oregon. Offshore islands between 25

Oregon and Crescent City, California, were viewed from the mainland for the presence of geese.

Use areas in California were investigated on the basis of loca­ tions given in band recoveries from the 1974-76 to 1976-77 waterfowl hunting seasons, locations of known Canada goose concentration, as well as areas of documented Aleutian Canada goose presence. Hunters reporting band recoveries to the Bird Banding Laboratory, Laurel, Maryland, or to local wildlife agency personnel were contacted to determine exact loca­ tion, date, flock size, and circumstances surrounding the recovery.

Interviews with landowners, hunters, and wildlife agency personnel provided additional information on local concentrations of geese.

After the majority of the geese left California in the spring,

Willapa National Wildlife Refuge and surrounding areas were searched on

24-27 April, 1976 and 22-24 April 1977 in an attempt to locate northward migrating birds.

Searches of likely areas were conducted primarily from the ground. In some instances, single-engine aircraft were used to locate goose flocks which were later observed for subspecies identity from the ground.

As use areas were identified, they were monitored to determine:

1. Timing of use

2. Number of Aleutian geese present

3. Identity of individually marked birds

4. Use patterns of the area

5. Interactions with other species and subspecies

6. Threats to the geese 26

Throughout the study, effort was expended to contact personnel from state, provincial and federal wildlife agencies, landowners, water­ fowl hunters, representatives from conservation organizations, and local naturalists to inform them of the project and solicit their aid in conducting and reporting observations. The establishment of this net­ work of informed observers was one of the major objectives in spring and fall activities in British Columbia, Washington, and Oregon. Newspaper articles encouraged local residents to report any sightings of marked geese. 2 Randomly selected 1-m plots along line transects were used to determine species identity and importance (expressed as percent ground cover) of potential forage items in fields utilized by Aleutian geese at the Faith Ranch and near Los Banos. Species composition within each plot was estimated to the nearest 5 percent and used to determine average plant species composition in the fields.

For the purposes of this study, winter is defined as the time from southward migration in September to northward migration in May.

Fall (September-November) and spring (March-May) are considered subunits of this time period.

Unless indicated otherwise, goose age class designations are adult (any bird more than one year of age) and gosling or juvenile (any bird less than one year old).

Common and scientific names of birds (Appendix A) are based on the classification of Bellrose (1978) for the family Anatidae and the

American Ornithologists' Union (1957) for all other species. Common and scientific names of plants (Appendix B) are based on Mason (1957) and

Munz (1959). Names of cultivated plants not listed in Munz or Mason follow the terminology of Usher (1974). RESULTS

Distribution

Fall Migration

Aleutian Islands-Alaska Peninsula. Work conducted at Buldir

Island in summers 1975 and 1976 showed that geese departed the nesting grounds from late August through the end of September (G. V. Byrd and

D. W. Woolington unpubl. MS.). Less than 200 birds were still present when investigators departed Buldir on 29 September 1976. Due to logis­ tical difficulties, systematic surveys for geese migrating along the length of the Aleutian Island chain were not possible; therefore, observations were reduced to sightings of opportunity made by widely scattered observers (Table 3). Aleutian Canada geese were observed at points along the island chain from the western Aleutians to the eastern­ most island of Unimak. Most sightings occurred east of Buldir Island, although, in 1978, sightings of wild-reared Aleutian geese were recorded on Agattu Island, 144 km west of Buldir. Of the recorded fall observa­ tions, (60 percent) occurred in August and September.

No Aleutian Canada geese were observed during 3 weeks of searches from 18 September to 9 October 1976 at Izembek National Wild­ life Range. However, it was during this time that two flocks of two and seven Canadas, all bearing characteristics of Aleutians, were observed by J. Nelson near Cape Sarichef, Unimak Island, 160 km west of Izembek

National Wildlife Range. No positive sightings of Aleutian geese were made in subsequent surveys conducted from 1976 through 1978 at Izembek 28

Table 3. Observations of Migrating Aleutian Canada Geese in the Aleutian Islands, Falls 1976 through 1978.

Date Number Location Observer-Comments

7 Sept. 1976 12 Kiska I. T. Dowel

7 Sept. 34 East Unalga I. W. Hoffman

22 Sept. 2 and 7 Unimak I. J. Nelson

22 Oct. 1977 Unknown Adak I. K. F. Hall, flock heard at night

Mid-Nov. 2 Atka I. M. Snigaroff

Mid-Dec. 2 Atka I. M. Snigaroff

25 Aug.- 1-3 Agattu I. D. W. Woolington and 14 Sept. 1978 D. R. Yparraguirre

19 Sept. 1 Adak I. T. J. Early

20 Sept. 1 Adak I. A. Eischens

3 Oct. 5-7 Adak I. G. A. Putney and D. Clemens 29

and Unimak by U. S. Fish and Wildlife personnel (J. E. Sarvis pers.

comm.).

Northwest Coast. No Aleutian Canada geese were observed in surveys along the coasts of Oregon, Washington, Vancouver Island and mainland British Columbia, and inland in the Willamette Valley federal refuge complex during the falls of 1975 and 1976 (Table 4). Since that time no verified fall observations of Aleutian geese in these areas have been reported by observers nor have any banded birds been recovered.

Northern California. Crescent City, California, was the location of the northernmost verified records of Aleutian Canada geese south of the Aleutian Islands. The geese were observed passing through the area during October and November. Birds were first sighted in fall 1975 when California Department of Fish and Game warden D. G. Gastineau

(pers. comm.) observed a flock of 100+ Aleutian geese on Castle Rock on

26 October (Table 5). The first record for fall 1976 was 25 October when a group of three was observed grazing on Castle Rock (T. Greener pers. comm.). Birds were observed through 19 November in 1975 and 24

November in 1976. Flocks of as many as 365 Aleutian geese were observed using Castle Rock. A minimum of 14 and 24 different marked individuals were observed in falls 1975 and 1976, respectively.

The route taken by the geese from the northwestern coast of

California to the Central Valley has not been documented; however, geese fitting the description of Aleutians were observed south of the Crescent

City area. A flock of 11 of these geese was observed near Arcata,

Humboldt County, on 17 October 1977 (T. Poole pers. comm.). On 19 and

20 October 1977, flocks of 35 and 40+ "lesser type" Canada geese were 30

Table 4. Unsuccessful Surveys for Aleutian Canada Geese, Falls 1975 and 1976.

Dates Locations

12 Oct. 1975 Oregon coast and offshore rocks, from California border north to Florence, Lane County.a

15 Oct. Baskett Slough National Wildlife Refuge, Polk County, Oregon.

18 Oct. Willapa National Wildlife Refuge, Pacific County, Washington.

24 Oct. Lake Michael area, Ladysmith, British Columbia.

25 Oct. Wetland areas surrounding Duncan, British Columbia.

29 Oct. Grice Bay, Pacific Rim National Park, British Columbia.

30 Oct. Grice Bay, Pacific Rim National Park.

31 Oct. Tofino Inlet and Tofino Airport, Tofino, British Columbia.

4 Nov. Sauvie Island, Multnomah County, Oregon.

5 Nov. Baskett Slough National Wildlife Refuge and Akeny National Wildlife Refuge, Marion County, Oregon.

7 Nov. Oregon coast and offshore rocks from Florence south to Gold Beach, Coos County, Oregon.a

15-16 Oct. 1976 Grice Bay, Pacific Rim National Park.

16 Oct. Tofino Inlet.

20 Oct. Aerial survey, west coast of Vancouver Island, British Columbia, from Grice Bay to Hansen Lagoon.

21 Oct. Aerial survey, coast of Graham Island, British Columbia, from Seal Inlet to Rose Inlet.

23 Oct. George C. Reifel Waterfowl Sanctuary, Delta, British Columbia.

25 Oct. Serpentine Wildlife Area and surrounding private land, Delta, British Columbia.

28-29 Oct. Willapa National Wildlife Refuge. 31

Table 4. Unsuccessful Surveys for Aleutian Canada Geese, Falls 1975 and 1976. (continued)

Dates Locations

30 Oct. 1976 Baskett Slough National Wildlife Refuge.

2 Nov. Oregon coast and offshore rock from Reedsport, Lane County, to Brookings, Curry County. a Offshore rocks viewed with optical equipment from mainland. 32

Table 5. Numbers and Time of Occurrence of Aleutian Canada Geese Present at Crescent City, Falls 1975 and 1976.a

Number of Geese Observed Date 1975 1976

25 October 3 26 100+ 0 27 28 0 29 50 0 30 65 49 31 70+ (30 arrived after dark) 1 November 110 82 2 3 113 365 4 102 195 5 108 99 6 100 126 7 124 8 184+ 127 9 201 10 29 83 11 15 29 12 8 29 13 7 12 14 4 9 15 4 16 11 30 17 12 18 6 0 19 1 20 0 21 22 23 24 30

aObservers included M. Ahl, S. L. Funderburk, D. G. Gastineau, J. Gillen, T. Greener, W. G. Henry, P. B. Rail, W. E. Rodstrom, P. F. Springer, and D. W. Woolington. 33 seen flying upstream from the mouth of the Eel River, Humboldt County, by J. Smith, a local resident (W. G. Henry pers. comm.). The flock on

20 October was heard calling with "voices that were not like cackling

Canada geese." On 9 November 1977, S. W. Harris (pers. comm.) observed a flock of 30 small Canada geese flying north along the beach at the

Mad River County Park north of Arcata. The flock was viewed through binoculars at 200 m. and neck rings were visible on at least four geese.

Wintering Grounds

Sacramento Valley. The presence of Aleutian Canada geese was documented in the Butte Sink area by hunter recoveries in 1975 and by direct observation in 1975 and 1976. In 1975, Aleutians were known present by 11 November when one banded and two unbanded Aleutian geese and four small Canada geese of unknown subspecies (latter birds not available for examination) were shot from a flock of approximately 250,

3.2 km north of Meridian, Sutter County. According to the hunters the geese had flown from the direction of the Butte Sink. On 21 November

1975 a flock of 230 Canadas, primarily Aleutian geese with a few cackling geese, was found on the 833 Reclamation District by P. F.

Springer and the author. At least 10 different marked individuals were observed. The flock was kept under observation until 27 November when they disappeared.

In 1976 at least 887 Aleutian geese were present on the 833

Reclamation District at the time of my arrival on 7 November (Table 6).

A nearby landowner (R. Wilbur pers. comm.) indicated that 250-400 geese had been present since at least 25 October. As virtually no other Canada geese subspecies were in the Sacramento Valley at that time, it was

Table 6. Occurrence and Flock Size of Aleutian Canada Geese in the Butte Sink, Fall 1976.a

Date Number Present Date Number Present.

25 Oct.-6 Nov. "Several hundred present" 20-22 Nov. Observed, no. not determined.

7 Nov. 887 23 Nov. 650 est. b 8 Nov. 900 est. 26 Nov. 1000 small Canadas, mostly Aleutians.

9 Nov. --- 27 Nov.-3 Dec. Aleutians present but number not deter- mined due to large numbers of other 10 Nov. 1000 geese and tall rice stubble.

11 Nov. 1000 est. 4 Dec. 150+

12 Nov. 1250 5-8 Dec. Aleutians present but number not deter- mined due to large numbers of other 13-14 Nov. 1250 est. geese and tall rice stubble.

15 Nov. 1000+ 9 Dec. 0

16 Nov. Observed, no. not determined.

17 Nov. ---

18 Nov. 1000+

19 Nov. 852, incomplete count. a Unless indicated differently, all figures represent Aleutian Canada geese. 34

b Estimate. 35

surmised that the landowner had been observing Aleutians. The flock was

present on the nearby fields of the West Butte and Butte Creek Farms as

well as on the 833 Reclamation District. A peak count of 1250 Aleutian

geese was obtained on 12 November 1976. A total of 101 observations of

77 marked individuals was made during this period (individual sighting rate: range 1-3, mean 1.3). By the last 2 weeks of November the geese began leaving the area. However, adverse viewing conditions prevented accurate determination of their departures. By 9 December 1976 no

Aleutian geese were observed using the Butte Sink.

In 1977 the presence of Aleutian Canada geese in the Butte Sink was first recorded on 15 October when a flock of 18 geese, including at least two marked birds, was observed on the West Butte Farms. The property caretaker indicated that the birds had been present since "the first of the month" (J. Staple pers. comm.).

During winters 1975-76 and 1976-77 the presence of Aleutian

Canada geese in other parts of the Sacramento Valley was recorded by sightings and band recoveries (Table 7). Records south of the Butte

Sink occurred during late November when counts indicated that Aleutian geese were departing the Sink.

A marked Aleutian, seen 7 days earlier in the Butte Sink, was shot on 22 November 1976 near Zamora, Yolo County, 4,8 km to the south.

In the Yolo Bypass, Yolo County, 72 km south of the Butte Sink, a marked Aleutian goose was shot on 21 November 1975; a flock containing marked Aleutians was observed on 27 November 1975; and a marked

Aleutian was shot from a flock of 35 on 12 December 1976. Table 7. Records of Aleutian Canada Geese in the Sacramento Valley, Winters 1975-76 and 1976-77.

Date Number Location Observer-Comments

11 Nov. 1975 7 2.4 km N. of Meridian, 1 banded, 2 unbanded, 4 possible Aleutians shot Sutter County from flock of 250.

15 Nov. 1 2.4 km N. of Meridian Unbanded cripple, captured by hunters; specimen at California Polytechnic State University, San Luis Obispo.

21-27 Nov. 230 Butte Sink, Colusa and Flock under observation. Sutter Counties

21 Nov. 1 Yolo Bypass, Yolo County Band recovery

27 Nov. 22 Yolo Bypass D. Pitts, 7 banded birds.

30 Nov. 12 Delevan NWR, Colusa D. Pitts, 6 banded birds. County

30 Nov. 25-30 & 12 Delevan NWR L. H. Nelson, at least one banded bird in each flock.

7 Nov.-8 Dec. 1976 up to 1250 Butte Sink Major flock under observation probably present since before 25 October

22 Nov. 1 4.8 km N.E. of Zamora, Band recovery Yolo County

12 Dec. 1 Yolo Bypass Band recovery, shot from flock of 35. 36

37

Sacramento-San Joaquin River Delta and Grizzly Island. No

verified Aleutians were observed in my surveys of the Sacramento-San

Joaquin River Delta during winters 1975-76 and 1976-77. However, the

presence of these geese was documented by band recoveries. In 1975 in

Contra Costa County, one banded and two unbanded Aleutian geese were

shot from a flock of six, 4.8 km northeast of Byron on 10 November, and

one banded bird was shot 4.4 km northwest of Oakley on 9 December. In

1976 another banded bird was shot 8 km southwest of Thornton, San

Joaquin County, on 31 October.

Aleutian geese were present at nearby Grizzly Island State

Wildlife Area, during both winters of the study. The geese were first

recorded when a flock of 40 was observed in the sanctuary zone of that

property on 25 November 1975 by California Department of Fish and Game

personnel (C. S. Edon pers. comm.). Although tall vegetation prevented

the observation of leg markers, the geese were identified as leucopareia

because of the presence of neck rings on all birds and comparative size

and configuration. This flock was kept under observation by study and

Department of Fish and Game personnel until 8 February 1976 (Table 8).

