Fall food preferences of blue grouse in the White Mountains of Arizona
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Authors LeCount, Al
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Link to Item http://hdl.handle.net/10150/554060 FALL FOOD PREFERENCES OF BLUE GROUSE
IN THE WHITE MOUNTAINS OF ARIZONA
by
Albert L. LeCount
A Thesis Submitted to the Faculty of the
. DEPARTMENT OF BIOLOGICAL SCIENCES
In Partial Fulfillment of the Requirements For the Degree of
MASTER OF SCIENCE WITH A MAJOR IN WILDLIFE BIOLOGY
In the Graduate College
THE UNIVERSITY OF ARIZONA
19 7 0 STATEMENT CY AUTHOR
This thesis has been submitted in partial fulfillm ent of re quirements fo r an advanced degree at The U niversity of Arizona and is deposited in the University Library to be made available to borrowers under rules o f the Library.
Brief quotations from this thesis are allowable without special permission, provided that accurate acknowledgment o f source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the Graduate College when in his judg ment the proposed use of the m aterial is in the inte rests of scholar ship. In a ll other instances, however, permission must be obtained from the author.
SIGNED:
APPROVAL BY THESIS DIRECTOR
This thesis has been approved on the date shown below:
^ r xL j , tf-X i ' ? o 1 \Lyle K. Sowls Date ProfessoVNof Biological Sciences ACKNOWLEDGMENTS
I wish to thank Dr. L. K. Sowls, Leader of the Arizona Coopera tive W ildlife Research Unit, for his assistance throughout the study and during preparation of this thesis. Also, appreciation is expressed to Dr. C. R. Hungerford for his advice and help, and to Dr. N. S. Smith for his editing suggestions.
I also wish to thank my supervisor Mr. Robert White, Arizona
Game and Fish Department, who permitted me to work on this study along with my duties of W ildlife Manager. My sincerest thanks is also given to all the personnel of Region 1, Arizona Game and Fish Department, who spent many hours both on horseback and on foot collecting material which was essential for this study.
Appreciation is also expressed to R. Baker and E. Buckner, United
States Forest Service, for their assistance in the field study.
I especially wish to thank my wife, Karen, for her advice, en-
couragment, and for her tireless assistance in the field. TABLE OF CONTENTS
Page
LIST OF ILLUSTRATIONS...... v
LIST OF TABLES...... v1
ABSTRACT...... v i i
1. INTRODUCTION......
H isto ry ...... 1 Purpose ...... CM CO Geology, Climate, and Vegetation
2. METHODS...... 7
3. RESULTS AND DISCUSSION...... 10
Food A vailab ility ...... 10 Plant Foods Eaten by Blue Grouse ...... 13 Animal Foods Eaten by Blue Grouse ...... 24 G r it ...... 24 W a t e r ...... 25 Crop V o lu m e ...... 25 D ifferences in D iets o f Adults ...... 26 Differences in Diets Between Adults and Juveniles. . 30 Differences in Diets Between Areas...... 36 Differences in Diets Between Arizona Grouse and Northern Grouse...... 38
4 . CONCLUSION ...... 41
LITERATURE C IT E D ...... 43
iv LIST OF ILLUSTRATIONS
Figure Page
1. The White Mountain study area in east central Arizona ...... 4
2. Typical Arizona blue grouse habitat on E s cu d illa Mountain ...... 6
3. Typical vegetative height selected by blue grouse hens w ith broods...... 29
4. A comparison of the major plant and animal foods eaten by 31 adult and 51 juvenile blue grouse...... 32
5. A comparison of foods eaten by blue grouse on Escudilla and Green's Peak in September, 1969 ...... • • 37
v LIST OF TABLES
Table Page
1. Plant and animal matter available to Arizona blue grouse in September as revealed by exam ination o f two 100 foot vegetation transects on Green's P e a k ...... 11
2. Relative importance of food items found in crops from 99 Arizona blue grouse taken in September. . .15
3. A comparison of the five major food items eaten by blue grouse in north central Washington and the White Mountains of A r i z o n a ...... 39
v i ABSTRACT
This study was conducted in the White Mountains of Arizona between 1966 and 1969 to determine the fa ll food preferences of blue grouse (Dendragapus obscurus). Vegetational analysis showed that an abundance of food species were available in the fa ll. Examination of
99 grouse crops showed that 18 plant species and six families of in vertebrates were taken. Food of five major categories made up 94 per cent of the total diet, and were considered to be preferred. These categories were: Wild pea and vetch (Lathyrus arizonicus and Vicia americana) , raspberry (Rubus s trig o s u s ) , aspen ( Populus tre m u lo id e s ), dandelion (Taraxacum sp.), and Douglas fir (Pseudotsuga menziesii).
Differences existed between the diets of adult male and female blue grouse because sexes were separated. Females spent much of their
time in the open meadow areas, while males remained in the timber.
Diets of juvenile grouse were similar to the diets of adults except
a greater amount of animal matter was taken. Blue grouse diets also
varied between areas because of differences in the availability of
specific food items. Blue grouse in Arizona appear to have an ade
quate diet in the fall because a good selection of highly preferred
food species is available.
vii CHAPTER 1
INTRODUCTION
H is to ry
Blue grouse (Dendragapus obscurus) are found from southeast
Alaska to east central Arizona. Several subspecies are found through
out this range. The one occurring in Arizona is the blue, or dusky
grouse, (Dendragapus obscurus obscurus), (P hillips, Marshall, and
Monson 1964).
The firs t records of blue grouse in Arizona were made by
Mearns and Merriam on their expeditions to Arizona in the late 1880's.
Mearns (1890) found grouse abundant in the White Mountains. He thought
they should also be found in the San Francisco Peaks near Flagstaff,
but a search by his party failed to find any. Merriam (1890) did not
observe grouse on the San Francisco Peaks but a camp visitor did. This
visitor was Mr. John Swinburne of St. Johns, Arizona. Merriam believed
that Mr. Swinburne was fam iliar with the species in the White Mountains
and had no doubt about the correctness of the identification.
Blue grouse were firs t mentioned elsewhere in Arizona in the
1930's. Grater (1937) reported that blue grouse were common residents
o f the north rim o f the Grand Canyon. B ailey (1939) found them gener
ally distributed and fa irly common on the Kaibab Plateau. Somewhere
between 1939 and the 1950's a change in the status of grouse occurred
in the Grand Canyon area. Pettingi11 (1953) reported that blue grouse
1 2 were a rarity bn the north rim by 1950. The reasons for this decline are obscure because of inadequate records.
In the 1930's a report was also made of blue grouse in the
Chuska Mountains of Arizona. Phillips (1937) reported that he observed a pair of birds at an elevation of approximately 8,800 feet. He indi cated that these birds were not numerous in the Chuskas. He did state, however, that the Navajo Indians, who inhabited this area, did not hunt grouse. This would indicate that the low population was not caused by hunting.
