An evaluation of white-tailed deer (Odocoileus virginianus couesi) habitats and foods in Southern Arizona
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Authors White, Robert Wesley, 1928-
Publisher The University of Arizona.
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Link to Item http://hdl.handle.net/10150/553903 AN EVALUATION OF WHITE-TAILED DEER
(ODOCOILSUS VIRGINIANUS COUESl)
HABITATS AiiD FOODS IN SOUTHERN ARIZONA
by
Robert W, White
A Thesis Submitted to the Faculty of
WILDLIFE MANAGEMENT
In Partial Fulfillment of the Requirements For the Degree of
MASTER OF SCIENCE
In the Graduate College
UNIVERSITY OF ARIZONA
19 5 7
19791 1957 5 I
STATEMENT BY AUTHOR
This thesis has been submitted in partial fulfillment of re quirements for an advanced degree at the University of Arizona and is deposited in the University Library to be made available to bor rowers under rules of the Library.
Brief quotations from this thesis are allowable without special permission, provided that accurate acknowledgment of 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 their judgment the proposed use of the material is in the interests of scholarship. In all 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:
Zoology This study was financed by the Arizona Cooperative
Wildlife Research Unit, which is cooperatively main tained by the following organizations: The University of Arizona, The Arizona Game and Fish Department, The
U. S. Fish and Wildlife Service and The Wildlife Manage ment Institute* TABLE OF CONTENTS
Chapter I INTRODUCTION ------1
Description of study areas------— 2 Climate------3
Chapter II CLASSIFICATION Aim DISTRIBUTION OF ARIZONA WHITE-TAILED DEER— — — — ------6
Altitudinal distribution ——— ———————— — — —— 11 Distribution by plant associations — ------11
Chapter III ANALYSIS OF FEEDING HABITS — ------13
The feeding-minute technique ------— 14 Methods------14 Advantages of the technique ------— ------1$ Disadvantages of the technique ------16 Results of feeding-minute method ----— — — — 16 Summary of the feeding-minute technique ------28 Collection and analysis of stomach samples — — 29
Chapter IV ANALYSIS OF RANGE CONDITIONS------35
Browse transects------35 Index for acorn production------. 38 Comparison of deer ranges by pace-transect and pellet-group counts ------47 Salts and minerals — ------47 Importance of open wa t e r ------48 Dense chaparral------49 High altitude parks -— ------49 Effects of fire on deer range------50 Cattle-deer competition -----— ------51
Chapter V PRODUCTIVITY ------53
Breeding season------53 Analysis of ovaries------54 Buck:doe and doe:fawn ratios ------56
SUMMARY------i------58
LITERATURE CITED------59 LIST OF TABLES
Number Page
1* Use of noil-leguminous browse species in the low-altitude study areas (4,000 - 5,500 ft.) June 15, 1955-February 1, 1956- 21
2. Use of leguminous browse species in the low-altitude study areas (4,000 - 5,500 ft.) June 15, 1955 - February 1, 1956---- 22
3. Use of forbs and grasses in the low-altitude study areas (4,000 - 5,500 ft.) June 15, 1955 - February 1, 1956.------23
4. Use of browse species in high altitude study area (8,000 - 9,000 ft.) July 1 - December 1, 1955------24
5. Use of forb and grass species in the high altitude study area (8,000 - 9,000 ft.) July 1 - December 1, 1955.------24
6. Per cent of total observed feeding time spent on browsing of Fouquieria splendens and rainfall record for Florida Canyon, Santa Rita Mountains, 1955*------25
7. Percentage of total feeding time on browse, forbs and grasses Florida Canyon, Santa Rita Mountains, August-Dec ember, 1955.--- 2?