The first record of Aleutian Canada geese at Grizzly Island in

winter 1976-77 occurred when a banded bird was shot from a flock of 12-18

on 27 November (Table 8). A flock of approximately 50 was observed 12

December (C. S. Edon pers. comm.). Subsequent investigations determined

the presence of as many as 51 Aleutians, including two marked brood

mates of the goose shot previously on 27 November. Aleutian geese were

observed through 14 January 1977. One of the marked individuals had

been observed repeatedly near Modesto and Los Banos beginning 26 January

1977. Table 8. Aleutian Canada Geese Observed at Grizzly Island Wildlife Area, Winters 1975-76 and 1976-77.8

1975-76 1976-77 Date Number-Comments Date Number-Comments

25 Nov.-10 Dec. 1975 40 Presence determined by DFG personnel 27 Nov. 1976 Unknown, 1 band recovery from flock of 12-18

11-14 Dec. 40 28 Nov.-11 Dec. Status unknown, presumed present

16 40 12-13 Dec. 50 (approx.) presence determined by DFG personnel 19-22 40 14-16 51 25 Dec.-26 Jan. 1976 40 Presence determined by DFG persnnel 17-18 37+ 27 Jan.-5 Feb. No observations, presumed absent by DFG personnel 19 40+

6-8 Feb. 40 20 50

21-22 48

24 27

27 36

28 31 29 48

30 29

.31 14

1-11 Jan. 1977 No observations, status unknown

12 42

14 47-48

15 0

aObservers include G. V. Byrd, E. P.Camilleri, C. S. Edon, R. E. Gill, Jr., J. R. Huddleston, J. T. Loris, P. F. Springer, and D. W. Woolington. 38

39

San Joaquin Valley. No Aleutian Canada geese were observed dur­ ing the almost daily surveys conducted in Merced, Stanislaus, and Fresno

Counties from 27 December 1975 to 6 February 1976. The presence of

Aleutian geese in Merced County was determined, however, by the recovery of three banded birds by hunters from 1 December 1975 to 10 January 1976 near Gustine and Los Banos.

In winter 1976-77, Aleutian Canada geese began moving into the

San Joaquin Valley after their late November-early December departure from the Sacramento Valley. Of five banded birds recovered by hunters in Merced and Stanislaus Counties between 25 November and 25 December

1976, one had been observed earlier that fall in the Butte Sink.

On 7 January 1977 an estimated 1000 Aleutian Canada geese were discovered on the Faith Ranch (Table 9). The Aleutians were part of a mixed flock of 3500 geese frequenting the area. Ranch foreman C.

Barkdull (pers. comm.) indicated the flock had been present since "the last week of December." Due to the compactness of the flock, it was impossible to arrive at accurate daily counts. However, a minimum count of 917 Aleutian geese was made on, 22 January. A total of 272 observations were made on 130 marked individuals during the period

(individual sighting rate: range 1-5, mean 2.1). These observations indicated that the Aleutians present had come from the Butte Sink. Of the 77 marked individuals identified in the Butte Sink in November 1976,

51 (66.2 percent) were either seen on the Faith Ranch or known to have been shot in the intervening areas. Aleutian geese were known to be present on the Faith Ranch through 22 February. Reports by J. Rhea

(pers. comm.) indicated no Aleutians were present during late 40

Table 9. Daily Counts of Aleutian Canada Geese on the Faith Ranch, 25 December 1976 to 7 March 1977.

Date Number Date Number

25 Dec.-6 Jan. Probably present w/large flock 30 Jan. of Canadas 31 7-8 1000+ est. 1 Feb. 750+ 9 2 465+ 10 1000+ est. 3 600 est. 11-12 4-5 13-15 1000 est. 6 160 16-19 7-9 20-21 1000 est. 10 50 22 1000 est. (917 counted) 11-16 23 1000 est. 17 12 24 18-21 25 Observed, no count 22 26 724 23 Feb.-6 Mar. 27 725 7 Mar. 10-15 28

29 Observed, no count 41

February-early March, but L. R. Kludt (pers. comm.) observed 10-15, including one marked individual, on the Faith Ranch on 7 March 1977.

On 12 January 1977 a flock of 35-40 small Canada geese including at least three marked Aleutians was observed near Hughson, 8 km south­ east of Modesto (C. Fontane pers. comm.). It was unknown whether these geese came from the main flock at the Faith Ranch. A banded Aleutian goose was found dead by a hunter 12.8 km north of Los Banos on 19

January 1977.

On 24 January a flock of 280 Aleutians, including 26 marked individuals, was observed in the pasturelands of the Nemethi Land and

Cattle Company, 3.2 km northeast of Los Banos (Table 10). Of the banded birds, 14 (53.8 percent) had been observed at the Faith Ranch earlier in the month. Time of last previous sighting ranged from 2 to 14 days

(mean = 10.1 days). Ranch foreman B. Gomez (pers. comm.) indicated the flock had been present in the pastures for "about a week.",

A flock of 64 or more Aleutians, including at least two marked individuals, was observed at the Merced National Wildlife Refuge on 26

January 1977 (L. A. Littlefield pers. comm.). This coincided with a reduced count of 207 Aleutians at the Nemethi Ranch.

From the time of initial observation the number of Aleutians and incidence of marked individuals seen at the Nemethi Ranch increased, coinciding with the decline in flock size of Aleutians at the Faith

Ranch. One hundred-forty-four marked individuals were observed a total of 807 times during the period (individual sighting rate: range 1-18, mean 5.6). Flock counts and band observations indicated the geese were moving to the Nemethi Ranch after departure from the Faith Ranch. Of the 130 individuals identified on the Faith Ranch during January and Table 10. Daily Counts of Aleutian Canada Geese on the Nemethi Ranch and Adjacent Areas, 17 January to 13 March 1977. .

Date Number-Comments Date Number-Comments

17-23 Jan. Presence of 200+ small anada geese 16 Feb. ---- indicated by ranch foreman 17 1090 24 280a 18 1518 small Canadas 25 Observed, no. not determined 19 1079 small Canadas, Aleut. departure noted 26 207 (64+ at Merced NWR) 20 1310 small Canadas, Aleut. departure noted 27 ---- 21 1227+ small Canadas 28 393 22 Observed, no. not determined 29 ---- 23 1154 small Canadas 30 300+ 24 Observed, no. not determined 25 800 est. 31 ---- b 1 Feb. 350 est. 26-27 ---- 2 355 28 800 est. 3 400+ 1-4 Mar. 1500 small Canadas 4-5 ---- 5 Major departure noted 6 900 est. 6 ---- 7 900+ 7 Observed, no. not determined 8 1040 small Canadas 8-11 40 9 1000 small Canadas 12 40, departure of all birds in p.m. 10 900 est 13 0 11 915+ 12 943 13 1000 small Canadas 14 Observed, no. not determined 15 1096

aUnless otherwise indicated, number indicates Aleutian Canada geese. 4 b 2 Estimate 43

February 1977, 108 (83.1 percent) were observed at the Nemethi Ranch.

One marked individual known to be on the Faith Ranch on 14 January was observed on the Nemethi Ranch on 26 January, but was sighted again on the Faith Ranch on 29 January and 3 February and then returned to the

Nemethi Ranch where it was sighted on 12 February. However, the move­ ment rate, back and forth, between these locations was not determined.

The number of Aleutians present at the Nemethi Ranch peaked at approx­ imately 1100 on 15 February. At that time varying numbers of up to

600 cackling Canada geese joined the flock. Heat wave distortion coupled with the compactness of the flock and the presence of other

Canada geese made accurate counts of Aleutians not always obtainable.

Aleutian Canada geese were known present at the Nemethi Ranch through

12 March 1977.

Table 11 provides a summary of the records of Aleutian Canada geese in the San Joaquin Valley during winters 1975-76 through 1976-77.

Other use areas. A family group of six leg-marked Aleutian

Canada geese was known present on the Salton Sea National Wildlife

Refuge, Inyo County, on 3 December 1975. One of the juvenile birds was shot on that date. The remaining five birds were seen on the refuge until 10 December (D. V. Tiller pers. comm. to P. F. Springer). The three juveniles from this group were later recovered by a hunter on 20

December 1975, 30 km south of San Luis Rio Colorado, Sonora, Mexico. An unrelated marked bird was recovered from a flock of two on 12 December

1975, 2 km north of Havasu National Wildlife Refuge, Mohave County,

Arizona. A single possible Aleutian was observed associating with other species of geese on the Salton Sea National Wildlife Refuge on 13, 21, 23

January and 5-6 March 1976 by D. V. Tiller (pers. comm. to P. F. Springer). 43

February 1977, 108 (83.1 percent) were observed at the Nemethi Ranch.

One marked individual known to be on the Faith Ranch on 14 January was observed on the Nemethi Ranch on 26 January, but was sighted again on the Faith Ranch on 29 January and 3 February and then returned to the

Nemethi Ranch where it was sighted on 12 February. However, the move­ ment rate, back and forth, between these locations was not determined.

The number of Aleutians present at the Nemethi Ranch peaked at approx­ imately 1100 on 15 February. At that time varying numbers of up to

600 cackling Canada geese joined the flock. Heat wave distortion coupled with the compactness of the flock and the presence of other

Canada geese made accurate counts of Aleutians not always obtainable.

Aleutian Canada geese were known present at the Nemethi Ranch through

12 March 1977.

Table 11 provides a summary of the records of Aleutian Canada geese in the San Joaquin Valley during winters 1975-76 through 1976-77.

Other use areas. A family group of six leg-marked Aleutian

Canada geese was known present on the Salton Sea National Wildlife

Refuge, Inyo County, on 3 December 1975. One of the juvenile birds was shot on that date. The remaining five birds were seen on the refuge until 10 December (D. V. Tiller pers. comm. to P. F. Springer). The three juveniles from this group were later recovered by a hunter on 20

December 1975, 30 km south of San Luis Rio Colorado, Sonora, Mexico. An unrelated marked bird was recovered from a flock of two on 12 December

1975, 2 km north of Havasu National Wildlife Refuge, Mohave County,

Arizona. A single possible Aleutian was observed associating with other species of geese on the Salton Sea National Wildlife Refuge on 13, 21, 23

January and 5-6 March 1976 by D. V. Tiller (pers. comm. to P. F. Springer). Table 11. Records of Aleutian Canada Geese in the San Joaquin Valley, Winters 1975-76 and 1976-77.

Date Number Location Observer-Comments

1 Dec. 1975 1 banded Lne Tree Duck Club, 6.4 km E Gustine, Hunter recovery of single bird Merced County.

20 Dec. 1 banded Los Banos sewage treatment ponds, 3.2 Illegal hunter recovery of single km NE of Los Banos, Merced Co. bird, location reported 1 year after recovery.

10 Jan. 1976 1 banded Hollister Land and Cattle Company, 9.8 Found dead by hunter, no apparent km SE of Gustine wounds.

25 Nova 1 banded 8 km NE of Delhi, Merced County Hunter recovery of single bird.

28 Nov. 1 banded Wolfson Ranch, 0.4 km W of San Luis NWR, Hunter recovery Merced Co.

10 Dec. 1 banded Bogetti Ranch, 14 km SW of Modesto, Hunter recovery, bird last observed in Stanislaus Co. Butte Sink 21 November 1976.

15 Dec. 4 banded Merced NWR, Merced Co. R. M. Anglin, individual markers not identified.

25 Dec. 2 banded Newman Gun Club, 9.6 km NW of Gustine Illegal hunter kill, single bird, and 1 unbanded 2 taken from flock of 25.

7 Jan.- Main flock Faith Ranch, Stanislaus Co. As many as 1000 Aleutians observed, 22 Feb. 1977 probably present since 25 Dec.

12 Jan. 35-40 Hughson, Stanislaus Co. F. Fontane, at least three marked

birds. 44 Table 11. Records of Aleutian Canada Geese in the San Joaquin Valley, Winters 1975-76 and 1976-77. (continued)

Date Number Location Observer-Comments

13 Jan. 1977 4 unbanded Wolfson Ranch, Los Banos D. W. Woolington

19 Jan. 1 banded Lonesome Mallard Duck Club, 12.8 km N of Found dead by hunter, wounds evident. Los Banos

24 Jan.- Main flock Nemethi Ranch, 3.2 km NE of Los Banos As many as 1100 Aleutians observed, 12 Mar. probably present since 17 Jan.

26 Jan. 64 Merced NWR L. A. Littlefield, at least two marked birds.

7 Mar. 10-15 Faith Ranch L. R. Kludt, one marked bird. 4 5 46

No Aleutian geese were recorded in the southern California­

Arizona-northern Mexico area during winter 1976-77. An apparent family

group of four Aleutians, including one marked bird was seen by various

U. S. Fish and Wildlife Service personnel from 12 Novebmer 1977 to 6

January 1978 on the Salton Sea National Wildlife Refuge (P. F. Springer

pers. comm.). Of this group, one bird was shot by a hunter on 12

November and another was crippled and eventually disappeared.

Spring Migration

Departure from the Central Valley. The exact route taken from

the main wintering areas to the northwest California coast has not been

determined. Birds were noted leaving the Los Banos area from 19

February to 12 March 1977 (Table 10). Departing flocks fromed V-

formations, rose to 300-400 m. altitude and flew in a northwest bearing.

These departures occurred both during day and night. By 8 March 1977,

only 40 Aleutian geese, including three marked birds, were observed in

the Los Banos area. These birds were observed departing from the area

on 12 March (J. C. Cawthorn pers. comm.).

Observations indicated a rapid flight by at least some of the

birds from Los Banos to the staging area at Crescent City. Of 50 marked

birds known present on the Nemethi Ranch on 4 March 1977 and believed to have departed on 5 March, three were known to be present at Crescent

City on 6 March, and 37 (74 percent) had been observed by 10 March. One marked individual known by Cawthorn to have departed Los Banos at 1845 hrs on 12 March was observed at 0730 hrs the following morning at

Crescent City. However, although the last birds were known to have 47 left the Nemethi Ranch by 12 March, the peak count at Crescent City was not obtained until 25 March.

An unknown number of geese return via the Sacramento Valley. A group of six unbanded birds bearing Aleutian characteristics was observed within a flock of 4500 mixed Canada geese on 21 February 1976 in the 833

Reclamation District. On 12 March 1978 a group of 18 Aleutian geese, including three marked individuals whose leg bands were not read, was observed on the 833 Reclamation District (L. H. Nelson pers. comm.).

The duration of time these geese were present in the Butte Sink or if they had come from the main use areas of the San Joaquin Valley were not determined.

Occurrence in Humboldt County. Aleutian Canada geese were re­ corded migrating northward along the Humboldt County coastline during

February and March 1977 and 1978 (Table 12). One banded bird, shot illegally from a flock of six on 20 February 1977, had last been seen on

22 January at the Faith Ranch.

Crescent City staging grounds. After departure of southward migrating Aleutian geese in November, none of the birds were seen in the Crescent City area until January. First records were 12 Aleutians on Castle Rock on 10 January 1976 (W. E. Rodstrom pers. comm.) (Table 13) and 14-18 Aleutians on Castle Rock as well as 7 Aleutians on 21-km­ distant Prince Island on 11 January 1977 (W. G. Henry pers. comm.)