Today blue grouse are found in all of the areas described in
the early reports except the San Francisco Peaks where the last birds were observed in 1910 (Phillips, Marshall, and Monson 1964). Their
status in various areas has remained about the same as it was in the
1890's with the exception of the Kaibab Plateau. In this area a pop
ulation decline occurred sometime after 1939. It appears from these
records that blue grouse have never been widespread in Arizona.
In 1964 Arizona held its firs t blue grouse hunt of two days.
In 1965 the season was extended to four days, where it remained through
1969. Each year participation and interest in blue grouse hunting has
increased. This increase in interest has brought about the need for
knowledge of food preferences and habitat requirements of this species
in order to assure it s sound management.
Purpose
A review of the blue grouse literature shows that grouse studies
have been conducted in n ea rly a ll parts o f it s range. Many o f these 3
studies have been to determine food habits. Beer (1943), Dragness
(1968), Boag (1963), and Bauer (1962) determined food preferences of
blue grouse in Washington. Boag (1958), worked on this problem in
Canada, and Mussehl (1960) examined it in Montana. Beer (1943)
studied food preferences in Idaho, Belding (1892) did some work on
grouse in California, and Flint (1928) did a limited study in
Colorado.
Before I began work in 1966 no studies o f any kind had been
conducted on blue grouse in Arizona. There is little evidence why
grouse inhabit only a part of the range that appears to be suitable
for them. Perhaps a knowledge of their diet, in comparison to food
availability, might aid in understanding this problem.
The purpose of this study was to determine the food preferences
o f blue grouse in A rizo n a, and to compare th is inform ation w ith th a t
found in other states. This should give a better understanding of food
preferences of blue grouse over its entire range and aid in itsmanage
ment in A rizona.
Geology, Climate, and Vegetation
The study area was located in the White Mountains of east
central Arizona. This area is bounded on the west by Highways 60, 77,
89 from Salt River to Show Low, and on the north by Highway 60 from Show
Low to the Arizona New Mexico state line. It is bounded on the east
by the state line and on the south by the Mogollon Rim, Black River, and
Salt River (Figure 1). 4 central Arizona cast area in Mountain study Fig. 1. The White (Source. U. S. Geological Survey, 1956, State of Arizona Base Map) 5 The White Mountains are part of the Mogollon Plateau. They contain two o f the highest peaks in A rizona. Baldy Peak a t 11,490 feet and Escudilla Mountain at 10,955 feet. Other prominent peaks are
Mt. Ord at 10,920 feet and Green's Peak at 10,115 feet. The southern end of this mountain range is comprised of deep canyons and high ridges extending up to 9,500 feet. Blue grouse are found throughout this area, but usually above 8,500 feet (Figure 2).
Summer in the White Mountains are mild and winters are cold.
The warmest months are July and August when the average maximum tempera tures reach the mid 7 0 's . The coldest months are December and January, with an average minimum temperature of 10 F. About half of the 25-30 in. average precipitation comes during thunderstorms between the firs t week in Ju ly and the second week o f September. The remainder comes during mild spring and fall rains, and winter snows (Green and Sellers
1964).
Ponderosa pine (Pinus ponderosa) and mixed conifers occur up to about 8,500 feet. Spruce (Pices engelmannii) and Douglas fir
(Pseudotsuga menziesii) are found in the higher elevations. Open moun tain meadows consisting of bunchgrass-forb associations are found in the higher elevations. Shrubs are also interspersed throughout the area with the greatest abundance being found in burned and logged areas.
Light to heavy livestock grazing, and selective and clear-cut timber operations are the most common land uses that affect blue grouse in the
White Mountains. Fig. 2. Typical Arizona blue grouse habitat on Escudilla Mountain. CHAPTER 2
METHODS
Green's Peak was selected for vegetative analyses because it was an example of typical blue grouse habitat in the White Mountains of Arizona. Two transects to determine plant and animal food availa b ility were established and read one week before the September blue grouse hunt. The composition of the grass and forb vegetation, both in the meadow areas and in the timbered areas, was determined by the loop measurement method used by the United States Forest Service
(United States Forest Service 1965). This method of range survey is norm ally used to determine range trends but i t can also be used fo r determination of current vegetative composition. Use of this method made it possible to compare the vegetative composition on Green's
Peak to that in other parts of the White Mountains where the United
States Forest Service has transects.
Percentages of trees and shrubs in the timbered area were determined by a step point method (Costello and Schwan 1946). Two transect lines were randomly established through the timbered areas on the north and west side of Green's Peak. The technique consisted of taking ten paces and recording the nearest shrub or tree species as a hit. One-hundred hits were recorded along each transect line.
7 8
Insect population levels in the timber and meadow areas were determined during the same time that vegetation transects were read.
Species were recorded and given a rating of abundant, common, scarce, or ra re . These ra tin g were determined by the r e la tiv e number o f each species of insect collected in an insect net along the plant transects.
Unidentified species were collected and saved for future identification.
Blue grouse crops were collected at checking stations on Green's
Peak from 1967 to 1969, and on Escudilla Mountain in 1969. Additional crops were collected by Arizona Game and Fish Department personnel throughout the White Mountains from 1966 to 1969. At the checking sta tio n s crops were removed from grouse shot by hunters. A numbered tag was attached to each crop and it was immediately placed in formalin.
A corresponding number was placed on the checking station records show ing sex, age, date and location of collection. Each evening during the hunt, personnel of the Arizona Game and Fish Department gave me what ever crops they had collected during the day. These were treated in the same manner as crops collected at the checking station.
During the four years 135 crops were collected, of which 36 were empty. The crops containing food m a te ria l were opened and the contents were spread out on paper towels to remove excess formalin. The contents were separated by species and recorded. T h e ir volumes were measured to the nearest 0.1 cc by water displacement. Unknown species were measured and recorded as unknown, and put in to corresponding numbered envelopes for further identification by qualified personnel. Empty crops were disregarded. 9
The re s u lts o f food an alysis have been reported in various ways. Davison (1940), and G ilfillan and Bezdek (1944) believed that the frequency of occurrence gave the most accurate picture of food preferences. Martin, Gensch, and Brown (1946) considered that both frequency and volume were im portant. I used both percent frequency and percent total volume in this study because it was possible that a species could have a high frequency but a low volume, or a low fre quency and a high volume, depending on food preferences and availa b i l i t y .
Frequency of occurrence and percent total volume were based on the total sample of 99 crops in determining overall fall food pre ferences. In considering differences in the diets of adult males and females, juveniles, the total number of crops from the respective age and sex groups was used to compute percent frequency and percent t o t a l . volume. Only crops collected from Escudilla Mountain and Green's Peak in 1969 were compared when d iffe re n c e s in d ie ts were considered. CHAPTER 3
RESULTS AND DISCUSSION
Food A vailability
After the summer rains there was an abundance of plant growth and new hatches of common insects. By September most plants were in flower or bore fru it, and insect populations reached their maximum.