8. Morning versus evening feeding habits by percentage of browse, forbs and grasses taken, Florida Canyon, Santa Rita Mountains, 1955-1956.------27
9. Upper versus lower range differences in feeding habits in percentage of browse, forbs and grasses taken, August - October, 1955.---- 28
10. Contents of twelve stomachs collected near the junction of the desert-shrub and oak-woodland associations, November 1954 and November 1955•-----— ----- — ------— ------30
11. Contents of fourteen stomachs collected near the junction of the desert-grassland and oak-woodland or pinyon-juniper associations, November 1955.------31
12. Contents of two stomachs collected in the yellow pine association,- November 1955.------32
13. Volumetric analysis of seventeen stomachs collected in November 1955.------33 Number Page
14• Summary of use and growth of plants located in browse transects in the Chiricahua Mountains (8,000 - 9,000 ft.) 1955.------45
15. Summary of utilization and net gain or loss to plants from browse transects in Canelo Hills (5,000 ft.).------45
16. Acorn count on oak transects, 8,000 to 8,500 feet, Chiricahua Mountains, September 1954 and September 1955.------46
17. Plant composition of Antler Park, Chiricahua Mountains, September 1954.------50
18. Results of ovary analysis from does taken in the Chiricahua Mountains, November 1955.------55
19. Buck-doe ratios, Chiricahua and Santa Rita Mountains, August-Dec ember 1955, inclusive.------56
20. Doe-fawn ratio in the Chiricahua and Santa Rita Mountains, September-December 1955, inclusive.— ------56 LIST OF FIGURES
Number . Page
1. Bar Foot Park area, Chiricahua Mts. January 1956.------:— 5
2 . Foothills on western slope of the Chiricahua Mts. January 1956.------B
3. Scene from Rustler Park road, Chiricahua Mts. looking eastward into New Mexico. January 1956.------9
4* Juniper encroachment over grassland Pinery Canyon, Chiricahua Mts. January 1956.------— — — 10
5. Single plant of Mimosa dysocarpa. Santa Rita Mbs. January 1956.------19
6. False mesquite (Calliandra eriophylla). Santa Rita Mts. January 1956.------20
7. Heavily browsed deerbrush (Ceanothus Fendleri). Bar Foot Park.Chiricahua Mts. January 1956.------26
8 . Heavily browsed mountain mahogany (Cercocarpus betuloides). Bar Foot Park, Chiricahua Mts. January 1956.------37
9. Heavily browsed young juniper (Juniperus Deppeana) January 1956.------:------— 39
10. Ocean spray plant (Holodiscus dumosus). Rustler Park, Chiricahua Mbs. January 1956.------40
11. Heavily browsed ponderosa pine. Rustler Park, Chiricahua Mts. January 1956.------41
12. Heavily browsed silverleaf oak (Quercus hypoleucoides). Bar Foot Park. January 1956.------42
13. Heavily browsed white fir (Abies concolor). Rustler Park, Chiricahua Mts. January 1956*------43
14. Heavily browsed mock orange (Philadelphus microphyllus). Rustler Park Road, Chiricahua Mts. January 1956.------44
15. Heavily browsed silk tassel (Garrya Wrightii). Pinery Canyon. Chiricahua Mts. January 1956.--- -— ------52 ACKNOWLEDGEMENTS
I wish to express my appreciation to the Arizona Cooperative
Wildlife Research Unit for making available to me the fellowship
which enabled me to carry out this project.
I wish also to extend my sincerest thanks to Dr. Lyle K. Sowls,
Leader of the Arizona Cooperative Wildlife Research Unit, for his help
and encouragement and his valuable assistance in preparing and editing
the manuscript.
I am indebted to Charles R. Hungerford, Assistant Leader of the
Arizona Cooperative Wildlife Research Unit, who was always ready to
come into the field and assist me in any way possible*
Thanks are also due the following members of the university
faculty: Dr. E. Lendell Cockrum, assistant professor of zoology for
advice on the taxonomy of the white-tailed deer and criticism of the
manuscript. Dr. Charles M. Mason, assistant professor of botany for
assistance with plant identification and for verification of plant
names. Dr. William J. Pistor, for advice on deer diseases and parasites.
Dr. Robert R. Humphrey for criticism of the manuscript.
To Mr. John W. Bohning, Range Conservationist, United States
Forest Service, I extend my thanks for his many kindnesses.
This study was financed by the Arizona Cooperative Wildlife
Research Unit, which is cooperatively maintained by the following
organizationsi The University of Arizona, The Arizona Game and Fish
Department, The United States Fish and Wildlife Service and The
Wildlife Management Institute. Chapter I
INTRODUCTION
The present range of the white-tailed deer (Odocoileus virginianus couesi) in Arizona contains areas which appear to be similar in vegetative and topographical features, but the deer populations supported by these units differ greatly.
The white-tailed deer ranges in Arizona usually consist of isolated units such as the higher desert mountain ranges in the
southeastern part of the state. Some of the areas have relatively high deer populations while others have very low deer populations.
We need to maintain populations of healthy deer on these ranges
and insure continued health of the herd and the range by keeping
the herd within the limits of the food supply. A knowledge of
food habits, range conditions, and reproductive rates were
considered as basic steps to accomplish this end.
In the fall of 1954 a study of the white-tailed deer and their
ranges in southeastern Arizona was begun. The objectives of this
study were: . (l) to determine the factors limiting the populations
of white-tailed deer in southeastern Arizona, (2) to compare
several deer ranges and determine what constitutes good deer
habitat, (3 ) to determine the carrying capacity of these deer
ranges, and (4 ) to try to find means of diminishing the effects
of the limiting factors and bring about an increase in white-tailed
deer populations.
1 2
Little has been published concerning the plants eaten by the
■white-tailed deer in Arizona. This is especially true of annual plants and unusual foods. A. A. Nichol (1938) conducted a pen-feeding study of whte-tailed deer in the Santa Rita Mountains of southern
Arizona. Nichol conducted palatability tests on 168 native browse, forb, and grass species. The tests showed that shrubs comprised a dependable and substantial part of the deer diet, but that the trees, grasses, weeds, and annuals were also important. From these experiments Nichol concluded that shrubby buckwheat (Eriogonum
Wrightii) was the most important single shrub in the white-tailed deer's diet*
It was not known what specific plants could be used as indicators of deer range conditions in the various vegetative associations. That there was competition for food between cattle and deer has been suspected, but its importance is not known.