(Table 14). Although the number of Aleutian geese in the area increased steadily after those dates, less than 100 were observed before 12

February 1976 and 1 February 1977. Major movement of the population into the Crescent City area occurred during late February and early March, Table 12. Records of Verified and Probable Aleutian Canada Geese along Coastal Humboldt County, February and March 1977 and 1978.

Date Number Location Observer-Comments

20 Feb. 1977 1 banded Humboldt Bay (South Bay) Brd illegally killed from flock of six by black brant ' hunter, reported by W. G. Henry.

19 Feb. 1978 25-30 1.6 km W of Arcata J. Morlan, probable Aleutians

20 Feb. 45-50 Humboldt Bay (South Bay) Unidentified brant hunter, probable Aleutians flying south at 100 m altitude, 0700-0800 hrs.

20 Feb. 40 Humboldt Bay (North Bay) S.W. Harris et al., small unidentified Canada geese flying north, 0730 hrs.

20 Feb. 35 Humboldt Bay Approx. 90 brant hunters; "lesser-type" with visible neck rings flying north over South Spit at 35 m altitude, 1030 hrs.

22 Feb. 50-60 Mouth of Eel River T.A. Pearl, "Aleutian-type" flying north along coast at 35 m altitude, 1100 hrs.

22 Feb. 71 Humboldt Bay (South Bay) D. W. Woolington and J. G. Mensik, probable Aleutians flying north at 200 m altitude, 1245 hrs.

4 Mar. 2 Mad River Slough, Arcata S. Laymon, probable Aleutians. 48 49

Table 13. Daily Counts of Aleutian Canada Geese Observed at Crescent City, Spring 1976.a

Date No. of Birds Date No. of Birds Date No. of Birds

10 Jan. 12 29 Feb. 258 (I) 3 Apr. 896 11 12 1 Mar. 447 4 791 (I) 13 12 2 448 5 541 (I) 14 12 3 - 6 175 (I) 15 12 4 351 7 747 (I) 17 20+ 5 361 9 850+ 18 33 6 379 10 857 (I) 21 78 7 351 11 900 22 84 8 479 12 876 23 80 9 457 13 832 25 84 11 506 14 794 27 71+ 12 717 15 754 3 Feb. 77+ 13 669 16 788 4 84 14 702 (I) 17 652 6 78+ 15 760 18 746 8 80 16 740 19 580 9 86 17 250+ (I) 20 676 12 137 18 100+ (I) 21 606 14 173 19 673 22 467 15 146+ 22 669 (I) 23 256 (I) 18 150+ 23 851 24 214 19 258 25 832 25 239 20 264 28 652 (I) 26 205 (I) 21 304 29 783 (I) 27 285 900 28 267 (AM) 22 344 b 30 23 224 ( ) 31 889 14 (PM) 25 308 1 Apr. 811 (I) 29 14 (AM) 28 300 2 844 (I) 0 (PM) 1 May 0 aObservers include J. Gillen, T. Greener, G. Lester, W. E. Rodstrom, P. F. Springer, and D. W. Woolington. b (I) indicates incomplete counts. 50

Table 14. Daily Counts of Aleutian Canada Geese Observed at Crescent City, Spring 1977.a

Date No. of Birds Date No. of Birds

11 Jan. 21-25 8 Mar. 582

13 15 9 860

19 28 (may include dusky Canada 10 836 (AM), 1012 (PM) geese) 12 790 (I) 20 10 13 1004 21 10 14 997 22 8 15 1000 est. 25 46 16 1041 29 10-15 17 997 (I) 30 74 (including dusky Canada geese) 18 688 (I)

1 Feb. 117 (including dusky Canada 19 1055 geese) 20 926 (I) 4 21 21 1042 5 63 (including dusky Canada geese) 23 943 (I)

8 46 25 1150

12 64 26 (I)

14 63 28 966 (I)

16 112 29 (I) b 18 24 (I) 30 1101

19 122 31 (I)

20 136 1 Apr. 1010 (I)

23 340 (AM), 543 (PM) 2 968 (I)

24 596 3 1059

25 565 4 --- (fog) 51 Table 14. Daily Counts of Aleutian Canada Geese Observed at Crescent City, Spring 1977.a (continued)

Date No. of Birds Date No. of Birds

5 Apr. --- (fog) 28 Apr. 60

6 983 29 79

8 998 30 77

11 688 (I) 1 May 77

12 1053 2 23

13 1040 3 22

14 1021 4 22

15 949 (I) 5 23

16 1072 6 22

17 1027 7 3

18 1025 8 3

19 950 9 4

20 Major depart. in AM 10 , 3

21 489 (AM), 350 (PM) 11 4

22 80 12 2

23 82 13 3

24 79 15 2

25 66 16 2

26. 70 17 2

27 68 20 0 a Observers include T. Greener, M. D. Griswld, W. G. Henry, G. Lester, P. F. Springer, and D. W. Woolington. b (I) indicat26incomplete counts. 52

with 500+ present by 11 March 1976 and 23 February 1977. Peak counts of

Aleutian geese present were 900 on 30 March 1976 and 1150 on 25 March

1977.

In spring 1976 a total of 692 observations were made on 110

color leg-marked geese (individual sighting rate: range 1-19, mean 6.3)

(Table 15). In spring 1977 a total of 1410 observations were made on

303 marked geese (individual sighting rate: range 1-15, mean 4.7)

(Table 15). Of the previously marked birds observed at Crescent City in spring 1977, 126 (85.1 percent) had been seen earlier that winter in the Central Valley.

Following the peak count in spring 1976, the number of Aleutians present appeared to remain constant, at approximately 900 birds, until

13-14 April at which time counts indicated about 100 geese left. On 19

April a flock of 70 to 80 were observed flying northward. After that date, departure from the area occurred daily. Departing flocks would last be observed flying north or northwest (3600-3150) over the ocean.

By the morning of 28 April only 267 Aleutians were counted at Crescent

City, and all but 14 departed the area that day. The remaining 14

Aleutians were last seen in the area on 29 April.

In 1977, daily population counts fluctuated greatly following the 25 March peak of 1150 Aleutians. The variation in numbers was possibly the result of decreased visibility due to fog and stormy weather. By 16 April at least 1072 Aleutians were present. The major migrational movement occurred early in the morning of 20 April when

500+ Aleutians were observed departing northward. On 21 April a morning count of 489 Aleutians was recorded, but by that evening only 350 were present. The 132 geese observed leaving that day flew northwest over Table 15. Number of Marked Individuals Identified during Observations of Aleutian Canada Geese at Crescent City, Springs 1976 and 1977.

Spring 1976 Spring 1977 Banding Status by Year, Age No. of No. of No. of No. of Class, and Location Banded Individuals Observations Individuals Observations

1974 adults Buldir 14 116 12 51

1974 goslings Buldir 17 84 14 70

1975 adults Buldir 15 135 9 54

1975 goslings Buldir 21 247 9 65

1976 adults Crescent City 32 88 25 143

1976 yearlings Crescent City 11 22 10 52

1976 adults Buldir 14 93

1976 goslings Buldir 55 409

1977 adults Crescent City 80 213

1977 yearlings Crescent City 75 260

Total 110 692 303 1410 53 54

the ocean for 1.5 km, then turned north and continued out of sight.

On the evening of 22 April only 80 birds remained. The number was further reduced to 23 on 2 May and 4 on 9 May. Two birds, including a flightless cripple, were last noted on 19 May.

North of California. No verified records of Aleutian Canada geese were obtained in Oregon, Washington, or British Columbia during springs 1976 and 1977. I observed no Aleutians during the surveys conducted on and near Willapa National Wildlife Refuge, Ilwaco,

Washington, on 26-30 April 1976 and 22-24 April 1977. J. M. Welch (pers. comm.) reported observing small groups of Canada geese bearing Aleutian characteristics on 16-21 April 1977 near Ilwaco, Washington, but was unable to positively identify the presence of leg markers or neck collars.

The exact route from northern California to the breeding grounds at Buldir was not determined. The first spring records of Aleutian geese north of California occurred in the central Aleutian Islands

(Table 16). The earliest spring record of Aleutian Canada geese was a

1 April 1978 sighting of a single bird on Atka Island reported by M.

Snigaroff (pers. comm. to T. J. Early). However, it is possible this bird may have overwintered in the area rather than have returned from the California wintering grounds (see Fall Migration).

Of the 12 spring sightings of Aleutian Canada geese reported in

1975 to 1978, 8 (66.7 percent) occurred between 7 and 25 May. The June

1977 reports from Amchitka all occurred within 4 days and may represent the same group of birds. Two sightings occurred west of Buldir on 25

May 1975 and 13 May 1978. Table 16. Observations of Migrating Aleutian Canada Geese in the Aleutian Islands, Springs 1975 through 1978.

Date Location Number Observer

7 May 1975 At sea near Kanaga I. 28 J. L. Trapp and G. A. Putney

25 May At sea 72 km SW of Buldir Island 5 H. Ogi

7 May 1976 Amchitka I. 21 R. P. and S. Schulmeister

17 May Amchitka I. 1 R. P. and S. Schulmeister

10 May 1977 Adak I. 2 T. J. Early and L. Viers

13 May Adak I. 2 F. B. Lee and M. A. Spindler

18 May Adak I. 18 C. Hummel

12 June Amchitka I. unk. (heard in fog) J. Coffey and R. Shannon

15 June Amchitka I. unk. (heard in fog) J. L. Martin and G. W. Elison

16 June Amchitka I. 10-20 F. B. Lee et al.

1 Apr. 1978 Atka I. 1 M. Snigaroff

13 May Shemya I. 3 D. Finch 55 56

An Aleutian Canada goose, banded as a gosling on Buldir in 1976, was shot by a Native subsistence hunter on Saint George Island of the

Pribilof Island group on 30 May 1978 (G. L. Hunt pers. comm.). This return represents the first verified record of Aleutian Canada geese on the Pribilof islands. In addition, three Aleutians, including a year­ ling that had been banded in the spring of 1978 at Crescent City, were observed on Saint George Island on 18-19 June 1978 by R. L. Gentry (W. E.

Rodstrom pers. comm.).

Ecology on Main Use Areas

Butte Sink

Localized use patterns. Known use areas within the Butte Sink during the winters of 1975-76 and 1976-77 included the 833 Reclamation

District, West Butte and Butte Creek Farms (Fig. 6). In November 1975,

Aleutian geese fed, loafed, and roosted in the partially flooded fields of the 833 Reclamation District during the daytime, but made regular flights southward away from the property. Attempts to locate their destination point were unsuccessful.

When the Aleutian geese were first observed on 7 November 1976, they spent the days feeding and loafing in the fields of the 833

Reclamation District and the nights roosting in the flooded fields of the West Butte Farms. By 10 November they shifted their daytime use area 1.6 km westward to the Butte Creek Farms. The geese stopped using the West Butte Farms as a roost site on 29 November and thereafter began using as a nightly roost a flooded section of field adjacent to the daytime use area on the West Butte Farms. Aleutian geese were not observed leaving the Butte Sink in fall 1976. 57

Figure 6. Aleutian Canada Goose Use Areas in the Butte Sink, Winters 1975-76 and 1976-77. 58

Food items. Aleutian geese on the 833 Reclamation District picked through the disked lima bean stubble. Both stems and beans were consumed. Birds fed on land and in the water where they tipped up to obtain unknown food items. When the geese were in the Butte Creek Farms, they fed in fields of disked, harvested black-eyed beans and burnt, har­ vested rice. I was able to observe the geese consume the beans but was unable to directly record the consumption of rice due to the height of the stubble.

Relation to other wildlife. In 1975 a minimum of 25 cackling

Canada geese, up to 18 Great Basin Canada geese and 800 whistling swans were observed associating with the Aleutian geese at the 833 Reclamation

District. At the beginning of 1976 observations, 15 cackling geese, 1

Taverner's goose, and 1 lesser snow goose were present with the flock of

Aleutian geese. Varying numbers of as many as 750 white-fronted geese frequented the area during the day. Less than 100 Canada geese of other subspecies were present until 29 November, when more than 3000, mostly cackling geese, began using the area. By the time of the last observa­ tion of Aleutian geese on Butte Creek Farms on 4 December, 12,500 geese, primarily lesser snow, white-fronted, and cackling, were using the same fields. Except for the Great Basin Canadas the geese formed one large flock during the day intermingling freely with the Aleutian geese. Most of the cackling geese used the same roost sites as the Aleutian geese, but the white-fronted, lesser snow, and Ross' geese came from unknown roost sites further to the north and northwest of Butte Creek Farms. As many as 500 whistling swans also used the same fields during the period.

Mallards, pintails, American wigeon, American green-winged teal, wood 59

ducks, and northern shovelers were present in the flooded goose-use

areas, but the numbers were not recorded.

The presence of raptors was a visible disturbance factor.

Turkey vultures and red-tailed hawks flying within 150 m of the flock

caused the geese to flush on four observed occasions. Reactions of the

geese ranged from flying 300 m to the next field (one observation) to settling back to the original use area (three observations). On two occasions a marsh hawk was seen to fly over the Aleutian geese at 20 m altitude but caused no flushing.

Relation to human activity. The waterfowl hunting season was in progress while the Aleutian geese were using the Butte Sink during both falls of the study. Following the discovery of the geese on the 833

Reclamation District on 21 November 1975, the Sacramento Valley Canada goose hunting closure, which had been established at the beginning of the season, was extended on 26 November to include the Butte Sink area

(Fig. 7). This closure was further modified prior to the 1976-77 water­ fowl hunting season. In addition, hunting on the 833 Reclamation

District, West Butte Farms, and Butte Creek Farms was not allowed by the landowners. Hunter trespass was noted on two occasions in 1975 and six occasions in 1976. Other human activity was largely restricted to farm workers, law enforcement personnel, and myself. The only known mortality was seven birds shot during 1975 from a flock flying from the Butte Sink

(see sections on Wintering Grounds-Sacramento Valley and Documented

Mortality). Birds limping from possible shot wounds totaled one in 1975 and three in 1976. 60

Figure 7. Sacramento Valley Canada Goose Hunting Closure and Subsequent Modifications. 61

Grizzly Island

Localized use patterns. In winter 1975-76, Aleutians maintained a daily schedule of feeding and resting during the daytime in a barley field of the sanctuary zone of Grizzly Island Wildlife Area and roosting at night at an unknown location southwest of the property (Fig. 8). The birds would come from the direction of Grizzly Bay prior to dawn between

0600-0700 hours and depart in the same direction sometime after sunset.

The 40 geese remained as a single flock during all observations.

In the winter of 1976, movement by the birds was monitored daily by either E. P. Camilleri or myself from 15-24 and 27-31 December. Each morning the geese flew to the barley field between 0700-0830 hrs. Most arrivals were from an unknown location at least 8 km southwest of the

Wildlife Area, but on three instances the geese came from a 400-ha flooded marsh on the Markstine Farms and Meridian Gun Club.property, 3.2 km to the northeast. If the geese were disturbed for any reason before

1000 hrs, they flew to adjacent sections of the field to continue feed­ ing. When disturbed after 1000 hrs (avg. 1129 hrs). Unlike the previous year, the Aleutians were in a single flock 46.9 percent of the observ­ ations. Flock size during feeding and flight ranged from 6 to 51 (avg.

33).

Food items. Common barley was the predominant plant species in the sanctuary use area and was the primary food item seen being consumed.