Consequently a large variety of food was available to blue grouse in the fa ll. The frequency of plants and insects which was available to blue grouse in September is shown in Table 1. In the bunchgrass-forb meadow types the vegetation was composed of 71 percent grasses and 29 percent forbs. Mountain muhly (Muhlenbergia montana) was the most common species of grass, and wild pea (Lathyrus arizonicus) was the most common forb. In lightly grazed stands this vegetation averaged from 12 to 20 inches in height. Ants (family Formicidea) and short horned grasshoppers (family Acrididae) were very abundant in this vege- tational type.
In the timbered types the understory vegetation was made up of
19 percent grasses and 81 percent forbs. The most abundant grasslike species was sedge (Carex sp.). The most common forb was the same wild pea found in the meadow types. Most of the plants in the timbered types had flowered or had made seed by September. The understory vegetation was covered by an overstory of 16 percent shrubs and 74 percent deci duous or coniferous trees. The most common shrubs were gooseberry
10 Table 1. Plant and animal matter available to Arizona blue grouse in September as revealed by examination of two 100 foot vegetation transects on Green's Peak.
Species Percent Frequency Parts A v a ila b le
Meadow Timber
Grass or g ra s s lik e
Muhlenbergia montana 17.0 ,L , F *
Koeleria cristata 16.0 L, F
Festuca arizonica 11.0 L, F
Carex sp. 9 .0 18.0 L, F
Bromus sp. 7 .0 2.0 L
Poa sp. 6.0 1.0 L
Sitanion Hystrix 5.0 L, F
Forbs
Lathyrus arizonicus 11.0 66.0 L, S, F, Fr
Erigeron macranthus 9 .0 L, S, F
Vicia americana 3 .0 2.0 L, S, F, Fr
Campanula ro tu n d ifo lia 2.0 L, F
Achillea lanulosa 1.0 L, S, F
Castilleja linariaefolia 1.0 L, S, F, Fr
Pseudocymopterus montanus 1.0 L, S, F, Fr
Taraxacum laevigatum 1.0 L, S, F, Fr
Thalictrum Fendleri 9 .0 L, F, Fr
Mentha arvensis 2.0 L, F 12
Table 1, Continued
Species Percent Frequency Parts A v a ila b le
Meadow Timber
Geranium Richardsonii 1.0 L, S, F, Fr
Smilacina racemosa 1.0 L, S, F, Fr
Shrubs
Ribes pinetorum 11.0 L, Fr
Rubus striqosus 3 .0 L
Lonicera Involucrata 2.0 L, Fr
Trees
Picea Engelmannii 4 8 .0 N
Populus trem uloides 29.0 L
Pseudotsuqa menziesii 7 .0 N
Animal M atter* **
Formicidae Abundant Common
A crididae Abundant Rare
Tenebrionidae Scarce Scarce
* F - Flowers Fr - Fruits L - Leaves N - Needles S - Stems ** Families only. 13
( Ribes pinetorum ) and raspberry ( Rubus s triq o s u s ) . The two most common trees were Engelmann spruce and quaking aspen ( Populus trem u lo id es).
Understory vegetation was completely lacking in areas where this over story was very dense. In the timbered habitats ants were the most com mon insects. Beetles (family Tenbrionidae) were scarce and grasshoppers were ra re .
Blue grouse in the meadow areas of the White Mountains had prin cipally grasses, forbs, and insects available for food. Birds feeding in the timbered portions had some grasses and insects available, but forbs, shrubs, and trees were the most abundant species.
P lan t Foods Eaten by Blue Grouse
The diet of blue grouse is quite variable. Stewart (1944) found
that the food habits of blue grouse varied from a simple winter diet made
up predominantly of coniferous needles, to a complex diet during the sum mer months o f green le a v e s , f r u it s , seeds, flo w e rs , animal m a tte r, and
coniferous needles. Beer (1943) found 63 genera of plants eaten by blue
grouse in northern Washington and Idaho, but only a few genera consti
tuted the major yearly diet. Boag (1963), studying the fall food habits
of blue grouse in north central Washington, found 5? genera of plant foods
and 14 families of insects. Only eight of these were abundant enough to
be considered significant. Dragness (1968) studies the fall food habits
of blue grouse in western Washington, and found 35 genera of plants and
three families of insects, of which seven were of major significance.
I found 18 genera of plants and six families of invertebrates in
the 99 crops I examined. A complete lis t of the plant parts eaten. 14 percent frequency, and the percent total crop volume for each food item is shown in Table 2. The firs t five plant groups had a frequency of at least 17 percent, and made up at least nine percent of the total crop volume. These were the primary plant foods taken by blue grouse in the
White Mountains, and they made up 80 percent of the total plant diet.
Ninety four percent of the crops examined contained one of these five plant groups. This shows the importance of these foods in the fall diet of blue grouse.
The most im portant foods were the w ild pea and vetch (V ic ia americana). Positive identification of these two species was difficult because the leaves were very sim ilar. Therefore, these two species were included in a single group. As a group they were found in 71 percent of the crops and made up 31 percent of the total volume. Leaves, stems, flowers, and fruits of these plants were eaten, with the leaves being the most common portion taken. These two plants were common in the tim bered areas of the White Mountains where they comprised 68 percent of the plants present. In the bunchgrass-forb meadow types, wild pea and vetch made up only 15 percent of the available forage, but they eere the most abundant forbs. High availability was probably responsible for the high utilization of this plant group. Stewart (1944) noted that vetch leaves were eaten by blue grouse in late summer, and Fowle (1960), studying blue grouse on Vancouver Island, British Columbia, found vetch taken by six percent of the adult birds during the summer. Boag (1958) found that the major summer food of blue grouse in Alberta was Lathyrus ochocleuchus. Table 2. Relative importance of food items found in crops from 99 Arizona blue grouse taken in September.
Species Percent Percent Parts Freq. Total V o l. Taken
Plant matter
Lathyrus arizonicus & 70.7 30.9 L, S , F ,* * Vicia americana * Fr
Rubus strigosus 29.3 13.8 L, Fr
Populus trem uloides 21.2 8 .4 L
Taraxacum sp.* v 20.2 10.5 L, S, F
Pseudotsuga menziesii 17.2 9 .8 N
Gramineae* 18.2 0.6 L
Pseudocymopterus montanus 15.2 0 .9 S, F, Fr
Geranium Richardsonii 8.1 0 .9 Fr
Arceuthobium campy!opodum 8.1 2 .9 S, Fr
Campanula r o tu n d ifo lia 7.1 1.6 F, Fr
Agaricaceae* 6.1 2 .9 S ta lk & Head
Ribes motigenum 5.1 3 .8 L, Fr
Picea Engelmannii 4 .0 0 .4 N
Trifolium subcaulescens 2.0 0 .7 L
Juniper communis 2.0 0 .7 Fr
Castilleja linariaefolia 1.0 0.6 Fr
Unidentified plant material 10.1 0.8 L 16
Table 2. Continued
Species Percent Percent Part Freq. Total Vol. Taken
Animal m atter** ** *
Formicidae 15.2 0 .4
A crididae 12.1 2 .5
Noctuidae 7.1 3.1
Philomycidae 1.0 0.7
H elicid ae 1.0 0.2
Tenebrionidae 1.0 0.2
G r it 11.0 1.2
* Genera combined because they were not always distinguishable.