Before studies of competition can be made it is first essential to know which plants are eaten by deer. Thus a knowledge of foods eaten by deer will be important to annual appraisals of range condition and as a guide in determining the extent of
deer-livestock competition.
Description of study areas:
Three main study areas were used. They were:
(l) Florida Canyon in the Santa Rita Mountains at about 4,300 feet
elevation. This area is at the place where the desert grassland 3 and oak-woodland vegetative types meet. The site is characterized by
Emory oak (Quercus Emoryi), Mexican blue oak (Quercus obloneifolia). mesquite (Prosopis .iuliflora), cat claw (Acacia Greggii), mimosa
(I4imosa dysocarpa), and false mesquite (Calliandra eriophylla).
Dominant grasses are perennial grama grasses (Bouteloua spp.).
(2) Canelo Ranger Station in the Canelo Hills at 5,000 feet
elevation. This is an open oak-woodland area. Some representative plants are Emory oak (Quercus Emoryi). Mexican blue oak (Quercus
obloneifolia), silk-tassel (Garrya Wrightii), mountain mahogany
(Cercocarpus betuloides), and cliff-rose (Cowania mexicana).
Dominant grasses are perennial grama grasses (Bouteloua spp.).
(3) Bar Foot Park in the Chiricahua Mountains at 8,500 feet
elevation. This area is located in the yellow pine vegetation type.
A fire that occurred about five years ago burned over a portion
of this study site. This area is characterized by yellow pine
(Pinus ponderosa), silverleaf oak (Quercus hypoleucoides) and
netleaf oak (Quercus reticulata). Grasses are represented by
mountain muhly (Muhlenbergia montana) and pine dropseed (Blepharoneuron
tricholepis).
Climate:
The summer climate of this region is controlled by the "thermal
low" found in the desert areas of the southwest. Throughout the
remainder of the year the weather is dominated by the "Pacific high" 4 with an occasional cold frontal passage in the winter. The climate is typified by two rainy seasons and two dry seasons. The summer rains come as heavy showers which originate as thunderstorms, while the winter rains are of the slower, steady frontal type. The average rainfall, most of which falls during the summer, varies from eleven inches in the lower elevations to twenty-seven inches on the mountain peaks (Smith, 1956). Except at the higher elevations, deer are not influenced by snow. The yearly mean temperature varies from 44° to
65° Fahrenheit. The lowest January mean in the high altitudes is
27° Fahrenheit. The highest July mean in the lower elevations is
88° Fahrenheit. Figure 1. Bar Foot Park area, Chiricahua Mts. January 1956. Chapter II
CLASSIFICATION AND DISTRIBUTION OF ARIZONA WHITE-TAILED DEER
The Arizona white-tailed deer was first described in 1875 as
Cariacus virginianus Var. conesi by Cones and Yarrow. Miller and
Kellogg (1955) designate it as Odocoileus virginianus couesi.
(Cones and Yarrow).
A common belief among sportsmen is that there are two separate
races of white-tailed deer in southern Arizona. These they call
the Arizona white-tailed deer and the Mexican fan-tailed deer. Any
deer smaller than average or redder than average hunters usually
call "a fan-tail"•
The opinion of Dr. E. Lendell Cockrum, mammalogist. University
of Arizona, expressed in a verbal conversation, is that southern
Arizona is the northern limit of the intergradation belt between
the sub-species Odocoileus virginianus couesi and Odocoileus
virginianus sinaloae. Therefore, all white-tailed deer in Arizona
should probably be called Odocoileus virginianus couesi. Individual
deer may display some Odocoileus virginianus sinaloae characteristics,
but they conform more closely to Odocoileus virginianus couesi
standards.
The Arizona white-tailed deer has two pelages, a red summer
coat and a blue-gray winter coat. During this study gray does
were seen with gray fawns, gray does with red fawns, red does with
gray fawns and red does with red fawns. Of about 1,500 white-tailed
deer seen during the study all appeared to be Odocoileus virginianus couesi.
6 7
In Arizona the white-tailed, deer is generally restricted to the southeastern desert mountain ranges. The western edge of their range in Arizona follows roughly the eastern border of the Organ
Pipe National Monument northward to the Mogollon Rim. The northern limit follows the face of the rim. The white-tailed deer range extends into Mexico and New Mexico. Some of the better white-tailed deer areas include the Chiricahua, Huachuca and Santa Rita Mountains and the Canelo Hills.