In winter 1975-76 the geese grazed the tips of plants that ranged in height from 10 to 49 cm. In winter 1976-77 the geese fed in new planted barley fields that ranged in height from 0 to 8 cm and on the young 62

Figure 8. Aleutian Canada Goose Use Areas in the Grizzly Island Area, Winters 1975-76 and 1976-77. 63 green shoots of volunteer stands of barley that were up to 20 cm in height. There was no water in the barley fields. Geese were observed drinking during mid-day in the private marshland northeast of the sanctuary.

Relation to other wildlife. Cackling, Great Basin, and

Taverner's Canada geese, and white-fronted geese were present in the same fields as the Aleutian geese. In winter 1975-76 less than 250 were present and the Aleutian geese generally remained away from the other birds and always departed the daily use area as a discrete group. In

1976-77 when as many as, 4500 geese were present, the Aleutian geese always fed with or within 100 m of them. Cackling geese would fly with the Aleutian geese to roost sites, away from the sanctuary zone.

Relation to human activity. Geese in the sanctuary zone were relatively free from human disturbance. Only Department of Fish and

Game and study personnel were allowed on that portion of the property.

However, flushing of the geese by single-engine aircraft was recorded on

6 out of 20 days of observations. In one instance, deliberate harass­ ment by diving within 30 m was recorded. Aircraft traffic over the area occurred daily. The Aleutian geese would tolerate fixed-wing aircraft within 50 m altitude. However, any nearby cackling geese would flush at the sign of aircraft within 300 m, and in turn, cause the Aleutian geese to flush.

Two Aleutian geese were known to have been shot in the hunting area of Grizzly Island Wildlife Area during winter 1976-77. Geese flying to the roost site northeast of the property were observed being 64 unsuccessfully fired upon two occasions, and at least one individual was observed limping on the ground from possible shot wounds or an accident.

Faith Ranch

Localized use patterns. Areas of observed usage by Aleutian

Canada geese in winter 1976-77 included the Faith and Mapes Ranches

(Fig. 9). On the basis of one band recovery out of a flock of Canada geese on 10 December 1976, at least some of the birds used the Bogetti

Ranch for an unknown length of time. Use of the Vierra Ranch was docu­ mented by single hunter recoveries of banded Aleutian geese on the adjacent San Joaquin River on 8 January 1977 and the ranch itself on

15 January 1977, but no birds were observed there. The Faith Ranch was the activity center for the geese. The birds roosted on and around a

2-ha pond nightly and at dawn moved to the adjoining pastures to feed.

From 0630 to 0800 hrs, mixed flocks of geese, including Aleutians, regularly flew east, west, and south away from the property. Aleutian geese were observed on the Mapes Ranch, but consistent early morning fog prevented following most flights. From 0830 to 1200 hrs these flocks returned to the Faith Ranch and joined the geese that had remained in the pastures. The birds spent the rest of the day in one to several flocks.

Food items. Aleutian geese fed almost exclusively by grazing in closely cropped, flood-irrigated pastures. Grass and clover comprised

81.4 percent of the ground cover on pastures used by the geese (Table

17), and were the main food items observed being consumed. Fecal droppings consisted primarily of leaf,and stem materials and occasionally clover stolens; however, taxonomic identity of geese passing any given 65

Figure 9. Aleutian Canada Goose Use Areas on the Faith Ranch and Vicinity, Winter 1976-77. 66

Table 17. Composition of Ground Cover in Planted Pastures Used by a Aleutian Canada Geese on the Faith Ranch, Winter 1976-77.a

Range Percent (Percent Standard Species Ground Cover Coverage) Deviation Variance

b Unidentified Grasses 56.6 30-75 10.58 111.99 Kentucky bluegrass Bermuda grass Red fescue Dallis grass Rye grass Other

Clover 24.8 15-40 6.54 42.72 Red clover White clover

Birds-foot trefoil 3.3 0-10 4.51 20.34

Curly dock 13.9 5-30 7.59 57.64

Plantain 0.3 0-5 1.23 1.51

Sedge 0.3 0-10 1.77 3.13

Common dandelion trace 0-trace

Bare ground 0.8 0-25 4.42 19.53

Total 100.0 0-75 a Sample size: 32 plots. b Closely cropped vegetation prevented accurate species identification of grasses. The species are ranked by subjectively determined relative abundance and by occurrence based on ranch seeding program. 67 fecal sample was unknown. On one occasion the geese were observed grazing in a freshly sprouted barley field.

Relation to other wildlife. During January and February 1977 the Aleutian geese were part of a large flock of mixed geese that varied in number from 3500 to 6000. Canada geese were the predominant species, with cackling, Great Basin, and Taverner's being present with the

Aleutians. Varying greatly in number from day to day, up to 500 white- fronted, 300 Ross', and 25 snow geese were also present. The geese, including Aleutians, would associate in one to several large mixed flocks and often intermingled freely with grazing cattle.

Relation to human activity. The waterfowl hunting season was in progress during the December arrival of the geese until 23 January 1977.

Since the owners of the Faith Ranch and hunters on the adjacent Mapes

Ranch agreed not to shoot any small Canada geese, the San Joaquin Valley

Canada goose hunting closure was not extended north of State Highway 132 to include these properties.

Birds on the Faith Ranch spent most days relatively undisturbed.

Human activity was largely restricted to ranch workers, law enforcement personnel, and myself. However, attempted hunter trespass was noted on four occasions. Between 10 December 1976 and 23 January 1977 a total of three banded and four unbanded Aleutians were known to have been shot by hunters within a radius of 5.6 km of the Faith Ranch. Of these, three were recovered on the Faith Ranch: two were shot as they flew from the

Mapes Ranch, and the other was found dead, presumably after having been wounded outside the ranch. During this time a minimum of five Aleutians were observed either limping or with bloodstains. 68

Los Banos

Localized use patterns. When the main flock of Aleutian geese was first observed in the Los Banos area on 24 January 1977, the birds maintained a schedule of feeding in the pastures of the Nemethi Ranch during the day and roosting on the adjacent Los Banos sewage treatment ponds at night. Sometime following that the geese shifted to a different roost site south of Los Banos. This behavior was first observed on 16

February, and on 24 February the roost site was identified as the 15-km­ distant marshes of the Britto Gun Club. Time of morning flights to the daytime use area ranged from 0630 to 0715 hrs. Varying numbers of up to the entire flock would land on city-owned pasture just south of the sewage treatment ponds and then fly to the Nemethi Ranch pastures from 0830 to

1100 hrs. Return to the roost site occurred at an unknown time after sunset (Fig. 10).

Food items. The geese formed closely grouped flocks and grazed over the pastures in the Los Banos area in much the same manner as on the Faith Ranch. Food items known to have been consumed included stems of grasses, and stems, leaves, and stolons of clover. Grasses and clovers composed 77.7 percent of the ground cover in the flood irrigated pastures of the Nemethi Ranch (Table 18). Over 95 percent of the vegetation was less than 2.5 cm in height. The ground cover of the city-owned pastureland south of the Los Banos sewage treatment ponds was

48.7 percent grasses and clovers with red-stemmed fillaree, bur-clover and bare ground being the next most abundant cover types (Table 19). 69

Figure 10. Aleutian Canada Goose Use Areas on the Nemethi Ranch and Vicinity, Winter 1976-77. 70

Table 18. Composition of Ground Cover in Planted Pastures Used by a Aleutian Canada Geese on the Nemethi Ranch, Winter 1976-77.

Range Percent (Percent . Standard Species Ground Cover Coverage) Deviation Variance

b Unidentified grasses 47.5 10-85 19.30 372.43 Fes cues Kentucky bluegrass Mediterranean barley Other

Clover 30.2 0-80 19.06 363.36 White clover Red clover Bur-clover

Birds-foot trefoil 5.6 0-20 6.82 46.49

Curly dock 4.8 0-25 6.08 36.98

Red-stemmed fillaree 1.8 0-25 5.22 27.22

Smartweeds 0.1 0-5 0.67 0.44

Shepard's purse trace 0-trace

Bare ground 10.00 0-55 14.55 211.61

Total 100.00 0-85 a Sample size: 57 plots. b Closely cropped vegetation prevented accurate species identification of grasses. The species are ranked by subjectively determined relative abundance. 71

Table 19. Composition of Ground Cover in Fields Used by Aleutian Canada Geese South of Los Banos Sewage Treatment Ponds, Winter 1976­ a 77.

Range Percent (Percent Standard Species Ground Cover Coverage) Deviation Variance

b Unidentified grasses 31.0 10-40 9.67 93.57 Fes cues Kentucky blue grass Other

Bur-clover 17.7 0-30 8.63 74.52

Red-stemmed fillaree 26.0 15-40 6.87 47.14

Shepard's purse 6.0 0-10 4.31 18.57

Mustard 2.0 0-20 5.61 31.43

Brass buttons 0.3 0-5 1.29 1.67

Bare ground 17.7 0-30 8.62 74.49

Total 100.0 0-40 a Sample size: 15 plots. bClosely cropped vegetation prevented accurate species identification of grasses. The species are ranked by subjectively determined relative abundance. 72

Relation to other wildlife. When the Aleutian geese first began

using the Nemethi Ranch, no other geese were present. By 28 January,

seven cackling geese and one Ross' goose had joined the flock. From

2 to 5 March the number of cackling geese associating with the Aleutian

goose flock increased to a peak of 900. These birds intermingled freely

with the Aleutian geese during day, often forming a single, closely

grouped flock in the feeding area. The Aleutian and cackling geese

would fly in one to several flocks from the roost site. During the day­

time, varying numbers of as many as 4 Ross', 7 lesser snow, and 20 white-

fronted geese were present with the mixed flock of Aleutians and

cackling geese. As on the Faith Ranch, domestic cattle grazed in close

proximity of the goose flock, often within 5 m.

Relation to human activity. Although the area north of Highway

152 (Fig. 10) was closed to Canada goose hunting, Aleutian geese were subjected to hunting pressure. On 20 December 1975 a banded bird was shot by a hunter on the Los Banos sewage treatment ponds. In winter

1976-77 at least one unsuccessful hunting attempt was directed at the

Aleutian geese arriving at the Nemethi Ranch prior to the 23 January close of the waterfowl hunting season (B. Gomez pers. comm.).

During the period of direct observations from 24 January to 12

March 1977 disturbance of the geese was kept at a low level. Access to the Nemethi Ranch was restricted to ranch workers, state and federal wildlife agency personnel, and myself. Worker activity at the sewage treatment ponds was minimal. Any disturbance by work activities on the

Nemethi Ranch simply caused the geese to shift temporarily to a more isolated section of pasture. 73

Crescent City

Localized use patterns. During both falls of the study, Castle

Rock was the principal use area in the Crescent City area. The geese were generally observed on the vegetated flats of Castle Rock where they fed. In fall 1976 a maximum of 30 Aleutian geese was observed on the mainland pastures of Reservation Ranch and adjacent Del Norte County

Airport from 16-24 November.

Geese arriving at Crescent City in January for spring staging initially remained on Castle Rock as the birds had done in the fall. By

18 February 1976 and 14 February 1977 the geese began flying to the main­ land pastures on a daily basis. Tables 20 and 21 present the average daily flight times divided into 5-day increments, and their relationship to sunrise. The initial flights in February generally began 0.5 to 1.5 hours after sunrise, but during March and April most morning flights started before sunrise.

Unless disturbed, most of the geese remained on the mainland during the day. As many as 300 birds returned to Castle Rock between

1500-1800 hrs. During February and early March the remaining geese returned to the roost between 1800 and 1900 hrs, but by 1 April the evening flight began between 1920 and 1950 hrs. Poor light, hazy conditions, and large flock size prevented accurate censusing of evening movement from the mainland.

The Reservation Ranch and adjacent McNamara Field comprised the main daytime use area in 1976 and 1977 (Fig. 11). On calm days the geese would graze on hill tops and exposed grassy flats; however, on stormy or windy days they utilized sites that were protected by tall sedges, trees, 74

Figure 11. Aleutian Canada Goose Use Areas at Crescent City, Springs 1976 and 1977. 75

Table 20. Average Starting Times of Daily Flights from Castle Rock to the Mainland Pastures at Crescent City, Spring 1976.

Avg. Starting Range in Avg. Starting Time of Starting Time of Flights before a Times Number of Dates Morning Flights or after Sunrise of Flights Observations

11-15 Feb. No flights - -

16-20 0803 +74.0 0803 1 3 21-25 0808 +86.0 0630-1100

26-30 0655 +19.0 0640-0710 2

1-5 Mar. 0709 +41.5 0645-0743 4

6-10 0641 +19.0 0633-0648 4

11-15 0615 - 1.0 0604-0628 5

16-20 0558 - 8.8 0545-0608 5

21-25 0541 -17.0 0535-0550 4

26-31 0530 -23.5 0525-0538 4

1-5 Apr. 0518 -23.2 0514-0525 5

6-10 0510 -22.5 0500-0517 4

11-15 0508 -17.4 0502-0514 5

16-20 0455 -23.0 0442-0502 4

21-25 0450 -22.6 0445-0506 5

26-30 0440 -24.5 0438-0442 4 a(+) denotes time in minutes after sunrise, (-) denotes time in minutes before sunrise. Times of sunrise obtained from U. S. Naval Observatory (1976). 76

Table 21. Average Starting Times of Daily Flights from Castle Rock to the Mainland Pastures at Crescent City, Spring 1977.

Avg. Starting Range in Avg. Starting Time of Starting Time of Flights before Times Number of Dates Morning Flights or after Sunrisea of Flights Observations

11-15 Feb. 0842 +107.0 0842 1

16-20 No observations - - -

21-25 0617 -24.0 0617 1

26-30 No observations - - -

1-5 Mar. No observations - - -

6-10 0624 +1.3 0617-0630 4

11-15 0620 +3.5 0615-0625 4

16-20 0608 +0.4 0555-0628 5

21-25 0552 -6.0 0545-0557 3

26-31 0549 -0.6 0542-0552 5

1-5 Apr. 0543 -0.5 0535-0550 2

6-10 0540 +4.5 0529-0550 2

11-15 0508 -17.2 0502-0513 5

16-20 0452 -26.2 0440-0500 5

21-25 0457 -14.0 0435-0525 4

26-30 No flight from roost - - a(+) denotes time in minutes after sunrise, (-) denotes time in minutes before sunrise. Times of sunrise obtained from U. S. Naval Observatory (1977). 77

or ridges. Geese used small ponds and water courses in the pasture

briefly for drinking, bathing, and preening, but spent most of the day­

time hours grazing.

Some Aleutian geese overflew the Reservation Ranch pastures and

proceeded to the pastures of the 4.8-km-distant Bliss Ranch in springs

1976 and 1977. As many as 33 geese, including one banded individual,

were known to use the Bliss Ranch in 1976. This usage level was higher

in 1977, increasing from 79 on 26 March to 217 by 19 April. Observations

of banded birds in 1977 indicated a day-to-day variation in the individ­

uals present at the Bliss Ranch, and individuals would use both the

Bliss Ranch and the Reservation Ranch on the same day.

Food items. Velvet grass appeared to be the main food item.

On one occasion in 1975, geese were seen consuming hay that had been put

in the field for the cattle. In 1976 and 1977 the geese supplemented

their food intake with rolled and whole barley which was used in the

goose trapping operations.