** F - Flowers F r - F ru its L - Leaves N - Needles S - Stems
*** Family only
t 17
His study and mine show th a t w ild pea and vetch are the most common foods used by grouse a t opposite ends o f t h e ir range, but they are not used commonly in other areas. Differences in availability of these species, or higher availability of a more preferred species in differ ent portions of the blue grouse range, may be responsible for these differences in utilization.
The second most utilized food item was raspberry (Rubus strigosus). Leaves of this plant were used occasionally, but the ber ries were the important part taken by blue grouse. Raspberry was found in 29 percent of the crops and made up 14 percent of the total volume.
Availability of this plant varies in different areas of the White Moun tains. Raspberry was very abundant on Escudilla Mountain where it was part of a serai stage resulting from a severe forest fire in 1956. On
Burro Mountain it was abundant in areas that had been clear-cut logged.
On Green's Peak raspberry was scattered and shaded out by the dense stands of spruce and fir which cover the north and west sides of the mountain. In areas where raspberry was abundant massive berry crops were produced in favorable years. When this occurred blue grouse con gregated in these areas and ate large quantities of berries. Beer (1943) found that, where available, preference was given to the fru it of Rubus.
In some areas he found it being taken in large amounts, while only in trace amounts in other areas. He f e l t the d iffe re n c e in u t iliz a t io n was based entirely on availability. Fowle (1960) also found Rubus in large numbers of grouse collected on Vancouver Island in September. This genus has also been reported in blue grouse by Skinner (1927), in Yellowstone National IS
Park, F lin t (1928) in the Rocky Mountains, and Munro (1919) in B r itis h
Columbia.
Several authors think that berry crops have an affect on the fall migrations of blue grouse. Marshall (1946) believed that fall migration in southern Idaho was determined by the depletion of the berry crop on the summer range. Heebner (1956) found more berries on the summer range in late summer than at higher elevations in the northern Rocky Mountains, as did Bauer (1962) in north central Washington. This indicated that fall migration was not connected with berry crops. In Colorado, Rogers (1968) found that weather and food conditions influenced elevational movements.
In years when there was a preferred food supply (berries or mast) at low e r elevatio n s upward movement to co n ifers was delayed fo r several weeks and occasionally through the winter. In Arizona no seasonal migrations of blue grouse appeared to occur as they do in the northern grouse areas.
However, in years when raspberry produced abundant berry crops at lower elevations, birds moved into these areas to feed on the fru it. After
these berry crops were exhausted the birds dispersed back over the entire
range. High utilization by grouse during years of abundant berry crops
shows that raspberry is a highly preferred plant. Localized differences
in availability are probably what cause differences in utilization of this
species;
Aspen (Populus tremuloides) leaves were the third most frequent
item found in blue grouse crops, with a frequency of 21 percent. They
made up eight percent of the total volume. The availability of aspen in 19
the White Mountains varied locally, but this species was common through out the timbered areas. On Green's Peak aspen made up 29 percent of the tree overstory. This genus also was present in the understory as seedlings. During this study birds were observed feeding on aspen both on the ground, and also while perched in mature trees. The availability of this genus, plus the fact that it provides available forage in an over sto ry th a t has shaded out more d e s ira b le understory veg etation in many areas, makes aspen an important food for blue grouse in Arizona. Beer
(1943) and Stewart (1944) reported that in early summer aspen leaves were utilized by blue grouse in eastern Washington and northern Idaho.
The genus Taraxacum was the fo u rth most im portant group o f foods
taken by blue grouse in the White Mountains. It had a frequency of 20
percent and comprised 10.5 percent of the total crop volume. All plant
parts in th is genus were s im ila r in appearance, and in many instances
only pieces were found in the crops, making specific identification
difficult. Definite identification was made of two dandelions (Tarax
acum officinale and Taraxacum laevigatum) but because these two species
could not be identified positively in every instance they were grouped
together. Both species of dandelion were distributed throughout the
White Mountain area with Taraxacum laevigatum found in one percent of
the vegetation in the meadow areas, and Taraxacum officinale present
in tra ce amounts. Both species were found in la rg e r amounts in lo c a liz
ed disturbed areas such as along roads or in freshly logged areas. Grouse
were observed feeding on dandelion along roads while they collected g rit. 20
Dandelion was found in 20 percent of the blue grouse crops, yet because of its sparse availability a feeding bird had to seek it out. Some birds also ate la rg e amounts o f dandelion. One crop con tained 24.3 cc of leaves and flowers. This indicated that when dande lions were available they were a highly preferred species.
The use o f dandelion by blue grouse has also been reported in the Rocky Mountains by Stewart (1944). He found the leaves to be the most important food item. Beer (1943) found blue grouse in Idaho took the following genera of the family Compositae: Agoseris, Arnica,
E rig ero n , and Taraxacum. He found they ate them re g u la rly but never in large quantities. Dragness (1968) also found this to be the case in western Washington. Boag (1963) found the leaves and flowers of dandelion in a large number of crops from birds collected in eastern
Washington in the fa ll. He thought the reason for this high u tiliza tion was because dandelion produced tender new growth in the fa ll.
This new growth was preferred by blue grouse. Nutritive value is another possibility for the high utilization of dandelion which should also be considered. Leopold (1933) stated that one of the things which governs what foods an animal w ill select is what its current physiolo gical processes require. However, since little is know about the nutri ent requirements of grouse the reason for their preference for dande
lions is obscure.
Many authors have reported the importance of evergreen needles
in the diet of blue grouse, especially in winter (Stewart 1944), Boag
(1963), Flint (1928), Munro (1919), Neilson (1926), Simpson (1935), 21 Rogers (1960) and Dragness (1 9 6 8 ). Douglas f i r was found by Beer
(1943) to be the most important plant food of blue grouse. He found that the distribution of Douglas fir agreed with the distribution of the genus Dendragapus, except fo r an area in Canada where grouse f o l low the range of Abies. Douglas fir was not abundant in Arizona but it did occur commonly in the White Mountains. It was found in associ ations with spruce at higher elevations, and with mixed conifers in lower areas. Douglas fir was found in 17 percent of the crops and it made up 10 percent of the total volume. I assume that both frequency and percent total volume would increase in winter as the availability of other food items decreased. Douglas fir is probably the most im portant year round food item in the diet of blue grouse, but in the fall its use is reduced because of the increased availability of other p la n t and animal species.
The remaining 20 percent of the plant food taken by blue grouse in the White Mountains was comprised of 13 other genera. Two of these, grass and Mountain Parsley (Pseudocymopterus montanus), were found in a relatively high number of the crops examined, but made up a very small percentage of the total volume. Grass was found in 18 percent of the crops. I believe that the reason for this high frequency of occurrence is based on the availability of grass, and the plant associ ations it is found with in the blue grouse range. Grass species were the most abundant plant group in the meadow areas where they made up
71 percent of the plant community. Grass made up 19 percent of the
plants in the timbered areas. The second most common species in the 22 meadow areas was the w ild pea and vetch group, and th is same group
was the most common group in timbered areas. W ild pea and vetch both
tra il along the ground and become entangled with the abundant grass
species. When a blue grouse feeds on a wild pea or vetch plant it is
possible that any grass entangled in it w ill also be pulled free and
eaten. I believe that grass is not selected. It is acquired inciden
tally while grouse are feeding on the highly preferred wild pea and
vetch. This explains why the leaves are the most common portion taken.