As to the total area covered by Qdocoileus virginianus couesi. the following is quoted from Miller and Kellogg (1955):
"Mountain regions, especially steeper slopes, .from Colorado River (Ehrenberg) and Mogollon Mesa in southern Arizona and southwestern New Mexico (Datil Mountains, west of Rio Grande Valley) south along Sierra Madre through central and eastern Sonora (west to Cobota and Pozo de luis), western Chihuahua, northern Sinaloa, Durango, northeastern Zacatecas (Plateado), and northern Jalisco (near Bolanos)."
The deer in the individual mountain ranges are as isolated as
if they were on islands. The ranges are surrounded by miles of desert
or high-desert grasslands. There are areas where some interchange
is possible. The Santa Rita and Patagonia Mountains are linked to
the Huachuca Mountains by a low rolling formation known as the
Canelo Hills which offers a possible avenue of travel. Other
opportunities for interchange exist between the Santa Catalina
and Rincon Mountains and between the Chiricahua and Dos Cabezas Mountains. 8
x
Figure 2. Foothills on western slope of the Chiricahua Mbs. January 1956. 9
Figure 3. Scene from Rustler Park road, Chiricahua Mts. looking eastward into New Mexico. January 1956. Figure 4. Juniper encroachment over grassland Pinery Canyon, Chiricahua Mbs. January 1956. 11
Altitudinal distribution:
Arizona white-tailed deer have a wide elevational distribution.
The species occurs from the 3* 500-foot level up through and including areas above the 10,000-foot level. The lower elevations generally produce the highest populations although at high elevations in some mountain ranges herds of deer occur. The existence of deer populations
in the high altitudes seems to depend upon the topography. In the
high areas topography is apparently a limiting factor. Where mountains
are comparatively broad-topped, such as the Chiricahua Mountains,
deer are usually numerous. Where mountains have narrow, steep tops,
such as the Santa Rita Mountains, only a few deer are found at the
higher elevations.
Microclimates caused by direction of slope are of importance
in that a wide variety of plants is available at any one altitude.
Distribution by plant associations:
In Arizona the white-tailed deer have a wide variation of
habitat. They are found from the edge of the desert-grassland
association, upward through the oak-woodland, pinyon-juhiper,
yellow pine and spruce-fir associations.
Deer numbers can be correlated with plant associations as
described by Nichol (1937):
Southern desert-shrub association. The white-tailed deer are
generally not found in this association. 12
Desert-grassland association. Deer are not abundant in this association along its upper boundaries.
Oak-woodland association. Open oak-woodlands are well populated although there is a general decrease in deer numbers with increasing density of the flora. The edges of the dense areas are valuable for cover. .
Pinyon-.juniper association. White-tailed deer are numerous throughout this association, but dense vegetation can.limit the size of the population. Protection offered by the edges of the dense areas is of value*
Yellow pine association. A pm* yellow pine stand is not good white-tailed deer rangej however, in areas of old b u m s and open ridges where browse species flourish, deer can be found in fair numbers* , . .
Spruce-fir association* Some deer are found in this association but generally desirable food plants are few and deer are scarce except on the edges of the clearings. Optimum conditions apparently exist at the junction of the desert-grasslands with either the oak-woodland or the pinyon-juniper types. Chapter III
ANALYSIS OF FEEDING HABITS
Under existing conditions in Arizona some of the more commonly practiced methods of obtaining food-habit data, such as stomach analyses and pen studies, are inadequate. During this study the gathering of stomach samples was almost entirely restricted to the hunting season.
To persuade a hunter to collect.a stomach sample was difficult, and many of the sample s collected by hunters contained only a fraction of the amount needed for a reliable analysis. Road and illegal kills were not numerous.enough to add many samples. Under these circumstances,
stomach analyses alone are not adequate for a food-habits study.
In Arizona practically all white-tailed range is also cattle
range. The value of vegetative "use transects” was limited by the
absence of cattle and cattle-deer exclosures. It is nearly impossible
to determine the percentage of the total vegetation utilized by deer
or by cattle. Some types of utilization on browse species by deer is
difficult to detect by "use-transects”. For example during August
browsing on leguminous shrubs consisted of stripping the leaflets
from the individual rachis of the compound leaf. This browsing was
difficult to detect on the transects but was clearly demonstrated
by the feeding-minute method. The feeding-minute technique was
adopted and found to be a valuable method in this particular
food-habits study.
13 14
The fee&mg-minute technique:
The feeding minute as used in this paper is to mean one minute of feeding by an animal unit.
In the 1920*3 and 1930‘s the feeding-minute method was used by
the Soil Conservation Service on cattle and sheep range in some of the western states. Joseph S. Dixon (1934) made an early application of
the method in the wildlife field in his work on mule deer in California.