Relation to other wildlife. As many as 25 Dusky Canada geese

were present with the Aleutians on Castle Rock during January and

February in 1976 and 1977. As many as seven cackling Canada geese and

three Taverner's Canada geese associated with the Aleutian flock in

1976 and 1977, and one Ross' goose was present from 4-19 April 1977.

A single peregrine falcon frequented Castle Rock and the adjacent mainland in 1976 and 1977. The falcon was observed stooping on the geese over the mainland on two occasions. No geese were hit, but the geese immediately returned to Castle Rock. A subadult female

Aleutian Canada goose was found being eaten by a red-tailed hawk on 78

23 March 1976 in the pastures of the Reservation Ranch. Examination indicated the possibility the goose had been preyed upon (see Documented

Mortality). The remains of an Aleutian that had been eaten recently by an unknown predator or scavenger was found on the airport property on

9 March 1977.

As many as 800 western gulls were present on Castle Rock during time of use by Aleutian Canada geese. These gulls are larger than the geese and actively displaced them. On three occasions gulls were ob­ served feeding on dead geese. Common ravens, occasionally observed on the mainland feeding areas, appeared to ignore the geese, but geese became alarmed at their presence and moved away. In one instance an adult goose was observed displacing a raven. The geese were observed being flushed by a great blue heron twice.

Relation to human activity. Geese often were observed grazing within 20 m of Federal Aviation Administration buildings on the west side of the airport. On other occasions they fed within 30 m of an adjacent county road and 25 m from a beach access parking lot. Geese continued grazing as vehicles drove past, but birds within 100 m walked away or flushed if vehicles stopped or if people were on foot.

The geese tolerated approach of the study vehicle within 35 m.

Aircraft traffic in and out of McNamara Field was a regular occurrence. Operation of small propeller driven aircraft did not disturb

the geese, but daily landings of commercial, twin-engine, prop-jet

aircraft caused geese within 200 m to flush. Weekly landings of a small

private jet aircraft did not cause flushing of geese 200+ m distant, but

the much noisier take-offs caused most of the geese in the pasture to 79 flush and fly either to the northwestern corner of Reservation Ranch or return to Castle Rock.

Approach of helicopters within 750 m of the pastures caused all the geese to flush and return to Castle Rock. No close misses between aircraft and the geese were observed, nor have any bird strikes been recorded in the past.

No human disturbance of Castle Rock was observed in 1976 and

1977. The geese were generally undisturbed as they fed in the pastures.

My activities occasionally caused the geese to flush to other areas of the pastures. Detonation of cannon net traps during banding activities caused geese near the trapsite to return to Castle Rock and the geese more distant to flush to more isolated parts of the pasture.

Two probable incidents of poaching on the Reservation Ranch pasture were reported by local residents in March and April 1976. In one instance a bird was seen dropping, as if shot, from a flock in flight. High winds prevented the hearing of any gunshots. In the other incident several hundred geese flushed following two shotgun blasts in the immediate area and returned to Castle Rock. In spring 1977 a local resident reported that an unsuccessful poaching attempt by two unknown persons occurred during March. In April, I witnessed a youth unsuccess­ fully shoot at the geese.

Population

Documented Mortality

Documented mortality of Aleutian Canada geese totaled 25 in winter 1975-76 (Table 22) and 32 in winter 1976-77 (Table 23). Marked birds comprised 52.0 percent of this recorded loss in winter 1975-76 and Table 22. Documented Aleutian Canada Goose Mortality, Winter 1975-76.

Mortality Band Juvenile Adult Type Status Male Female Unknown Male Female Unknown Total

Hunter Kill Banded 2 3 1 1 4 - 11 (44%) Unbanded - - 1 - - 8 9 (36%)

Disease Banded ------Unbanded - - - -

Trapping loss Banded - - -- 1 - 1 (4%) Unbanded -- - - 1 (4%)

Unknown Banded 1 - - - - - 1 (4%) Unbanded -- - 1 2 (8%)

Total 3 (12%) 4 (16%) 2 (8%) 1 (4%) 6 (24%) 9 (36%) - 25 (100%) 8 0 Table 23. Documented Aleutian Canada Goose Mortality, Winter 1976-77.

Mortality Band Juvenile Adult Type Status Male Female Unknown Male Female Unknown Total

Hunter kill Banded 55a - 1 3 ... 13 (40.6%) Unbanded 2 1 - - 1 2 6 (18.8%)

Disease Banded - - - 1 - - 1 (3.1%) Unbanded 1 - - - 1 - 2 (6.3%)

Trapping loss Banded -- - - 1 ... 1 (3.1%) Unbanded 1 - --- 3 4 (12.5%)

Unknown Banded ------Unbanded - - - -- 5 5 (15.6%)

Total 9 (28.1%) 5 (15.6%) - 2 (6.3%) 6 (18.7%) 10 (31.3%) 32 (100%) a Includes one bird shot illegally on 20 February 1977 by black brant hunter. 81

82

46.8 percent in winter 1976-77. Composition by age class for the two winters was 40.4 percent juvenile, 26.3 percent adult, and 33.3 percent unknown age.

Hunting loss. Hunter kill documented through hunter reports and direct recovery by state and federal personnel or myself totaled 80.0 percent of the documented mortality in winter 1975-76 and 59.4 percent of the documented loss during winter 1976-77. During the first winter of the study, 45 percent of the documented hunter kill was in the

Sacramento Valley during November (Table 24). However, most of those birds were killed by a single hunting party. In the second winter, 68.4 percent of the documented kill occurred in the San Joaquin Valley from

25 November 1976 to 23 January 1977.

Of known-age, documented hunter kills, 7 (58.3 percent) were juvenile birds in winter 1975-76 and 12 (70.6 percent) were juvenile in winter 1976-77. Using the juvenile vulnerability quotient for banded birds as described in Hanson and Smith (1950) shows that juveniles were

1.17 times as susceptible to hunting pressure as adults during the two winters of the study (Table 25).

Disease. No losses from disease were documented for winter

1975-76. In winter 1976-77, 9.4 percent of the documented loss was attributed to disease. An avian cholera outbreak occurred on the Faith

Ranch from 14 to 27 January 1977. The focal point appeared to be the

2-ha pond where the Aleutian geese and other birds were roosting at night. Two Aleutian Canada geese were found dead there and tested positive for avian cholera. The leg band and body feathers of a third probable victim was found at the roost site. A total of 62 birds of Table 24. Geographic and Temporal Composition of Documented Hunting Mortality of Aleutian Canada Geese, Winters 1975-76 and 1976-77.

Winter 1975-76 Winter 1976-77

Documented Loss Documented Loss Location Date No. Percent Date No. Percent

Sacramento Valley a b Outside closure 11-21 Nov. 9 (45.0) 22 Nov.-12 Dec. 2 (10.5) Inside closure

Sacramento-San Joaquin River Delta, Suisun Marsh 10 Nov.-9 Dec. 4 (20.0) 31 Oct.-15 Dec. 3 (15.8)

San Joaquin Valley Outside closure 25 Nov.-23 Jan. 7 (36.8) In closure prior to 15 Dec. 1 Dec. 1 ( 5.0) 28 Nov.-10 Dec. 2 (10.5) In closure after 15 Dec. 20 Dec. 1 ( 5.0) 25 Dec.-19 Jan. 4 (21.1)

Southern California, Arizona, 5c and Mexico 3-20 Dec. (25.0)

Humboldt Bay 20 Feb. ( 5.3)

is Total 20 (100.0) 19! (100.0)

aClosure refers to Canada goose hunting closure zones. b Seven of these birds shot by one party and one additional bird found in same field 4 days later. 8 3 cFour of these from same family group, three of which were shot by one party. 84

Table 25. Juvenile Versus Adult Vulnerability to Hunting of Aleutian Canada Geese Calculated by Band Recoveries during Winters 1975-76 and 1976-77.a

Number of juveniles recoveredb Number of juveniles bandedc a V = Number of adults recovered b Number of adults bandedc

13 145

V 3 39

V = 1.17 a Juvenile Vulnerability Quotient from Hanson and Smith (1950). b Number of recoveries occurring within first year of banding. c Hanson and Smith used the total number of adults and juveniles banded in trapping operations in the wintering areas to calculate the quo­ tient. Because of differential breeding ground mortality, the number of adults and juveniles banded is adjusted to the best estimate of the number alive just prior to fall migration. For the purposes of this equation, the number of juveniles banded in 1975 and 1976 is an esti­ mate of goslings surviving until just prior to fall migration, based on the known minimum 2 percent mortality from time of banding to fledging recorded in summer 1976. For the purpose of the equation the number surviving from time of banding to just prior to fall migration, based on known 0 percent mortality recorded in summer 1977. (Byrd and Woolington unpubl. MS.). 85 various species were picked up during cholera abatement activities.

After positive diagnosis of the initial birds sent to the California

Department of Fish and Game Disease Laboratory and the National Fish and Wildlife Health Laboratory, it was assumed that all dead birds with no sign of wounds had died of avian cholera. The loss of Aleutian geese may have been greater than that documented because, of the intermediate- sized and small Canada geese recovered, 16 (64.0 percent) consisted only of small unidentified wings.

Trapping mortality. Spring banding at Crescent City accounted for 8.0 percent of the documented mortality in winter 1975-76 and 15.6 percent of the documented mortality in winter 1976-77. However, direct comparison of this mortality factor with overall documented mortality inflates the impact of banding mortality because, unlike trapping casualties, not all the losses due to other mortality factors were documented. In spring 1977, two geese became paralyzed and subsequently died as a result of trapping operations. In 1977, three geese became paralyzed but were released after recovery, and five geese died from injuries sustained in trapping. On-site trapping casualty rate per bird handled was 3.0 percent in 1976 and 2.1 percent in 1977.

Unknown causes. Losses due to unknown mortality factors accounted for 13.0 percent of the documented mortality during winter

1975-76 and 15.6 percent in 1976-77. A juvenile female was eaten by a red-tailed hawk on 23 March 1976 on the Reservation Ranch. Examination of the carcass by the National Fish and Wildlife Health Laboratory showed no sign of disease, poisoning, or an excessive parasite load; however, membranes of the gizzard were shredded and hemorrhagic and the 86 intestines had enteritis. Stumps of the torn out pectoral muscles were

hemmorhagic, indicating predation as a probable cause of death. On 9

March 1977 the freshly eaten remains of another goose was found in the

same area. However, the cause of death was not discernable. During

surveys of Castle Rock by P. F. Springer, an Aleutian-goose. presumed to

have died in the spring of 1976, of unknown causes, was found on 19

October 1976. Four Aleutian geese that died of unknown causes in spring

1977 were found on 11 May 1977. An additional Aleutian goose with a

broken wing was sighted on the 11 May 1977 search of Castle Rock but was

not captured.

Known Survival

A total of 3566 observations of banded individuals was made from

22 November 1975 to 24 April 1977. These sightings plus band recoveries

made it possible to determine at some time during the study the status of

72.7 percent of the 359 geese that had been marked from 1974 to 1976. In

April 1977 the current status of 53.8 percent of the marked geese was

known. The life status of marked birds throughout the study is listed by

banding and age class in Table 26. Birds known to be alive through direct

observation represented the minimum number actually remaining in the popu­

lation. However, because of the intensity of band observations and the

pattern of resighting of marked individuals it was assumed that almost all

of the marked geese not recorded by observation or recovery (unknown

status) were, in fact, dead by the end of the study period. This

assumption is supported by the fact that of 72 marked birds known to

have been alive in April 1976, by either sightings at that time or later records, only 4 (5.5 percent) were recorded at a date later than

that spring. Also, no previously marked birds that had not been Table 26. Status of Harked Aleutian Canada Geese from October 1975 to April 1977 Based on Band Observations and Recoveries.

Date and Location of Harking

1974-Buldir 1975-Buldir 1976-Crescent City 1976-Buldir Adult�Gosling Adult�Gosling Adult Juvenile�- Adult�Gosling Known No.b �Percent No. Percent No. Percent No. Percent No.�Percent No. Percent No. Percent No. Percent Date Status (33) (77) (21) (43) (37) (18) (18) (124)

Oct. 1975 Live 15 45.4c 21 27.3 18 85.7 27 62.8 Dead 2 6.1 6 7.8 - 1 2.3 Unk. 16 48.5 50 64.9 3 14.3 15 34.9

Jan- 18, 1976 Live 14 42.4 21 16 76.2 21 48.8 Dead 3 9.1 6 2 9.5 7 16.3 Unk. 16 48.5 50 3 14.3 15 34.9

Apr. 1976 Live 14 21 16 21 37 100 18 100 Dead 3 6 2 7 - - Unk. 16 50 3 15 - -

Sept. 1976 Live 14 18 23.4 12 57.1 11 25.6 35 94.6 10 55.6 18 100 96 92.3 Dead 3 6 7.8 2 9.6 7 16.3 - - - - - Unk. 16 53 68.8 7 33.3 25 58.1 2 5.4 8 44.4 - 8 7.7

Oct. 1976 Live 14 18 11 52.4 10 23.2 32 86.5 10 17 94.4 86 82.7 Dead 3 6 2 9.5 7 16.3 - - - - - Unk. 16 53 8 38.1 26 33.8 5 13.5 8 1 5.6 18 17.3

Jan.�� 23, 1977 Live 13 39.4 16 20.8 9 42.9 9 20.9 31 83.8 10 14 77.8 72 69.2 Dead 4 12.1 8 10.4 2 9.5 7 16.3 - - - 2 11.1 8 7.7 Unk. 16 48.5 53 68.8 10 47.6 27 62.8 6 16.2 8 2 11.1 24 23.1

Apr.�1977 Live 12 36.4 16 9 9 28 75.7 10 14 62 59.6 Dead 5 15.1 8 2 7 - - - 2 9 8.7 Unk. 16 48.5 53 10 27 9 24.3 8 2 33 31.7 aSept. date represents status on breeding grounds prior to fall migration; Oct. dates represent time of initial arrival on wintering grounds; Jan. 18 and Jan. 23 represent date of close of California general waterfowl seasons; Apr. dates represent time immediately prior to spring return to the breeding ground. b Numbers originally banded shown in parentheses. c Percentages are not repeated at subsequent dates unless a change in status occurred. 87 88 observed in winter 1975-76 were recovered by hunters during the following winter.

Out of an assumed minimum of 54 marked adults known to have been alive in the population in September 1975, 51 (94.4 percent) survived until April 1976. Differences within this group in class survival among birds banded as adults in 1974, goslings in 1974, or adults in

1975 were not found to be significant when subjected to Chi square analysis (p> 0.05). Birds banded as goslings in 1975 had a lower

September-1975-to-April-1976 survival rate (48.8 percent) than the adults banded during that same time period (76.2 percent), but the results were not found to be significant (p> 0.05) (Table 26).

In September 1976 a minimum of 118 adults that had been marked and 96 marked goslings were known present in the population. By April

1977, 98 (83.1 percent) of the marked adults and 62 (64.6 percent) of the marked goslings were known to be alive (Table 26). As in the previous winter, there was no significant difference in survival among the adult class birds (p > 0.05). Among the banded sample of different age class birds alive in September 1976, goslings banded in 1976 had the lowest survival rate to April 1977. However, this difference was not found to be significant (p> 0.05). There was no significant difference in survival rates of marked birds of combined age classes between the winters 1975-76 and 1976-77 (p >0.05).