This is the portion of the grass plant which grows in association with
the w ild pea and vetch p la n ts .
Parsley was found in only one percent of the vegetation but
occurred in 15 percent of the crops examined. The seeds were the most
common portion taken, but because of their small size made up only 0.9
percent of the total volume. Beer (1941) reported that the seeds of
Arctostaphylos, Prunus, Crataegus, and Symphoricarpos were used by blue
grouse as a substitute for g rit, and that complete substitution of hard
seeds for grit was fairly common. Fowle (1960) found that gizzards col
lected in June contained g rit as the common hard constituent, but in
September it was largely replaced by hard seeds. Mountain Parsley seeds
are very hard and have sharp edges so they may serve as g rit in the White
Mountains.
The remaining species of plant foods found in blue grouse crops
in Arizona appear to be of little significance in the consideration of
the fall diet. They were found infrequently and made up only small por
tions of the total volume. However, the importance of these species (like 23
dandelions) is d ifficu lt to determine because of a lack of knowledge on the nutritional requirements of blue grouse. Some, or a ll, of these species may be selected to meet special physiological requirements, and any one of them could be very important in blue grouse survival.
One of these species, spruce, was abundant in the White Mountains but s till received little use. Spruce was found by Bailey (1928) to make up a good portion of the diet of blue grouse in southeastern Alaska, but was found to be of little importance in eastern Washington and northern
Idaho by Beer (1 9 4 3 ), and Boag (1 9 6 3 ). Simpson (1935) found th a t grouse in captivity passed up spruce if fir , pine, or hemlock was present. This shows that spruce is taken in large quantities only when other conifers are not available. This indicates that grouse diets vary considerably as more preferred species become available, but that plant availability alone does not always determine which plants w ill be utilized. In some instances preference w ill be given to less available plants if they meet the nutri tional requirements of the bird better than the more abundant species.
Analyses of plant parts eaten by blue grouse in the White Moun tains, in September, showed the most important portions to be leaves, stems, and flowers. These items made up 61 percent of the total volume taken. Berries and needles both made up 16 percent. Plant parts compris ed 92.9 percent of all the foods eaten by grouse in September (Table 2).
Dragness (1968), working in western Washington, found berries to be the most important parts taken. They made up 54 percent of the total volume.
Flowers, leaves, and stems comprised 30 percent, needles 15 percent, and 24 insects less than one percent. Plant parts comprised 99.7 percent of all foods eaten. This shows that blue grouse food habits are generally very similar, but that there is a wide variation in individual items u t iliz e d .
Animal Foods Eaten by Blue Grouse
Animal matter made up 7.1 percent of the total volume eaten by blue grouse in Arizona (Table 2). Six families of invertebrates were eaten with ants, grasshoppers, and caterpillars (family Noctuidae) the most common. Ants and grasshoppers were abundant in the grass covered meadows of the White Mountains in September, and their high utilization can be attributed to their high availability. Stewart (1944) found ani mal foods present in seven percent of the crops he collected during August and September. Fowle (1960) found insects comprised two to three percent of the summer food, primarily of young birds. Beer (1943) found that ani mal foods comprised 1.7 percent of the annual adult diet of blue grouse, but that they were very important to juvenile birds. In Arizona insects were of minor importance to adult blue grouse. However, data on food pre ferences of juveniles indicated that insects might be quite important to this segment of the population.
G rit
G rit, in the form of gravel, was present in 11 percent of the
crops, but due to its small size made up only one percent of the total
volume. The size varied from sand to jagged pieces of rock one-quarter
of an inch long. Mountain Parsley seeds also might be used for grit as 25 has been discussed previously. These seeds were found in 15 percent of the crops. Dragness (1968) noted an increased utilization of grit as more conifer needles were eaten. Possibly more g rit might be found in the crops of Arizona blue grouse later in the fa ll.
Water
The importance of open water for blue grouse is questionable.
Wing, Beer and Tidyman (1944) found that blue grouse were often observ ed around springs and water holes, but they did not know if grouse v is it ed water regularly. They fe lt that berries might provide water as well as food. Beer (1943) found that an abundant supply of wild fruits would supply needed water, but that open water was used whenever it was available. Fowle (1960) saw grouse drink water, but thought that avail able water was not important when berries or other succulent food was available. Water was unavailable in many areas of the White Mountains.
In areas where it was available birds were never observed utilizing it.
No tracks were ever observed around water tanks or springs. Some areas inhabited by blue grouse in Arizona have no available water except after rainy periods. This suggests that they are able to acquire needed water in the vegetation they eat. However, more information needs to be gath ered on the water requirements of blue grouse, and the amount of water provided by plant and animal m aterial.
Crop Volume
The individual crop volume varied from empty to a high of 53.9 cc in a single crop. The average adult crop contained 6.0 cc of food com pared to 5.1 cc in the juvenile crop. Hence, adults ate only slightly 26 more than juveniles. This difference was probably due to the larger size of the adult birds. Dragness (1968) found that females ate more than adult males in western Washington. This also appeared to be the case in Arizona. The average crop volume for adult males was 5.3 cc o f food, compared to 7 .4 cc fo r a d u lt fem ales.
Differences in Diets of Adults
Differences between adult male and female blue grouse diets have been reported by Beer (1 9 4 3 ), Dragness (1 9 6 8 ), and Mussehl (1960)
These differences are caused by an altitudinal separation of the two sexes in the fa ll. Various investigators have established that in much of the blue grouse range an upward fa ll migration is made by blue grouse from the summer to the winter range (Mussehl 1960, Beer 1943, Marshall
1946, and Heebner 1956). The adult males are the firs t to leave the summer range. They are followed later by the females with their broods.
This migration causes birds to be in different vegetational zones at the same time of year. This affects their diets because of differences in the availability of specific species at different elevations.
I observed no evidence of either a spring or fall migration of blue grouse. I found similar densities of birds at the same elevations in the s p rin g , summer, and f a l l . The only movements o f grouse I observ ed were in years of abundant raspberries. In these years grouse concen trated in areas where berries were abundant, and remained until the berry crop was completely utilized. In years when raspberries were not pro duced grouse remained spread throughout their range and no concentrations were noted. V
Even though annual altitudinal migrations did not appear to occur in Arizona, differences in the diet of adult males and females were observed. These differences were caused by a separation of the
sexes which resulted from a difference in habitat requirements. The
females spent most of their time in the meadow areas where there was
abundant food and cover for their broods. The males were solitary
at this time of year and remained in the dense timbered areas. Because
of differences in availability of the food species in these two areas,
there were differences in diets of the sexes.