Buechner (1950) used this technique to study the foods taken by
antelope in the Trans-Pecos area of Texas. In all of these studies
the method was considered reliable and workable by the investigator•
Methods:
The time spent by a deer feeding on a particular plant was gathered
both from horseback and on foot. Most observations were made from
distances of ten to one-hundred and fifty yards. With good reference
markers, such as readily distinguishable rocks, trees or shrubs,
accurate observations have been made from distances up to one—quarter
of a mile. Although most observations fell within these limits
measured on a straight line of sight, the walking distance down one
side of a canyon and up the other to identify the plant was usually
much longer. A record of the time spent by a deer feeding on each
species was kept as well as a catalog of the number of plant contacts,
a plant contact being an animal unit feeding on a single plant for an
unspecified length of time. In this study, feeding time was recorded 15 to the nearest five seconds. From the point of observation, the plant from which a deer was feeding was not always visible but it was not difficult to find when the general area was properly located.
When several contacts were being made at the same time a small sketch map helped greatly in finding the exact areas of the contacts.
The only equipment required to make timed observations was a pair of binoculars and a stop watch or an ordinary watch with a
second hand. A twenty-power spotting scope was used early in the
study but because of the steep topography and dense vegetation it
proved to be a hindrance rather than a help. A pair of 7x35 binoculars
was found adequate for the job. A working knowledge of the flora
of the area and help from a herbarium and from professional botanists
were indispensible.
Advantages of technique:
The deer had a wide choice of foods during a year’s time
because of elevational distribution of the deer and by two dry and
two wet seasons. In the author's opinion, the most successful way
to cover such a combination of possibilities is by the feeding-minute
method. The observer's own desire to have the results of a maximum
number of observations prompted Jii® to be where the most feeding
time was available. When the deer moved to a new area the observer
would soon follow.
Differences, if any, in the feeding habits of the sexes, or age 16 groups, or differences in elevational or geographical feeding habits can be discerned by this technique.
Disadvantages of technique:
There were certain drawbacks and limitations to the feeding-minutes technique. Some of the more obvious were: (l) It takes different amounts of time to consume equal volumes of different plants.
(2) Plant species that deer can be noted browsing are limited to the species existing on the areas studied. (3) It is nearly impossible to obtain data in thick brushy areas. (4) Night feeding-time data can not be gathered. (5) Consumption of grass by deer was hard to detect and even harder to evaluate.
In southern Arizona the areas of dense chaparral are not as productive for deer forage species as the more open areas. If the findings of Biswell g£ al .(1952) regarding California chamise chaparral apply to other western chaparral areas, only a minor portion of the feeding takes place in the dense areas. Most forage
species found in the dense growth were also found in a more accessible
location in the open. Observations indicate that in Arizona, white
tailed deer preferred at least partially open areas for feeding.
Results of feeding-minute method:
During thd study a weather observation consisting of wind direction
and velocity, amount of sky cover, type of clouds, and other weather 17 phenomena were recorded for each trip in the field. The only element
that appeared to adversely affect feeding was high wind. With winds
of more than forty miles per hour the deer nearly always took shelter
in the ravine bottoms. Deer have been observed feeding during rain
and thunderstorms as long as the wind remained relatively low.
Tables 1 through 5 give the data gathered from observing feeding
deer. These tables show the plant species eaten, the number of
observations, and total feeding time observed on each species. Plants
were assigned different classes of availability and abundance, based
on field observations by the author. The listings are for the study
areas only and are not necessarily representative of the entire
mountain ranges.
In the low altitude ranges, leguminous browse plants were the
most important forage. During the summer months Mimosa dysocarpa
(figure 5) was the most important browse plant. Im October the deer
began eating Calliandra eriophylla (figure 6 ) frequently and by
December the plant had become the major item of diet. During the
winter months the deer were often found on the open south-facing
slopes. Calliandra eriophylla and to a lesser extent Krameria parvifolia
grew on these slopes and were extensively eaten by deer. This heavy
use of legumes is probably an important cause of cattle-deer competition
in this area. Forbs were of minor importance even though 1955 was
an exceptional year for their production. 18
The fruit of barrel cactus (Ferocactus Wislizeni) was eaten by deer* Deer ate one.or two fruits from a plant but then,ignored the species for the rest of the feeding period. A relatively large number of contacts was made on the plant species but the total feeding time was low.
Some plants were fed upon by deer only for short periods, but were then heavily used. Such plants may be important to deer though they were not eaten during a long period. In most parts of the West 0 and North, winter is the most critical time of the year for deer, but in southern Arizona this is not true. Here late May, June, and the first half of July is apparently the most critical time of food shortage for the Arizona white-tailed deer. This is the driest time of the year in southern.Arizona and green forage is scarce. With the coming of summer rains in July the new growth starts, but most plants do not react rapidly enough to furnish immediate green forage.