Population Levels

Fall 1975. No direct population counts were obtained in fall

1975 because contact with the main segment of the flock had not been established. Maximum counts of Aleutian Canada geese were 201 at Crescent City on 9 November and 230 at the Butte Sink 21-27 November. 89

Spring 1976. The peak count of 900 Aleutian Canada geese at

Crescent City on 30 March was thought to represent almost the entire population. Observations of banded birds indicated there was an accumulation of birds rather than passage through the staging area and replacement by others. Of 67 previously marked birds seen at Crescent

City in spring 1976, 66 (98.5 percent) were identified before the peak count on 30 March; and of these birds, 57 (86.4 percent) were known present after 30 March (Table 27). Since that time only five marked birds (6.4 percent of the known population) that were present in the population in March and April 1976 but not seen at Crescent City, were recorded: three being observed later at Buldir during summer 1976 and ultimately at Crescent City in Spring 1977, one being observed once on

Buldir in summer 1976, and one being recovered by a hunter in December

1977 (Yparraguirre 1978).

The ratio of banded to unbanded birds was used to calculate a spring population estimate based on the Lincoln Index. Using observa­

tions from 5 to 28 March 1976 and the number of birds marked prior to

spring 1976 versus total capture in banding activities in spring 1976

provides an overall ratio of 120 marked to 1363 unmarked birds. Given

the 67 banded individuals seen at Crescent City and the 5 observed at later dates, 72 marked birds were assumed in the population at that

time. The population was calculated as follows:

nM where N is the spring population N M is the total number of marked individuals n is the total birds observed for markers m is the number of marked birds observed

N = 1483 x 72 120

N = 890 birds Table 27. Observed Occurrence of Previously Marked Aleutian Canada Geese at Crescent City, Spring 1976 before and after Peak Count on 30 March.

Birds Observed Pre-Peak Arrivals Birds Not Observed Banding Status by Total Number before Peak Count Observed after Peak Count until after Peak Count Year and Age Classa Observed No. Percent No. Percent No. Percent

1974 - Adult 14 14 100 11 78.6

1974 - Gosling 17 16 94.1 12 75.0 1 5.9

1975 - Adult 15 15 100 13 86.7

1975 - Gosling 21 21 100 21 100

Total 67 66 98.5 57 86.4 1 1.5 a All birds were banded at Buldir Island. 90 91

This estimate is within 1.1 percent of the population level

based on the direct count. If the Poisson approximation is used, the lower and upper limits of the estimate at 95 percent confidence interval

are 742 and 1068.

Fall 1976. A peak direct count of approximately 1280 was ob­

tained on 12 November when 1250 Aleutians were counted in the Butte

Sink and 29 were recorded at Castle Rock. However, additional birds

were probably in the population as indicated by a 31 October recovery of

a banded bird in the Sacramento-San Joaquin River Delta.

Spring 1977. In a pattern similar to that of the previous year,

the peak spring count of 1150 at Crescent City appeared to represent

most of the population. Of the 148 previously marked birds observed at

Crescent City in spring 1977, 142 (95.9 percent) were seen prior to the

25 March peak, and, of these, 126 (88.7 percent) were observed after the

peak count that spring (Table 28). The 148 birds observed at Crescent

City in spring 1977 represented 85.1 percent of the 174 marked birds

(not including one individual shot on 20 February at Humboldt Bay)

known to have survived to the 23 January end of waterfowl hunting season.

Two individuals were identified through trapping rather than being seen

in band observations. This indicates an unknown number of marked birds

were apparently present at Crescent City but not observed. Also, an

additional 10 marked birds, seen earlier during winter 1976-77 but not

at Crescent City during the spring, were sighted by Yparraguirre (unpubl.

data) in winter 1977-78. These 12 birds not seen in general observations

in spring 1977 comprised 6.9 percent of the marked sample known alive in

spring 1977. Table 28. Observed Occurrence of Previously Marked Aleutian Canada Geese at Crescent City, Spring 1977 - before and after Peak Count on 25 March.

Banding Status by Birds Observed Pre-Peak Arrivals Birds Not Observed Year, Age Class Total Number before Peak Count Observed after peak count until after Peak Count and Location Observed No. Percent No. Percent No. Percent

1974 - Adult 12 11 91.7 8 72.7 1 8.3 Buldir

1974 - Gosling 14 13 92.9 10 76.9 1 7.1 Buldir

1975 - Adult 9 9 100 8 88.9 Buldir

1975 - Gosling 9 9 100 9 100 Buldir

1976 - Adult 25 25 100 23 92.0 Crescent City

1976 - Juvenile 10 8 80.0 7 87.5 2 20.0 Crescent City

1976 - Adult 14 14 100 13 92.9 Buldir

1976 - Gosling 55 53 96.4 48 90.6 2 3.6 Buldir

Total- 148 142 95.9 126 88.7 6 4.1 9 2 93

In addition to the direct counts a spring population estimate based on the Lincoln Index was calculated. Using observations from 6 to

26 March 1977 and the number of birds marked prior to spring 1977 versus the total capture in banding activities in spring 1977 provides an over­ all ratio of 109 marked birds to 640 unmarked birds. Given the 148 marked individuals identified at Crescent City in spring 1977 plus 12 individuals recorded later, a minimum of 160 marked birds was present in the population. The population estimate was calculated as follows:

nM where N is the spring population N m M is the total number of marked individuals n is the total number of birds observed for markers m is the number of marked birds observed

N = 749 x 160 109

N = 1099

The population estimate based on this method is within 4.4 percent of the direct count population level of 1150. The lower and upper limits of the estimate at 95 percent confidence interval based on the Poisson approximation are 908 and 1332. DISCUSSION

Distribution

Fall Migration

Hanson and Smith (1950) and Nelson and Hansen (1959) found that certain populations of Canada geese have clearly defined migratory patterns, moving largely as a unit between specific breeding grounds and wintering areas. The Aleutian Canada geese also follow this pattern to a great degree. Each fall the geese depart the 1990-ha breeding grounds, returning to virtually the same fields on the migration to their wintering area.

Sightings obtained during this study, as well as analysis of earlier records (Byrd and Woolington unpubl. MS.), indicate that

Aleutian Canada geese migrate eastward along the Aleutian Island Chain from Buldir to the western side of Unimak. There is no evidence, at least in recent times, that Aleutian geese use the Izembek Lagoon area along with the Taverner's Canada geese that presently stage there (this study, Johnson et al. 1979). However, based on Murie's (1959) indication that two forms of Canada geese were historically found at Izembek Lagoon, and the fact that the cackling goose migration route lies eastward through the Bristol Bay region at the base of the Alaska Peninsula

(Lincoln 1926, Nelson and Hansen 1959), it is possible that Aleutian

Canada geese used the Izembek Lagoon area in an earlier era prior to their population declines. 95

Several authorities (American Ornithologists' Union 1957, Hansen and Nelson 1964) have made reference to the former presence of migrant or wintering Aleutian geese in British Columbia, Washington and Oregon.

However, Hatler (1973) found no evidence of their presence in British

Columbia. Chapman et al. (1969) recorded two Aleutian geese as part of a 3193-bird sample of Canada geese taken by hunters in the Willamette

Valley, Oregon, during the 1965-66 and 1966-67 waterfowl seasons. How­ ever, P. F. Springer (pers. comm.) examined one of these birds in 1976 and considered it to be a Taverner's Canada goose. Simpson and Jarvis

(1979) recorded no Aleutian geese in a sample of 7150 hunter-bagged

Canada geese taken in the Willamette Valley and at Sauvie Island Wildlife

Management Area, Multnomah County, during the 1976-77 through 1977-78 waterfowl hutning seasons. Based on the findings of these investigators, observations during my study, and the fact that no banded Aleutian geese have been recovered in British Columbia, Washington, or Oregon during the 1974-75 through 1978-79 waterfowl hunting seasons, it seems likely that Aleutian geese rarely make landfall in those areas. The lack of records between the eastern Aleutian Islands and northern California suggests a transoceanic flight. However, southward movement along the coast north of California is possible.

Observations indicate that some Aleutian geese use Castle Rock as an annual fall stopping place. Local observers (Springer 1975) have mentioned the past presence of Canada geese on Castle Rock during fall.

W. Baldwin, a local resident, reported formerly shooting birds matching the appearance of Aleutian geese on the mainland adjacent to Castle Rock during November as early as 1938. 96

Fluctuating viewing conditions prevented a precise determination

of the total number and composition of marked birds in the flock during

falls 1975 and 1976. Thus, it was not known whether the daily counts

represented birds staying in the area or many birds passing through.

However, a large number of geese fly past the Crescent City area in the

fall as indicated by the reports in 1976 and 1977 in Humboldt County and

the Butte Sink.

Although the exact route taken by the geese to the Sacramento

Valley has yet to be verified, evidence points to an inland movement

along the river drainages of the Coastal Range in Del Norte and Humboldt

Counties. Observations reported to me indicate probable Aleutian geese

occur as far south as the Eel River. Earlier observers reported flocks

of up to 225 Canada geese flying east and southeast near Willow Creek,

Humboldt County, and up the Mad and Trinity Rivers, Trinity County, dur­

ing 1973 and 1974 (P. F. Springer pers. comm.). Although the subspecies

was not identified in these sightings, it is likely that any large

flocks of Canada geese in these locations would be Aleutian geese be­

cause the major movements of other subspecies of Canada geese into

California occur over a more inland route to the Klamath Basin (Bellrose

1978). Moffitt (1939) cites "a small but regular (formerly large)

migration of cackling Canada geese down the coast to the vicinity of

Eureka, then inland, up the Trinity and Eel river valleys, probably east

to the Sacramento Valley." Some of these birds could have been

Aleutians, since a specimen collected in Humboldt Bay on 11 January 1914

and referred to by Moffitt as a "lesser Canada goose" has since been identified as an Aleutian goose by P. F. Springer (pers. comm.). 97

Wintering Areas

In a discussion of the wintering ground distribution of Aleutian

Canada geese it should be realized that this study took place during one of California's worst droughts in recorded history (California Dept. of

Water Resources 1977). Craighead and Stockstad (1956) found that en­ vironmental conditions affecting food availability influenced local movements of Canada geese in Montana. It is likely that Aleutian geese would react in a similar manner and spread out if increased forage areas become available in winters of more normal rainfall. However, band return data from 1974-75 and subsequent work by Yparraguirre (1978, 1979) in somewhat wetter years indicate a similar pattern of timing and lo­ cation of use areas as that determined in this study.

Unlike cackling Canada geese, the Aleutian geese were not found to have a wide distribution throughout the Sacramento Valley. The Butte

Sink was determined to be the major use area for the main segment of the population from October to early December, and all evidence indicates it is a traditional annual use area. In addition to the observations dur­ ing this study, Aleutian geese were known to have been present on the

833 Reclamation District during fall 1974 through the band recovery of a bird there on 9 November. Yparraguirre (1978, 1979) has confirmed the continued annual presence of the geese in the same fields in falls 1977 and 1978.

Although the earliest documented presence of Aleutian Canada geese in the Butte Sink ranged from 15 October to 11 November during

1974 to 1977, my interviews with nearby duck club operators and farm workers revealed that some small Canada geese, variously referred to as 98

"cacklers" or "Hutchins' geese", generally arrive in early October, al­

though the exact dates and numbers are not available. The 1977 report

by the West Butte Farms foreman of geese present "since the first of the

October" probably reflects an increased awareness of the birds through

my contacts rather than earlier-than-normal migration.

Observations indicate that almost the entire known population

uses the Butte Sink area during this time. If a September 1976 pre-

migration population estimate of 1300 is assumed (Byrd and Woolington

unpubl. MS.), the 12 November 1976 peak count of 1250 represents 96.2

percent of the population being present in the Butte Sink at that time.

The total percentage of the population using the area could be even

higher if varying amounts of mortality occur during fall migration and

if the 29 geese observed on Castle Rock on 12 November later came to the

Butte Sink. However, an unknown number of birds either bypassed the

Butte Sink or had left prior to my observations as evidenced by the 31

October 1976 band recovery in the Sacramento-San Joaquin River Delta.

During winter 1975-76 the lack of sightings in the Butte Sink after 27 November does not mean that the geese had departed earlier than observed in winter 1976-77. Birds may have been present on the Butte

Creek Farms as observed in winter 1976-77, but during the first winter

I had not conducted surveys there. In winter 1976-77, departure from the area began by at least 22 November based on a band recovery to the south of a bird known to have been present in the Butte Sink earlier in

November.

The timing and location of band recoveries and observations in

Yolo County seem to indicate that at least some geese move southward out of the Butte Sink through the Yolo Bypass area; however, this was not 99 verified by recovery of any banded birds known present at the Butte Sink early in the fall. Surveys of the area indicate the geese do not stop in any numbers but continue south into the Sacramento-San Joaquin River

Delta and the San Joaquin Valley.

Timing of recoveries in the Sacramento-San Joaquin River Delta corresponded with the records from the Yolo Bypass area. This plus the fact that I was unable to locate any groups of Aleutian geese in the

Delta suggests that birds were only moving through this area in a similar pattern to that in the Bypass. In 1976, however, a marked bird not seen earlier in the Butte Sink was shot in the Delta on 31 October.

Grizzly Island is apparently a regular although relatively minor use area. In addition to the documented presence of Aleutian geese dur­ ing my study, California Department of Fish and Game personnel indicated that a small group of geese similar in appearance and habits to the

Aleutian geese had been using the same set of fields "for several years."

Documented arrival on the area ranged from 25 to 27 November for the two winters. In 1975-76 the flock of 20 apparently overwintered at Grizzly

Island State Wildlife Area, whereas in winter 1976-77 the flock departed the area by 15 January, and at least part of the flock were later dis­ covered present in the San Joaquin Valley.

After departure from the Butte Sink area the bulk of the

Aleutian goose population moves into the San Joaquin Valley. In 1977 their presence was documented as early as 25 November in this study.

This pattern of movement and use of localized areas was also indicated by the 1974-75 band returns and has been shown to continue (Yparraguirre

1978, 1979). 100

Use of the Faith Ranch was determined during the winter 1974-75 when a banded bird was recovered on 21 December 1974 on that or the adjacent property. In addition, an unbanded Aleutian goose, identified to subspecies by my 1977 examination of the mounted specimen, was shot from a flock of 15 in January 1975 near Escalon, Stanislaus County, 24 km northeast of the Faith Ranch. Observations were not conducted on the

Faith Ranch during the first year of the study. However, since the presence of large numbers of Canada geese on the ranch is an annual mid­ winter occurrence (J. Rhea pers. comm.), it is highly probable that

Aleutian geese were present in winter 1975-76 and preceding winters.

Band observations and direct counts indicate that a minimum of

80 percent of the known Aleutian Canada goose population was present at the Faith Ranch in January 1977. During this time period, sightings and one recovery occurred as far away from the ranch as 58 km, but it is unknown whether the individuals involved were birds participating in daily movements or birds not associating with the main flock.