In the timbered areas the understory was composed of 81 percent
forbs and 19 percent grasses. The most available forbs were wild pea
and vetch. The overstory was made up of 74 percent trees and 16 per
cent shrubs. Spruce and aspen were the two most common trees, and
spiny gooseberry (Ribes pinetorum) and raspberry were the most common
shrubs. The diet of the adult male blue grouse corresponded very close
ly to the availability of plants in the timbered areas. Forbs, mostly
wild pea and vetch, made up 47.2 percent of the adult males diet, and
shrubs, principally raspberry, comprised 11.6 percent. Trees, princi
pally Douglas fir and aspen, made up 40.9 percent. All plants eaten
by adult male blue grouse were available in the timbered areas. They
remained in these areas because their food preferences were completely
met in this habitat type.
Diets of the adult female corresponded very closely to the vege
tation available in the meadow areas where forbs made up 29 percent of 28 of the forage, and grasses made up 71 percent. The adult female diet was composed of 74.3 percent forbs and 24.7 percent shrubs. Wild pea and vetch received the heaviest utilization because they were the most available forbs in the meadow areas. Raspberry was the most used shrub.
Aspen and Douglas fir made up only 0.7 percent of the total volume of forage used by a d u lt fem ales. This shows th a t a d u lt females did most of their feeding in the open meadows where their young had adequate food and cover. The availability and utilization of trees by adult males accounts for the difference in forb use between the sexes. Rasp berry was important to both sexes. Plants were normally found in the transition areas between the meadows and the timber and were available to both adult males and females.
During this study I never observed an adult female blue grouse with her brood in any vegetative cover lower than 12 in. in height
(Figure 3 ). The only birds observed in more open a re a s , or in the tim ber
♦ed areas, were adult males. This indicates that females with broods pre
fer tall grassy areas. Neither adult males or adult females used much
grass in their diets. Therefore, grass must be important for other
reasons.
Mussehl (1963) found that herbaceous cover was particularly
important during the firs t six weeks of life for the young grouse, and
that blue grouse broods selected areas during this time in which native
bunchgrasses and associated forbs were dominant. He found the height of
this cover was related to the height of the brood hen (10-14 in .), and 29
Fig. 3. Typical vegetative height selected by blue grouse hens with broods. 30 that hens were usually found in ground vegetation high enough to con ceal all except their head and part of their neck. A reduction of this height created an insecure brood habitat and affected brood survival.
Bailey (1928) found in New Mexico, that blue grouse increased in areas where liberal ground cover was allowed to become reestablished because it provided cover for nesting birds and young birds. Bauer (1962) found that one of the major items controlling hatching success and summer popu lations was the condition of the vegetation in early summer. The impor tance of good range condition in the blue grouse range has also been noted by Zwickle (1958) and Bendell (1955). These studies show that the importance of grass is from the standpoint of brood production, cover, and food. This explains why the adult female diet corresponded closely with the forbs found in the meadow areas during the time she had a brood. These meadow areas met the food and cover requirements of the juvenile birds better than the timbered areas.
D ifferen ces in D iets Between Adults and Juveniles
Differences in the diets of adult and juvenile blue grouse have been reported by Beer (1943). He found that animal material comprised *
71 percent of the diet of three week old birds. The quantity of insects then decreased until the birds were about six weeks old. After this, the feeding pattern of the juvenile birds conformed to that of the adults.
He thought that a good supply of insects during the firs t month of the chick's life was quite important, and that the lack of insects was probably why there were a few blue grouse found in solid stands of timber. 31
Mating activity in the White Mountains was observed during the last week of May and the firs t week of June. Egg laying and incubation take about one month (Bendell 195 5), so chicks would hatch about the first week of July. This made juvenile birds collected in September eight to nine weeks of age. According to Beer's findings on the diets of juvenile birds, their diets should conform closely to that of the adult birds. A comparison of the frequency and the percent of the total volume of the five major groups of food and insects, found in adult and juvenile crops is shown in Figure 4. The utilization of wild pea, vetch, and raspberry was very similar between juveniles and adults. This was a result of the availability of these genera to both age groups.
Aspen was u t iliz e d more by adu lts than ju v e n ile s , p rim a rily be cause of the differences in adult male and female feeding habits. The solitary adult males spent most of their feeding time in the timber where aspen was more available than it was to juvenile birds which fed in the meadow areas.
Dandelion was taken more frequently by juvenile birds, but adults ate larger amounts. This was probably because juvenile birds experimented with a large variety of different foods.
Douglas fir made up a very small portion of the total crop volume of both adults and juveniles. In adults this low use of needles at this time of year was caused by an increase in the availability of other plants.
Juveniles did not eat Douglas fir because they spent most of their time in
the meadow areas where it was not available. 32
Adults
Juveniles
o 70
CO ZD CO 13 LU O Q i—< M CO Z o z ID LU M «C CO ID z: I - H o o z: O f 1 - 4 o LU o . ANIMAL MATTER Fig. 4. A comparison of the major plant and animal foods eaten by 31 adult and 51 juvenile blue grouse. 33 Insects were found in 52.8 percent of the juvenile crops and 19.4 percent of the adult crops. They comprised 13.5 percent of the total juvenile diet. The most common insects eaten were ants and grasshoppers. Apparently juveniles prefer insects when they are available. The percentage of insects found in the crops of Arizona blue grouse was much higher than has been found by any o th er author working on the fall diets of blue grouse. This difference was due to Arizona's fall climate. September in Arizona is a much more pro ductive month for insects than it is in northern portions of the blue grouse range. This makes insects more available to juvenile birds at this time of year in Arizona. Dragness (1968) found this to also be true in western Washington where freezing temperatures were later than in the inland areas. I noted during this study that blue grouse were seldom seen in areas which lacked good cover. Adult males remained in the dense tim bered areas, and adult females with broods were always found feeding in the open meadows. Their respective diets corresponded closely to the areas they were observed in. If hens brought their young to the meadow areas to feed, these areas must provide essential foods which were not available in the timber. A comparison of the foods available in the timber and the meadow areas shows that there were two major groups of food which were more abundant in the meadows. One was grass and the other was insects, principally grasshoppers (Table 1). A com parison of food available and food utilized (Table 2) showed that grasses were the most abundant food group in the meadows but were utilized the least. Insects were also abundant in the meadows and were taken by ju v e n ile b ird s . Even in e a rly f a l l over o n e -h a lf the juvenile birds were