A common plant in the lower elevations is ocotillo (Fouquieria
splendens). This plant produces foliage quickly following the first
rains. These leaves were heavily eaten by deer for a short period
of time. In 1955 the first rains came on July 12, and July 13. Up
to this time the ocotillo was completely devoid of foliage. By the
week of July 15 - 21, however,, it was taken during 86 per cent of the
observed feeding time. In August of that year it was taken only
. 2 per cent of time and in September it was dot observed to be taken 19
Figure 5* Single plant of Mimosa dysocarpa. Santa Rita Mts. January 1956* \ s
20
Figure 6. False mesquite (Calliandra eriophylla). Santa Rita Mts. January I95ST Table 1. Use of non-leguminous browse species in the low-altitude study areas (4,000 - 5,500 ft.) June 15, 1955 - February 1, 1956
X Total time Total Availability Abundance Plant ;• Minisecv Contacts Seasonal All year High Medium Low
Fouquieria splendens 85:20 58 X X Eriogonum Wrightii 27:25 14 X X Ferocactus Wislizeni 11:50 24 X X Celtis pallida 7:40 4 X X Garrya Wrightii 7:35 3 X X Cercocarpus betuloides 6:30 8 X X Quercus oblongifolia 4:30 3 X X Brickellia sp*. 2:40 3 X X Opuntia spinosior 2:05 4 X X Juniperus Deppeana :50 2 X X Lonicera sp. :35 1 X X Ceanothus Greggii :30 1 X X Quercus Emoryi :25 1 X X
157:55 126 Table 2« Use of leguminous browse species in the low altitude study areas (4,000-5,500 ft.) June 15, 1955 - February 1, 1956
Total time Total Availability Abundance Plant . Min:sec. Contacts Seasonal All year High Medium Low
Calliandra eriophylla 1177:45 267 X X Mimosa dysocarpa 644:20 322 X X Krameria parvifolia 256:50 87 X X Mysenhardtia polystachya 72:55 28 X X Prosopis juliflora 36:20 28 X X GalliandrA humili s 33:10 6 X X Acacia angustissima 7:10 5 XX Acacia Greggii 3:55 6 X X Acacia constricta 2:05 1 X X Dalea sp. :40 1 X X - 2235:10 751 Table 3» Use of forbs and grasses in the low altitude study areas (4,000 - 5,500 ft.) June 15, 1955 - February 1, 1956
Total time Total Availability Abundance Plant______Min:sec._____ Contacts Seasonal All Year_____High Medium Low
Ipomoea longifolia 68:15 29 X X Bouteloua spp. 42:45 13 XX Cassia leptadenia 38:35 10 X X Ipomoea barbatisepala 26:15 9 XX Franseria sp. 7:35 3 X X Eriochloa sp. 5:15 2 X X Ambrosia sp. 4:50 4 XX Desmodium sp. 4:35 7 X X Paspalum distichum 4:00 1 X X Portulaca coronata 2:45 3 XX Euphorbia heterophylla 2:35 3 X X Mentzelia asperula 2:20 3 X X Oxybaphus coccineus 1:15 2 X X Aspicarpa hirtella 1:15 1 XX Xanthium sp. 1:00 2 X X Trifolium sp. 1:00 1 X X Anoda cristata :50 1 XX Carex sp. :40 2 X X 215:45 96 Table 4 . Use of browse species in the high altitude study area (8,000 - 9,000 ft.) July 1 - December 1, 1955
Total time Total Availability Abundance Plant . Min:sec. Contacts Seasonal All Year High Medium Low
Ceanothus Fendleri 93:55 23 X X Quercus hypoleucoides 8:35 5 X X Quercus Gambelii ___ ^ 0 1 X X 103:00 29
Table 5. Use of forb and grass species in the high altitude study area (8,000 - 9,000 ft.) July 1 - December 1, 1956
Total time Total Availability Abundance Plant Min:sec. Contacts Seasonal All Year High Medium Low
Delphinium adesicola 221:45 41 X X Agoseris sp. 95:05 26 X X Lupinus Blumeri 55:55 29 X X Solidago sp. 30:25 14 X X Muhlenbergia montana 10:50 3 X X Unidentified forb 7:10 4 X X Amaranthus Powellii 7:10 3 X X Achillea lanulosa 6:40 2 X X Senecio Biglovii 2:10 3 X X Car ex sp. 1:05 1 X X 438:15 125 25 at all* The sudden rise and sharp drop of feeding time on ocotillo is shorn in Table 6 .
Forbs appeared to be more important in the high altitude ranges than in the low country. Possibly they are greener for a longer period at the higher elevations and thus remain palatable longer. By the first' frost, the deer had stripped all of the leaves from the tall larkspur (Delphinium andesicola). Ceanothus Fendleri (figure 7) was an important browse plant in the higher elevations and served as a range condition indicator.
Table 6 . Per cent of total observed feeding time spent on browsing of Fouquieria splendens and rainfall record for Florida Canyon, Santa Rita Mountains, 1955•
Percentage Total time in area Rainfall Date______of use______. Min:sec______.00 inches
June 17-23 0 22:25 .00
June 24-30 0 22:20 .00
July 1-7 0 20:00 .00
July 8-14 Not in this study area .60
July 15-21 86 51:50 1.21
July 22-28 44 92:45 1.81
July 29-August 4 Not in this study area 1.24
August 5 - H 4 85:10 3.36
August 12-18 2 64:30 2.01
August 19-25 0 11:10 4.59 Figure 7* Heavily browsed deerbrush (Ceanothus Fendleri). Bar Foot Park. Chiricahua Mts. January 1956. 27
No significant difference in feeding habits of bucks, does, or fawns were noted.