Use of the Nemethi Ranch was documented during both winters of the study. The 20 December 1975 recovery from the adjacent Los Banos sewage treatment ponds occurred 1 month earlier in the season than the geese were known present in 1976-77. No surveys of the Nemethi Ranch were made in winter 1975-76. But, evidence that some unknown portion of the flock was using the Nemethi Ranch that year and perhaps earlier is supplied by the ranch foreman's 1977 remembrance that "a flock of small Canadas of about the same size and numbers as these birds have generally been present during January to early March for the last few years." 101

In winter 1976-77, Aleutian geese began moving from the Faith

Ranch southward to the Los Banos area by at least mid January. Subse­ quent band observations indicated that a minimum of 83.1 percent of the birds formerly present at the Faith Ranch utilized the Nemethi Ranch.

However, counts of as many as 1100 Aleutian geese indicated the actual number using the Nemethi Ranch probably encompassed almost the entire population. During both winters Aleutian geese began arriving at Castle

Rock by 10-11 January. Because band observations were not able to be conducted on these initial arrivals, it is unknown whether they came directly from the Faith Ranch, Nemethi Ranch, or elsewhere. Only 5.4 percent of the banded individuals observed at Castle Rock during March and April 1977 had not been observed at the Nemethi Ranch during January to March.

The extent of Aleutian Canada goose presence in the southern

California-Arizona-northern Mexico area is uncertain. Evidence in­ dicates that actual usage of this region during the study was minimal.

Although the five birds shot represent 41.7 percent of the total band recoveries for winter 1975-76, the importance of this percentage appears inflated when one considers that four of the birds were from one family and that the main population was probably in areas closed to Canada goose hunting. The Arizona recovery came from an area that receives very little use by intermediate-sized Canada geese (R. Delaney pers. comm. to P. F. Springer). The presence of. Aleutian geese at Salton Sea

National Wildlife Refuge again in winter 1977-78 indicates that the birds may move into the area on a regular basis. But, given the excel­ lent viewing conditions at the refuge (M. R. McLandress pers. comm.) and the fact that no other sightings have been reported there, it appears 102 unlikely that any substantial number of Aleutian geese frequent the

Salton Sea area.

Overall, the band sightings and recoveries from winters 1974-75 through 1976-77 show that the bulk of the Aleutian goose population frequents the same areas each year (Fig. 12). The geese move inland from the northern California coast to the Butte Sink area of the

Sacramento Valley during October and November. By mid-November to early

December they shift southward. A small number move into the Sacramento-

San Joaquin River Delta and Suisun Marsh region, but most birds go to the San Joaquin Valley where they frequent the Modesto and Los Banos areas. A few birds then return northward to the coast, but most birds remain in the Central Valley until mid February to early March before moving to the Crescent City area.

Spring Migration

Because few concrete records exist between the San Joaquin

Valley and the northern California coast, the route taken from the wintering areas is speculative. Some of the geese apparently return via the Butte Sink area in February and March, probably moving over the

Coast Range in the same pathways they took during the fall. However, given the observed northwest flight path and known flight time of less than 13 hours (minimum possible average flight speed: 47 km/hr) to

Crescent City for one individual, a more direct flight for geese from the Los Banos area is indicated, perhaps to the coast via the Sacramento-

San Joaquin River Delta, and then northward. Records between 19 February and 4 March 1978 indicate that a portion of the flock reaches the coast at some point south of Humboldt Bay and then flies northward to Crescent

City. 103

Figure 12 Wintering Range of Aleutian Canada Geese. 104

Dates of initial arrival to the spring staging area at Crescent

City were similar in both springs of the study, with first noted arrivals on 10 January in 1976 and 11 January in 1977. The build-up in numbers of geese appeared earlier in spring 1977. Less than 50 percent of the population was present until 8 March in 1976, whereas in 1977 that percentage was present by 24 February. The peak count on 30 March-11

April 1976 and 25 March 1977 both were earlier than the 14 April peak count obtained in 1975 (Springer 1975). However, fewer counts were taken in 1975. It is possible that drought conditions during the study may have caused an earlier build-up at Crescent City than noted in 1975.

Springer estimated that the 1975 counts of Aleutian geese as they flew from Castle Rock to the mainland were within 5 percent of the actual number present. Counts made concurrently with Springer in 1976 and 1977 indicated my accuracy level was similar.

Many authors have noted the impact of environmental conditions on migrational movement of waterfowl (Bagg 1950, Hochbaum 1955,

Miskimen 1955, Bellrose 1957). Springer (1975) found that northward departure of Aleutian Canada geese from Crescent City in spring 1975 coincided with a cold weather front and southerly winds, with the birds apparently using the tailwinds to aid migration. I also found this to be true in 1976 and 1977. Although departures of geese from 12-20 April

1976 occurred during both northerly and southerly winds, major movement of the birds occurred on 21, 23, and 28 April, days of south-southeast winds (avg. 148°-162°) with surface velocities up to 19 km/hr. The 20-

22 April exodus of Aleutian geese in 1977 occurred during a period of o o southwest winds (180 -220 ) with surface velocities ranging from 8 to

32 km/hr. 105

Observations of geese departing Crescent City indicates the

initial spring migration path lays offshore parallel to the coastline

of northern California. At what point between there and Alaska the

geese angle westward away from the coastline is not known. The lack of

verified or positive sightings of Aleutian Canada geese in Oregon,

Washington, or British Columbia indicates that no significant number of

Aleutians make landfall in those areas. Although a flock of 70 report­

edly stopped at Sand Island, Oregon, at the mouth of the Columbia River

in spring 1975, subsequent searches have failed to obtain any substan­

tiating records.

Unlike fall migration there are no records of the geese in the eastern Aleutian Islands during April and May. This is probably attributable to a lack of observers rather than the geese not migrating through the area. The available sightings indicate the geese migrate westward along the island chain from at least the central Aleutian islands, arriving at Buldir by early May. King (Kenyon and King 1965) found geese on Buldir on a 5 May 1965 aerial survey. Byrd and

Woolington (unpubl. MS.) reported that birds were observed on Buldir on

9 May 1974 and that most of the breeders and subadults were present by mid-May. However, late May to mid-June records and sightings on

Amchitka and the Pribilof Islands indicate that some of the yearlings, subadults, and perhaps non-breeding adults arrive at Buldir later, if at all, or may engage in molt migrations as described by Salomonsen

(1968) and Bellrose (1976). 106

Ecology on Main Use Areas

Localized Use Patterns

Observations allowed only general conclusions on habits and use patterns. Like other geese, Aleutians select flooded or marshy roost sites which provide protection from mammalian predators. The only exception to this type of roost, Castle Rock, provided even more security than nearby lakes. In most known use areas, Aleutian geese did not follow the usual daily activity pattern of Canada geese of flying to a feeding area in the morning, returning to the roost site at mid-day to preen and loaf, and then flying back to the feeding area for a late afternoon feeding season. Instead, at the Butte Sink, Los Banos, and

Crescent City areas they typically fly from the nightly roost and remain in the feeding area all day. At the Faith Ranch, those birds engaging in morning flights off the property, fed in the pasture upon their return later in the morning rather than seeking the roost site. The only instance of a mid-day return to the roost site occurred at Grizzly

Island in 1976-77. This behavioral pattern was probably due to a lack of water in the feeding area.

Subjective observations indicated that feeding was most intensive during morning and late afternoon, especially at the Butte Sink, but a high level of, feeding occurred throughout the day at all the use areas.

Raveling (1979) found that cackling geese grazing exclusively in pasture during winter needed 8-9 hours of feeding to meet their energy require­ ments. On the same type of diet, Aleutian geese apparently require a similar length of time for feeding. In spring the need for food intake would increase. The importance of fat reserves for spring migration 107 and nesting has been discussed by Barry (1962), Hanson (1962), Raveling

(1978), and others. The increasingly longer daytime periods spent on the mainland at Crescent City in March to April are probably in response to the need for energy storage and depleted forage on Castle

Rock.

Food Items

Observations during the study revealed that Aleutian Canada geese exhibit similar food preferences to those described by Olgilvie

(1978) for small Branta-type geese. Grazing, whether on introduced grasses and clover in irrigated fields, cultivated green crops, or natural grasses was the predominant feeding strategy utilized for most of the wintering period. However, like other small geese, the Aleutians were able to switch to other food items. In the Butte Sink, where no pastureland was present, the geese fed almost exclusively by gleaning waste crops. Evidently Aleutian geese prefer beans over rice because usage of the adjacent rice fields in fall 1976 did not occur until the birds had been present in the area at least 21 days.

Interviews of hunters recovering marked Aleutians indicate that some of the geese in the Sacramento-San Joaquin River Delta also feed in harvested fields of corn.

Relation to Other Wildlife

Observations during the study showed the Aleutian geese form virtually monospecific flocks at initial fall arrival in the Butte

Sink and again at the Crescent City spring staging area. The mixed species assemblages observed later in the Butte Sink and at Los Banos 108 appear to be the result of other geese moving into those areas where

Aleutian geese had established a daily use pattern. It was not deter­ mined in this study whether other geese are present at the Faith Ranch prior to the annual arrival of Aleutians. In all these areas the different species were intermingled into one to several large mixed flocks. Although no quantified data are available, general observations revealed that Aleutians form small groups throughout the large flocks.

This would indicate the Aleutian goose population is composed of the typical Canada goose flock aggregation of subflocks and family units as described for Interior Canada geese by Raveling (1969).

In all the main use areas the presence of large birds in flight over the flock usually caused the Aleutian geese to flush. Since bald eagles are virtually the only predator of adults and of fledged young on

Buldir during the summer, such a reaction is probably a behavioral trait that stems from the breeding grounds.

Relation to Human Activity

Each year Aleutian geese switch from a breeding ground where human impact is negligible to wintering areas having some of the most intensive agricultural operations and hunting pressure in North America.

As noted for other Canada geese (Palmer 1976), Aleutians have been able to adapt to habitat changes on the wintering range by feeding in pastures and on cultivated crops. Curtailment of legal shooting by the establish­ ment of Canada goose hunting closures has done much to reduce human impact through hunting on this subspecies. The constant monitoring by study and enforcement personnel further limited human harassment on major concentration areas. However, even before enactment of these 109 closures the main flock was evidently using areas of restricted human access and hunting pressure.

Williams (1967) discussed how easily Canada geese lose their fear of man. Aleutian geese exhibited this trait as they became in­ creasingly more tolerant of my study vehicle, as well as the vehicles driven by ranch workers, on the main use areas. Hanson and Smith (1950) and others have described the dangers of such conditioning to Canada geese populations. However, despite my presence, Aleutian geese appeared to retain a more normal level of wariness during the hunting seasons.

They would not allow close approach by humans on foot, or by unfamiliar vehicles. It is possible that with continued protection and monitoring the geese would, in time, become more trusting and thus more vulnerable when they leave the protected areas.

In contrast to the intolerance exhibited toward large birds in flight over the flock, the geese were amazingly indifferent to the presence of low-flying fixed-wing aircraft. This acceptance over most of the wintering range probably indicates a learned behavior, possibly from daily association with airplanes at the Crescent City staging area.

Population

Mortality Factors

Recoveries of banded and unbanded birds during both years of the study indicate that hunting constitutes the major mortality factor for

Aleutian Canada geese on the wintering grounds. If documented mortality is adjusted to exclude trapping fatalities, hunter kill accounted for

87.0 percent of the recorded loss in 1975-76 and 70.4 percent in winter

1976-77. Although the study introduced some biases in recoveries, such 110 data give a good indication of the timing and geographic location of much of the loss. Movement affected the amount of hunting mortality.

Over one-third of the documented loss due to hunting occurred from 20

November to 15 December when the geese evidently shifted from the Butte

Sink to the San Joaquin Valley via the Yolo Bypass and Sacramento-San

Joaquin River Delta. Aleutian geese ranging off the Faith Ranch in

1976-77 were recovered by hunters at a greater rate than when the birds were staying within a restricted area at the Butte Sink earlier that winter. Koerner et al. (1974) also found a relationship between amount of movement and vulnerability to hunting in Canada geese in Ohio.

Illegal kill both inside areas closed to Canada goose hunting and after the general waterfowl season was recorded for a minimum of six birds. This constituted 15.4 percent of the documented hunting mortality. Actual illegal kill was undoubtedly higher than documented.

Illegal spring shooting at Crescent City appears to have been a chronic condition, at least before the study. Several local residents were aware of instances of poaching during March and April in years prior to

1976. One individual knew of at least six birds being taken by a single party in spring 1975. This practice has been greatly reduced by the presence of project personnel during and after my study.

Loss to disease may be greater than documented due to the large number of unidentified small Canada goose wings found in the winter

1976-77 fowl cholera outbreak at the Faith Ranch and the fact that the site was not monitored during the first year of the study. Although no losses from disease were recorded at Crescent City, avian cholera has occurred on the Bliss Ranch (Oddo et al. 1978), and future outbreaks pose a potential risk to Aleutian geese during spring staging. 111

Other studies (Durant 1956, Jarvis 1975) have documented losses

from impaction after dry soybeans ingested by Canada geese swelled in

the birds' gullets. Although no such mortality was observed in the

Butte Sink, gullet impaction from dry beans could pose a potential risk

before the fields are flooded.

Mortality Rates and Survival

Band recoveries have been used by many researchers to calculate estimates of annual mortality of waterfowl populations (Chapman et al.

1969, Grieb 1970). These dynamic and time-specific recovery rate meth­ ods (Geis and Taber 1963) require a rather large number of recoveries to be accurate and, in the case of the former, require band recoveries over the entire life span of the animal being studied. Given the small num­ ber of direct hunter recoveries and the duration of this study, such approaches are not appropriate in assessing mortality rates in the

Aleutian Canada goose population at this time. In addition, the pres­ ence of auxillary bands and the characteristics of the Aleutian goose study would introduce extreme biases into a standard assessment of mortality. Bellrose (1955), Geis and Atwood (1961), and others have discussed the different factors affecting band return rates. Martinson and McCann (1966) calculated a 36.1 percent reporting rate from 1962 to

1965 for recoveries of Pacific Flyway geese with standard U. S. Fish and

Wildlife Service bnads, but concluded such a rate might not be correct for other time periods or conditions.

At the onset of the study, Aleutian geese shifted from an un­ monitored flock subject to normal hunting pressure to a population having hunting closures over much of its wintering range, increasingly more 112 intense monitoring and protection by study and law enforcement personnel, and high project publicity. The resultant, unquantified variables ar­ rived at both subjectively and through hunter interviews include:

1. Differential reporting rates between birds recovered in

areas open to Canada goose hunting and the Canada goose

hunting closure zones.

2. Failure of hunters to report recoveries in areas open to

Canada goose hunting because of fear of being cited under

the Endangered Species Act.

3. Failure of hunters to report recoveries because of fear of

having Canada goose hunting closures extended in time or

area.

4. Failure of hunters to report recoveries because of anger

over establishment of Canada goose hunting closures.

5. Increased reporting of recoveries due to hunter curiousity

over birds having auxiliary markers.

6. Increased reporting rate of recoveries by hunters who had

become aware of the project. This is reflected by the fact

that 27.3 and 41.7 percent of the hunting mortality band

recoveries in winters 1975-76 and 1976-77, respectively,

were from hunters reporting their recoveries directly to

local wildlife agency personnel.

7. Changes over time of awareness by hunter check station

personnel of the significance of banded Aleutian geese. 113

8. Differences in probability of recovering bands from, all

sources of mortality because of differential monitoring of

major flock use areas during 1975-76 and 1976-77.