eating insects, and 13.5 percent of their diet was made up of this food group (Figure 4). Grasses appeared to be used-primarily for cover while the juvenile birds fed on insects. Apparently the reason for the use of the meadow areas by juvenile grouse is because of the abundance of insects that are produced in these areas. Beer (1943) thought th a t the presence o f a good supply o f insects during the firs t month of the chicks life was quite impor tant, and that a lack of insects in solid stands of timber was pro bably the reason why few blue grouse were found in these areas. In a study of the nutritional value of insects Stiven (1961) found that a blue grouse chick would obtain less useful energy per gram of plant food than it would per gram of invertebrate food. Mussehl (1963), found in Montana, that blue grouse hens selected areas to raise their broods in which the ground vegetation was 10-14 inches high. He con sidered that the selection of these sites by the hen was made mainly for cover, but feeding was the major activity and insects appeared to be abundant in these areas. These studies show that insects provide the protein which blue grouse chicks need for rapid growth. After growth slows down, or is attained, the protein needed for body mainte nance can be obtained from plant matter, as it is by the adults. It 35 seems lo g ic a l th a t as long as a high p ro te in food source, such as in sects, is available juvenile blue grouse w ill take advantage of it. If blue grouse chicks do not have insects available at the time of hatching it could have an affect on survival. Since insects are im portant to juvenile blue grouse it appears that tall grass areas are also important. These areas not only provide needed cover for chicks after hatching, but they also provide areas of abundant insects, especially grasshoppers. During the period when most of the blue grouse hatch in the White Mountains (June 15 - July 15) the minimum temperatures are s till very low. The average minimum temperatures at 9,000 feet at this time of year is 31.7 degrees (Green and Sellers 1964). This temperature is low enough to prevent grasshoppers from hatching except in protected areas. Norman, Kemp, and T a y le r (1957) found th a t the number o f nights without frost in tall grass cover was only 50 percent of those in short grass. This means th a t in areas protected by t a l l grass cover more in sects would be hatched. If areas of tall vegetative cover are lacking it is possible that the insect population could be too low to support the needs of the newly hatched blue grouse chicks. This phase of blue grouse ecology needs further investigation because it appears that a lack of insects at the time of the blue grouse hatch could be a possible limiting factor of blue grouse population. 36 Differences in Diets Between Areas The importance of careful sampling in studying the food habits of blue grouse has been pointed out by Beer (1941) and Dragness (1968). Differences in availability of specific food items in different loca tions can cause diets to vary considerably. In 1968 and 1969 I noted that the raspberry on Escudilla Mountain produced an abundant berry crop. Grouse moved into these areas and fed extensively on these berries. During the same years the raspberry on Green's Peak produc ed very few berries. Checking stations were established to collect crops from grouse on these two mountains so that comparison of the d ie ts could be made. The comparison shows th a t blue grouse d ie ts vary significantly when a preferred food becomes readily available (Figure 5). The diet of grouse on Escudilla Mountain in September, 1969, was composed of raspberries and forbs. Those on Green's Peak had a high per centage of Douglas fir needles and insects. Apparently the availability of raspberries caused the birds on Escudilla to eat large quantities of berries and forbs which were readily available. On Green's Peak, where raspberries were not available, the birds followed what I assumed to be a normal fall pattern in their choice of foods. An increase in the use of needles and a decrease in forbs eaten shows that by September they had started the change from a summer diet of forbs to a winter diet of needles. Use of insects remained high, but examination of the specific insects which were being eaten showed that caterpillars (family Noctuidae) were the most common. These caterpillars live in the trees where they would be available only to blue grouse which spend most of F ig . . ig F PERCENT TOTAL VOLUME 5 A oprsn fos ae b bu gos o Esudil and illa d scu E on grouse blue by eaten foods f o comparison A . re' Pa i etme, 1969. September, in Peak Green's —Jog 37 38 their time in the tree tops. Blue grouse feeding on the ground would not have access to them. This shows that blue grouse diets can change from location to location due to differences in availability of specific food items. D ifferen ces in D iets Between Arizona Grouse and Northern Grouse Blue grouse diets in the White Mountains of Arizona vary signi ficantly from the diets of blue grouse in the northern portions of the blue grouse range. Boag (1963) stated that: (1) The diet of most galli- forms is extremely varied, and ( 2) major food items in the diet of a particular species in one region might be of little importance, or en tirely absent from, the diet of the same species in another region. All studies of foods eaten by blue grouse have shown an extreme variation in specific species of plants and invertebrates taken. (Beer 1943, Boag 1963, Dragness 1968). Evidence that major food items in the diet of a particular spe cies in another region can be seen in a comparison of the five major food groups found in the White Mountains of Arizona, and those found by Boag in north central Washington (Table 3) . For example, the w ild pea and vetch, which are the most important plants in Arizona are not among the top five food items in Washington. Boag found only a trace of this food item. The most important food item in Washington, Larix, does not occur in Arizona. The top food items from the two respective states illustrate that the major food items in one region can be of negligible importance, or entirely absent from, the diet of the same species in another region. e 39 Table 3. A comparison of the five major food items eaten by blue grouse in north central Washington* and the White Mountains of Arizona. Washington Arizona 1. Lari x. occi dental i s 1. Lathyrus arizonicus & Vicia americana 2. Pseudotsuga menziesii 2. Rubus strigosus 3. Abies sp. 3. Populus tremuloides 4. Taraxacum vulgare 4. Taraxacum sp. 5. Arctostaphylos uva-ursi 5. Pseudotsuga menziesii Boag, D. A. 1963. Significance of location, sex, and age to the autumn d ie t o f blue grouse. J . W ild !. Mgmt. 2 7 ( 4 ) :555-562. 