In the lower elevations there is a tendency toward higher forb
consumption in the early morning hours than in late evening. The
forbs are apparently more succulent in the early morning during the
period of highest relative humidity.
Table 7,. Percentage of total feeding time on browse, forbs and
F t * » * O - V * UU
Total-time Deer class Browse Forbs Grasses Min:sec.
Bucks 89 9 2 425:50
Does 94 4 2 863:30
Fawns 98 2 0 256:15
Unclassified 96 4 0 151:05
Table 8 . Morning versus evening feeding habits by percentage of browse, forbs and grasses taken, Florida Canyon, Santa Rita Mountains, 1955-1956.
Morning______Evening
Month Percentage Use Percentage Use
Browse Forbs Grasses Total time Browse Forbs Grasses Total time . Min:sec . Min:sec
July 100 0 0 14:10 100 0 0 140:05
August 87 6 7 117:05 96 2 3 91:25
September 34 59 7 77:30 60 40 0 60:25
October 94 0 6 292:25 100 0 0 97:10
November 98 2 0 246:40 100 0 0 136:10
December 100 0 0 356:25 100 0 0 219:25
January 100 0 0 344:55 100 0 0 108:10 28
The use of forbs in the higher elevations constituted a larger percentage of the total feeding time and extended over more days than in the lower ranges. Table 9 summarizes the percentage of browse, forbs and grasses used in a lower and in an upper range.
Table 9 ). Upper versus lower range differences in feeding habits in percentage of browse, forbs and grasses taken, August-October 1955.
Santa Rita Mountaina A,300 ft. Chiricahua Mountains 8*500 ft.
Month______Percentage Use______Percentage Use______
Browse Forbs Grasses Total time Browse Forbs Grasses Total time ...... Min:sec ____■ ______Min:sec
August 91 4 5 208:30 79 21 0 80:25
September 45 51 4 139:55 8 87 5 208:15
October 97 0 3 389:35 9 91 0 240:05
Summary of feeding-minute technique:
(1) There were two reasons for the success of the feeding- minute technique in Arizona. They were: (a) on most of the range
the plant spacing was such that location of the browsed plants upon
which feeding minutes were obtained was possible, (b) low relative
humidities made fresh clippings easily distinguishable from prior
ones because the clipped ends dried rapidly.
(2) In the lower elevations, deer range conditions could be
determined by studying the condition of leguminous browse plants of
the genera Calliandra. Mimosa and Krameria. 29
(3) Forbs were of greater importance in the high altitudes.
This probably reflected their longer period of availability at the
higher elevations.
(4) There was no significant difference in feeding habits of
bucks, does and fawns.
(5) The deer consumed more forbs in the early morning than
in the late evening hours.
Collection and analysis of stomach samples:
During the course of the study a total of twenty-eight deer
stomachs were collected and analyzed* These consisted of stomachs
from nineteen bucks, six does and three fawns. Fourteen of the
samples were obtained from the Chiricahua Mountains, eight from
the Santa Rita Mountains, three from the Canelo Hills, two from
the Patagonia Mountains and one from the Ruby Mountains.
The samples were collected in two-quart plastic freezer bags
that had been distributed to the hunters. After collection the
samples were placed in loose woven cotton gauze and washed under a
tap or in a creek. They were then placed on paper towels to dry
and later stored in ordinary grocery bags until analyzed.
Collection of stomach samples by hunters was not a productive
means of acquiring the material. Of the twenty-eight samples
collected, eighteen were turned in by personal acquaintances.
Data from the analysis of stomach contents collected is summarized
in tables 10, 11, 12 and 13. 30
Table 10. Contents of twelve stomachs collected near the junction of the desert-shrub and oak-woodland associations. November 1954 & November 1955
Plant Part taken Times occurring
Aristida sp. foliage 1
Bouteloua spp. foliage 5
Calliandra eriophylla foliage 11
Celtis pallida foliage 5
Cercocarpus betuloides foliage 1
Cowania mexicana foliage 1
Eysenhardtia polystachya foliage 4
Ferocactus Wislizeni fruit 5
Helianthus sp. foliage 1
Juniperus Deppeana foliage 2
fruit ■ 1
Mimosoideae species foliage 1
Opuntia sp. fruit 1
Prosopis juliflora foliage 1
beans 3
Quercus spp* foliage 1
Rhus trilobata foliage 1
Solanum sp. fruit 1
Yucca sp. fruit 1 31
Table 11. Contents of fourteen stomachs collected near the junction of the desert-grassland and oak-woodland or pinyon—juniper associations, Movenber 1955.______
Plant Part taken Times occurring
Arctostaphylus sp. foliage 1
Calliandra eriophylla foliage 1
Cenchrus sp. seed 1
Cercocarpus betuloides foliage 5
Cucurbitaceae species fruit 1
Fallugia paradoxa foliage 2
Garrya sp. foliage 2
Gramineae spp. foliage 2
Juniperus Deppeana foliage 9
berries 5
Leguminosae sp. foliage 1
Pinus cembroides foliage 1
Phoradendron sp. foliage 5
Quercus spp. foliage 9
acorns 4
Salix sp. foliage 2
Vitis sp. foliage 1
Yucca sp. fruit 1 32
Table 12. Contents of two stomachs collected in the yellow pine association, November 1955.