9. Unknown significance of leg marker loss by birds.

Because of the unknown impact of these factors and the low

number of recoveries, it is felt that observations of banded geese,

although a measure of minimum survival only, describe the mortality and

survival rates of the birds more accurately than direct band recoveries.

If it is assumed that all marked individuals not subsequently observed

were dead, Aleutian geese had a lower maximum wintering ground mortality

rate than the annual mortality rate reported for other races of small

Canada geese which are subjected to normal hunting pressure (Table 29).

Although the wintering ground mortality does not encompass all the loss

incurred during a year, most of the annual mortality for Canada geese is

a result of hunting mortality (Palmer 1976). Natural annual mortality

rate estimates reported for geese (Class II to adults) range from 5.6

percent for dusky Canada geese (Henny 1967) to 9.4 percent for snow

geese (Rienecker 1965). Observations of Aleutian Canada geese from

Buldir and cackling Canada from the Yukon-Kuskokwim Delta (Mickelson

1975) indicate that most of the natural mortality for adults occurs away from the breeding grounds. Since hunting mortality composes most of the annual loss, and most of the adult natural mortality apparently occurs during winter, the calculated wintering mortality rate may com­ prise the majority of the annual mortality rate for Aleutian geese past the age of fledging. However, since this population receives protection from hunting some unknown level of compensatory mortality, including that on the breeding grounds, may be occurring. This would increase the Table 29. Comparison of Maximum Winter Mortality Rates of Aleutian Canada Geese with Annual Mortality Rates of Other Races of Small Canada Geese.

_ Mortality Rate Mortality Rate of Adultsa of Juveniles Race Time Period (Percent) (Percent) Source

B. c. leucopareia Winter 1975-76 12.1 51.2 This study c c B. c. leucopareia Winter 1976-77 13.6-16.9 25.0-35.4 This study

B. c. minima 1949-1954 31.9 46.0 Nelson and Hansen (1959)

B. c. hutchinsii 1951-1966 32.0 51.0 Grieb (1970)

B. c. taverneri 1948-1958 25.4 45.6 Timm (1974) aWinter mortality rate for leucopareia; annual mortality rate for other subspecies for period indicated. b Winter mortality rate for leucopareia; annual mortality rate for other subspecies for first year after banding. c The first listed percentage i calculated from the number of banded birds known alive before and after the waterfowl season and based on the assumption that all were still alive in April 1977 but not necessarily seen at Crescent City. The second listed percentage is based on only birds seen at Crescent City. 11 4 115

importance of losses on the breeding grounds in calculating annual

mortality. Continued observations of marked geese in future studies

would make direct determination of total annual mortality rates possible.

If it is assumed that band reporting rates are equal for all age

groups, juvenile Aleutian geese were 17 percent more vulnerable than

adults to hunting. Comparing this with the range of maximum winter

mortality rates of 12.1-16.9 percent for adults and 25.0-51.2 percent

for juveniles (Table 28) indicates that birds in their first winter are

more susceptable than adults to non-hunting mortality also.

Given the September 1976 premigration estimate of 1300 birds

(Byrd and Woolington unpubl. MS.) and the April 1977 spring population

count of 1150, a loss of approximately 150 birds (11.5 percent) occurred

during winter 1976-77. The September 1976 estimate included a population

structure of 274 breeding birds (21.1 percent), 516 non breeders (39.7

percent), and 510 goslings (39.2 percent). Overall minimum survival of

this population based on observations of banded individuals was found to

be 12.7 percent lower than survival based on fall and spring counts if

calculated to April 1977, and 6.6 percent lower if calculated for known

survival only to the end of waterfowl hunting season on 23 January 1977

(Table 30). The difference between documented survival of banded birds

at the end of the 1976-77 waterfowl season and April 1977 indicates that over 90 percent of the birds surviving the waterfowl season were alive in April. Sample variation may account for the 6.6 percent difference between documented survival of the banded birds at the end of the waterfowl season and survival of the flock based on population counts. Table 30. Comparison of Estimated Winter 1976-77 Mortality Based on Population Counts and on Sightings of Banded girds.

Winter Mortality Winter Mortality Winter Mortality No. Geese Based on Population Based on Sightings Based on Sightings in Population Counts, Sept. of Banded Birds, a of Banded Birds, Age Class Sept. 1976 1976-April 1977 Sept. 1976-Jan. 1977 Sept. 1976-April 1977a

Adult 790 Unknown 107 134

Gosling 510 Unknown 128 181

Total 1300 150 (11.5%) 235 (18.1%) 315 (24.2%) a Maximum mortality rates from Table 28. 116

117

Population Levels

Craighead and Stockstad (1956) found they could accurately

determine the population levels of a small population of 3000 to 3300

Canada geese in Montana through direct censusing. During this study,

direct counting methods on a population approximately one-third the size

of and more restricted in use area than the Montana flock was also

found to be highly accurate. Daily counts of small groups of Aleutian

geese flying from the roost site to the mainland provided an accurate

assessment of the birds present at the Crescent City spring staging

grounds. Band observations and recoveries both during and after my study indicated that the peak counts there in 1976 and 1977 represented

almost the entire known population. Further evidence that these counts

comprised the entire population is provided by the population figures

calculated by the Lincoln Index which are only 1.1 and 4.4 percent lower than the direct counts in springs 1976 and 1977.

Data collected during this study and on the breeding grounds facilitated determination of fall and spring populations during the study period. Since known winter mortality was not significantly dif­ ferent during the two seasons (Tables 22-24) and production rates on the breeding grounds were similar from 1974 through 1976, (Byrd and

Woolington unpubl. MS.), the 11.5 percent winter mortality rate for

1976-77 can be applied to the spring 1976 count of 900 to calculate an estimated fall 1975 population of 1020. 118

Pre-Hunting Closure Population Level

If it is assumed that the arrival and departure patterns observed at Crescent City in springs 1976 and 1977 indicate the pattern of spring staging prior to the study, the peak count of 790 (Byrd and Springer

1976) represented the total spring population in April 1975. If the

Buldir birds were at a stable population level where recruitment: equaled mortality, the 1974 fall population would have been approximately the same level as in fall 1975 (1020). Reduction of the population in the spring to the recorded 790 would give a mixed population of adult and immature Aleutian geese a 1974-75 winter mortality rate of 22.5 percent.

Such a mortality rate, which is believed to represent the large majority of the population loss through a year, is lower than the recorded annual mortality rates for cackling and Taverners' Canada geese (Table 28).

If the Buldir flock was at a stable level the fall and spring numbers of Aleutian geese for 1974-75 can be concluded as approximate yearly population levels at least for recent years. Neither Murie (1959) nor Jones (1963) found any indication of a population higher than determined for 1974-75. However, population declines since the early

1960's for cackling geese and white-fronted geese wintering in California have been determined (Timm and Dau 1979, O'Neil 1979). It is possible that Aleutian geese may have experienced the same type of decline dur­ ing that time period.

Population Increases

Population levels of Aleutian geese made dramatic increases during the study. The spring population was 13.9 percent higher in 1976 119 than in 1975, and was 27.8 percent higher in 1977 than in 1976. The overall increase from spring 1975 to spring 1977 was 45.6 percent.

These changes in population appear to be a direct result of the Canada goose hunting closures initiated in winter 1975-76 which reduced winter mortality from a calculated 22.5 percent to 11.5 percent. Under these circumstances, the population would be expected to increase until new limiting factors on either the breeding or wintering grounds are encountered. CONCLUSION AND RECOMMENDATIONS

It was found that Aleutian Canada geese are very traditional in

their selection of wintering use areas in California. They return to

virtually, the same fields each year. Most of the population remains together as one flock that shifts to different locations within the state throughout their stay. Some of the birds in the fall stop at Crescent

City for a while, but most fly directly to the Butte Sink of the

Sacramento Valley. Thereafter they move through the Sacramento-San

Joaquin River Delta in the winter to the upper San Joaquin Valley. By spring virtually the entire known population gathers together at the

Crescent City staging grounds prior to the return to Buldir. Although

Aleutian geese do use harvested croplands, most of the major use areas are pastureland where the birds subsist almost entirely by grazing.

Because of the endangered status of Aleutian Canada geese and the urgency to protect those birds vulnerable to hunting, management actions were implemented as field data were being collected rather than waiting until completion of field work and presentation of final recommendations. Following the 21 November 1975 discovery of Aleutian geese in the Butte Sink, the Sacramento Valley Canada goose hunting closure was enlarged on 26 November to encompass that area. This closure with additional boundary modification in 1976 has continued to remain in effect. As a result of data collected on movement between the

Sacramento and San Joaquin Valleys in winters 1975-76 and 1976-77, modifications in timing of the Canada goose hunting closures were en­ acted in summer 1977. The Sacramento Valley closure was continued from 121 the 22 October beginning of the waterfowl hunting season until 15

December, but the starting date of the San Joaquin Valley closure was moved up from 15 December to 25 November. In addition, because no evidence of the presence of Aleutian Canada geese was obtained in

Mendocino County since the discovery of a dead, captive-reared bird in winter 1974-75, that area was excluded from the northwestern counties closure zone in winter 1977-78.

The 45.6 percent population increase from 790 in spring 1975 to

1150 in spring 1977 is apparently directly attributable to the protec­ tion afforded by the Canada goose hunting closures which began in winter

1975-76. Maintenance of these closures, and modification if movement patterns change, are necessary to allow maximum survival of the wild population and of geese released in future reintroduction efforts.

Protection of the main use areas is as, or even more, important to the restoration efforts as reduction of direct hunting mortality. As a result of this study and the previous investigation by Springer (1975) the use area surrounding Point Saint George at Crescent City was pro­ posed for listing as critical habitat by the U. S. Fish and Wildlife

Service in 1977. Plans were advanced to include Castle Rock as part of the National Wildlife Refuge system and to lease the pastures of the

Reservation Ranch. In September 1979, Castle Rock was purchased by the

Nature Conservancy. Also in that year the Bliss Ranch was purchased by the State of California as part of a 2120-ha acquisition of Lake Talawa and lands west of Lake Earl. Tentative plans at time of this writing are for Castle Rock to be managed in the future by the U. S. Fish and

Wildlife Service, the ocean beach of the former Bliss Ranch to be managed by the California Department of Parks and Recreation, and the 122

mainland pasture to be managed by the California Department of Fish and

Game (P. F. Springer pers. comm.).

Despite the protection given these areas by acquisition it is

urged that efforts be accelerated to further protect the Crescent City

staging grounds through critical habitat designation. Management plans

initiated at the Bliss Ranch by the California Department of Fish and

Game should be aimed at enhancing the Aleutian Canada goose population

status and retaining the present condition of the pasturelands. Be­

cause of the risk of mortality due to avian cholera outbreaks at Lake

Talawa, plans to lease Reservation Ranch, if necessary to maintain the

property as a grazed pastureland and retain the goose levels of springs

1976 and 1977, should be continued.

The Aleutian Canada goose use areas in the Butte Sink, near

Modesto, and near Los Banos should also be proposed for critical habitat

designation. Because of current land-use practices in these areas,

management objectives can be fulfilled by cooperation with local land­

owners, easements, and monitoring by agency personnel rather than by

acquisition. An easement program to preserve waterfowl habitat in the

Butte Sink and the Los Banos area was initiated by the U. S. Fish and

Wildlife Service in 1979.

Protection of both the geese and of the integrity of the major

use areas is necessary to insure maintenance and improvement of current population levels. Attemps to reestablish breeding geese on former nesting islands in the Aleutians should increase the population even more and permit future relaxation in the present closure regulations.

Until that time, current protection measures are and will be important 123 components of the recovery plan to upgrade the Aleutian Canada goose from endangered species status. REFERENCES CITED

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APPENDIX A. Common and Scientific Names of Avian Species from American Ornithologists' Union (1957) and Bellrose (1978).

American green winged teal Anas crecca carolinensis

American wigeon anas americana

Bald eagle Haliaeetus leucocephalus

Black brant Branta bernicla nigricans

Canada goose Branta canadensis

Aleutian B. c. leucopareia

Cackling B. c. minima

Dusky B. c. occidentalis

Great Basin B. c. moffitti

Interior B. c. interior

Richardson's B. c. hutchinsii

Taverner's B. c. taverneri

Common raven Corvus corvax

Great blue heron Ardea herodias

Lesser snow goose Anser c. caerulescens

Mallard Anas g. platyrhynchos

Marsh hawk Circus cyaneus

Northern shoveler Anas clypeata

Peregrine falcon Falco peregrinus

Pintail Anas a. acuta

Red-tailed hawk Buteo jamaicensis

Ross' goose Anser rossii

Turkey vulture Carthartes aura

Western gull Larus occidentalis

Whistling swan Cygnus columbianus 132

APPENDIX A. Common and Scientific Names of Avian Species from American Ornithologists' Union (1957) and Bellrose (1978). (continued)•

White-fronted goose Anser albifrons frontalis

Wood duck Aix sponsa 133

133NDIX B. Common and Scientific Names of Plant Species from Munz (1959), Mason (1957), and Usher (1974).

Beach strawberry Fragaria chiloensis

Bermuda grass Cynodon Dactylon

Birds-foot trefoil Lotus corniculatus

Black-eyed bean Vigna catjang

Bulrushes Scirpus spp.

Bush lupine Lupinus arboreus

Bur-clover Medicago hispida

California bay Umbellularis california

Cat's ear Hypochoeris radicata

Cattails Typha spp.

Cinquefoil Potentilla Egedei

Common barley Hordeum vulgare

Common dandelion Taraxacum officinale

Common rush Juncus effusus

Cotton Gossypium sp.

Corn Zea mays

Curly dock Rumex crispus

Dallis grass Paspalum dilatatum

Duckweeds Lemna spp.

Fescues Festuca spp.

Fremont cottonwood Populus Fremontii

Gum plant Grindelia stricta

Iris Iris Douglasiana

Kentucky bluegrass Poa pratensis

Knotweed Polygonum Paronychia 134

APPENDIX B. Common and Scientific Names of Plant Species from Munz (1959), Mason (1957), and Usher (1974) (continued).

Lima bean Phaseolus lunatus

Lupine Lupinus littoralis

Mediterranean barley Hordeum Hystrix

Mustard Brassica sp.

Plantain Plantago sp.

Red alder Alnus oregona.

Red clover Trifolium pratense

Red fescue Festuca rubra

Red-stemmed fillaree Erodium cicutarium

Redtop Agrostis alba

Reed grass Calamagrostis nutkaensis

Rice Oryza sativa

Rushes Juncus spp.

Ryegrass Lolium sp.

Safflower. Carthamus tinctorius

Salmon berry Rubus spectabilis

Salt rush Juncus Lesueurii

Sedges Carex spp.

Sitka spruce Picea sitchensis

Shepard's purse Capsella Bursa-pastoris

Slough sedge Carex obnupta

Smartweeds Polygonum spp.

Sorghum Sorghum vulgare

Spikerushes Eleocharis spp.

Spiraea Spiraea Douglasii 135

APPENDIX B. Common and Scientific Names of Plant Species from Munz (1959), Mason (1957), and Usher (1974) (continued).

Sugar beet Beta vulgaris

Twinberry Lonicera involucrata

Tomato Lycopersicon lycopersicon

Valley oak Quercus lobata

Velvet grass Holcus lanatus

Wild buckwheat Eriogonum latifolium

Willows Salix spp.

White clover Trifolium repens