40 Douglas fir was important in both regions, and was among the top five categories. Taraxacum was also eaten in both areas with only the species being different. Raspberry fru its, which are very important to blue grouse in Arizona, are not among the major food items in the diet of grouse in north central Washington. Instead the berries of Arctostaphylos are very important. The only Rubus found by Boag was in trace amounts. This shows how a food item can be a major food item in one portion of the range and only be of negligible importance in another region. Arctostaphylos, which was very important in Washington, was also an other major food item which was entirely absent in the diet of blue grouse in Arizona. Even though wide variation exists between individual species, sim ilarities in the types of food eaten in both areas can be seen. Grouse in Washington ate Larix, Pseudotsuga, and Abies needles, while birds in Arizona used Pseudotsuga needles. Rubus was the main source of berries in Arizona, while the berries of Arctostaphylos were the most common berries taken by blue grouse in Washington. Leaves, stems, flowers and fruits of forbs are represented by Taraxacum in Washington, and Lathyrus, Vicia, and Taraxacum in Arizona. Generally the same types of foods are eaten, but differences in availability determine what speci fic items w ill be taken in various portions of the range. CHAPTER 4 CONCLUSION The results of this study show that blue grouse have an abundance of food species available in the fa ll. This abundance causes the diets of grouse in different locations to vary due to localized differences in availability of individual species. Five groups of foods were found to be eaten whenever they were available. Because these species were selected from an abundance of available foods, they were considered to be preferred. Other authors, study ing the winter diets of blue grouse, have found that the blue grouse lives on only one kind of food (Douglas fir) throughout the winter. Therefore, in the fall when five preferred foods are available, blue grouse should have an u n lim ite d food supply. Other authors have also found that heavily grazed areas, and large expanses of continuous timber, are unfavorable for blue grouse. Hens require open areas of ta ll herbaceous vegetation for nesting and rearing their broods. The results of this study show that these tall grass areas are highly preferred by juvenile blue grouse, and insects (grasshoppers) are the food item they can obtain in these areas. Grass hoppers could be very important to the survival of blue grouse chicks. It is possible that in areas where tall vegetative cover does not exist insufficient numbers of insects during the period when most of the 41 42 blue grouse hatch might have an effect on the survival of juveniles. Research should be conducted to determine if this is a lim iting factor on blue grouse populations. Both grazing and fire can have an effect on vegetative cover. Much of the grouse range in Arizona, especially on the Kaibab Plateau, has been grazed for many years. In many of these areas tall vegetative cover is lacking and blue grouse populations are very low. It is possi ble th a t under good range management p ractices t a l l v e g e ta tiv e cover could be restored and grouse populations might increase. Also, throughout much of the grouse range forest fires have been controlled for many years. This protection has resulted in thick continuous stands of spruce-fir in areas that formerly had many small grassy openings and meadows. If log ging or controlled burning was used to reestablish these small openings, grouse also might increase in these areas. In other portions of the blue grouse range better grazing prac tices in meadow areas where livestock and blue grouse are both found has been encouraged. Also, timber practices such as controlled burning, or the creation of small openings in large expanses of continuous timber by clear-cut logging, have been found beneficial to the production of blue grouse. These same land management p ractices should be encouraged in Arizona if blue grouse are going to be considered an important game bird in this state. LITERATURE CITED Bailey, F. M. 1928. Birds of New Mexico. New Mexico Dept, of Game and Fish, Santa Fe. 807 pp. ______. 1939. Among the birds in the Grand Canyon country. United States Government Printing Office, Washington D. C. 211 pp. Bauer, R. D. 1962. Ecology of blue grouse on summer range in north- central Washington. M. S. Thesis, Washington State Univ., Pullman. 81 pp. Beer, J. R. 1941. Food habits of the blue grouse. M. S. Thesis, Washington State Univ., Pullman. 48 pp. . 1943. Food habits of the blue grouse. J. Wild!. Mqmt. 7Tl):32-44. Belding, 1892. Food of the grouse and mountain quail of central C a lifo rn ia . Zoe 3 (3 ):2 3 2 -2 3 3 . Bendell, J. F. 1955. Age, breeding behavior and migration of sooty grouse. Trans. N. Am. Wild!. Conf. 20:367-381 ' Boag, D. A. 1958. Biology of the blue grouse of the Sheep River area. M. S. T h esis, Univ. o f A lb e rta , Edmonton. 97 pp. ______. 1963. S ig n ific a n c e o f lo c a tio n , y e a r, sex, and age to the autumn diet of blue grouse. J. Wild!. Mgmt. 27(4):555-562. C o s te llo , D. F . , and H. E. Schwan. 1946. In Conditions and trends on Ponderosa Pine ranges in Colorado." National Academy of Sciences. 1962. Basic problems and techniques in range research; National Research Council, Washington D. C. 341 pp. Davison, V. E. 1940. A field method of analyzing game bird foods. J. Wild!. Mgmt. 4(2):105-116. Dragness, J. C. 1968. A study of the food habits of the blue grouse in western Washington." M. S. Thesis, Washington State Univ., Pullman. 36 pp. Flint, H. R. 1928. Some Rocky Mountain grouse. Amer. Forests. 34(10):600-603. 43 44 Fowle, D. C. 1960. A study of the blue grouse (Dendraqapus obscurus (Say)) on Vancouver Island, British Columbia. Can. J. Zool. 38(3):701-713. G ilfillan, M. C., and H. Bezdek. 1944. Winter foods of the ruffed grouse in Ohio. J. Wild!. Mgmt. 8(3):208-210. G ra te r, R. K. 1937. Check l i s t o f birds o f Grand Canyon N ational Park. Nat. H is t. B u ll. No. 8. Grand Canyon Natural H isto ry A ssociation . 55 pp. Green, C. R., and W. D. Sellers (Editors). 1964. Arizona Climate. Univ. of Ariz. Press, Tucson. 503 pp. Heebner, G. C. 1956. Life history of the blue grouse in the northern Rocky Mountains. M. S. Thesis, Univ. of Idaho, Moscow. 51 pp. Leopold, A. . 1933. Game Management. Charles Scribner's Sons, New York 481 pp. M a rs h a ll, W. H. 1946. Cover preferen ce, seasonal movements and food habits of Richardson's grouse and ruffed grouse in southern Idaho. Wilson B ull., 58(1):42-52. M a rtin , A. C ., R. H. Gensch, and C. P. Brown. 1946. A lte rn a tiv e methods in upland gamebird food a n a ly s is . J. W ild !. Mgmt. 10(1):8-12. Mearns, E. A. 1890. Observation on the avifauna of portions of Arizona. Auk. 7(l):45-55. Mem*am, C. H. 1890. Annotated lis t of birds of the San Francisco Mountain Plateau and the desert of the Little Colorado River, A rizona. North American Fauna No. 3 :8 7 -1 0 1 . Munro, J . A. 1919. Notes on some birds o f the Okanogan V a lle y , British Columbia. Auk. 36:65-67. Mussehl, T. W. 1960. Blue grouse production, movements, and popu lations in the Bridger Mountains, Montana. J. Wild!. Mgmt. 24(1):60-68. . 1963. Blue grouse brood cover selection and land use implications. J. Wild!. Mgmt. 27(4):547-555. Neil son, J. A. 1926. Bird notes from Wheatland, Wyoming. Condor. 28:99-100. 45 Norman, J. T ., A. W. Kemp, and J. E. Tayler. 1957. Winter Temperatures in long and short grass. Met. Mag. 86:148-152. Pettingill, 0. S. Jr. 1953. A guide to bird finding west of the Mississippi. Oxford Univ. Press, New York. 709 pp. P h illip s , A ., 0. M a rs h a ll, and G. Monson. 1964. The birds o f A rizona. University of Arizona Press, Tucson. 212 pp. Phillips, P. 1937. Dusky grouse in the Chuskai Mountains of north eastern Arizona and northwestern New Mexico. Auk. 54:203-204. Rogers, G. E. 1968. The blue grouse in Colorado. Colorado Game, Fish and Parks Dept., Tech. Pub. 21. 63 pp. Simpson, G. 1935. Breeding Blue Grouse in Captivity. Trans, of the Twenty-first American Game Conference. 218-219. Skinner, M. P. 1927. Richardson's Grouse in Yellowstone Park. Wilson Bull. 39:212-213. Stewart, R. E. 1944. Food habits of blue grouse. Condor. 46:112-120. Stiven, A. E. 1961. Food energy available for and required by the blue grouse chick. Ecology. 42(3):547-553. United States Forest Service. 1965. Range Analysis Field Guide. United States Dept, of Agri. Forest Service Southwestern Region. F.S.H. 2212.01 R3. 153 pp. United States Geological Survey. 1956. State of Arizona base map. United States Dept, of Interior, Washington D. C. Wing, L . , J. Beer, and W. Tidyman. 1944. Brood habits and growth o f "Blue grouse." Auk. 61:426-440. Zwickel, F. C. 1958. Fall studies of forest grouse in north central Washington. M. S. Thesis, Washington State Univ., Pullman. 129 pp.