Plant Part taken Times occurring
Abies concolor foliage 1
Agoseris sp. foliage 1
Gramineae sp. foliage 1
Pinus ponderosa foliage 1
Quercus spp. foliage 2
Salvia sp. foliage 2
From the preceding tables it can be seen that grasses occurred in eight of the samples. This was a much higher percentage of use than that indicated by the feeding minute method. However, it was believed that some of the grasses in the stomach samples were picked up accidentally while the deer were feeding on other low growing plants. In most cases only a few grass fragments were present in each sample.
Volumetric analysis of stomach samples did not give worthy
results because of the small number of stomachs collected. Of
the seventeen samples analyzed by volume, only one contained
Vitis sp. yet it gave a larger volume than all of the other
articles combined.
The identifiable plant parts were separated in the dry state,
moistened and then placed in a graduate cylinder containing water.
The amount of water displacement was then taken as the total
volume of the plant. 33
Table 13. Volumetric analysis of seventeen stomachs collected in November 1955.______T=trace.______
Plant Times occurring Volume-c.c.
Abies concolor 1 1
Agoseris sp. 1 1
Arctostaphylos sp. 1 T
Calliandra eriophylla 3 T
Cenchrus sp. 1 T
Cercocarpus betuloides 5 5
Cucurbitaceae species 1 3
Bysenhardtia polystachya 1 T
Fallugia paradoxa 2 7
Garrya sp. 2 3
Gramineae spp. 5 T
Juniperus Deppeana (foliage) 7 10
(berries) 6 7
Leguminosae species 1 T
Phoradendron sp. 5 4
Pinus cembroides 1 T
Quercus spp. (foliage) 10 12
(acorns) 4 T
Salix sp. 2 3
Salvia sp. 2 1
Vitis sp. 1 83
Yucca sp. 2 1 34
Table 13 is a summary of the seventeen stomachs analyzed by volume. The majority of the stomachs came from the Chiricahua
Mountains* Chapter IV
ANALYSIS OF RANGE CONDITION
A most important consideration in big game management is the continued production of desirable forage. After the desirable plants are determined it is important to control the deer herd numbers so that adequate production of their food plants is guaran teed. Management of the big game herds thus becomes primarily a problem of holding the herd well within the carrying capacity of the range. Therefore range condition studies are of first importance to a practical management program.
A determination of degree of use of some of the important browse species is an important step in arriving at deer range con
dition, By computing degree of utilization of browse species it can
be determined whether the size of the deer herd is within the carrying
capacity of the range. For these purposes many standard range manage
ment procedures are available. Others must be modified to fit the
needs of game management.
Browse transects:
One of the most important techniques for evaluating range condition
for both big game and livestock is the establishment of permanent browse
transects. During this study browse transects were placed in two
areas, (1) near the Black Oak Cemetery in the Canelo Hills and (2) in
the vicinity of Bar Foot Park in the Chiricahua Mountains,
35 36
The transects were one hundred feet in length. The shrubs were described as "so many feet left or right of the tape". Four branches were tagged on each plant. Metal tags, wire loops and numbered plastic bird bands were used as twig markers. The plastic bird bands were the most satisfactory markers. Since they were brightly colored, yellow, red, green and blue, they were easy to locate. One of the advantages of the bands was that they would increase in size as the diameter of the twig increased, instead of cutting into the cambium as wire does.
Unfortunately there were no cattle and deer exclosures available so reliable average growth figures could not be obtained. Percentage of use figures are based on the growth average of all twigs showing any increase over the original measurement.
Above the 8,000 foot level in the Chiricahua Mountains, mountain mahogany (Cercocarpus betuloides). (figure 8 ) was in poor condition.
The plants were high-lined and there appeared to be no reproduction.
In September 1954# a transect was placed near Bar Foot Park in an
area excluding cattle by the steepness of the slope. The transect
was re-examined in July 1955. These measurements indicated
100 per cent use of the current average annual growth plus an
additional 62 per cent use of older growth. In this ten-month
period there was a net loss to the 20 tagged stems of 12s inches.
Stems as large as one-quarter of an inch had been nipped off.
All other transects were placed in August 1955, and re-examined
January 1956. As indicated by Swank et §1.(1954) this placement 37
Figure 8. Heavily browsed mountain mahogany (Cercocarpus betuloides), Bar Foot Park, Chiricahua Mts. January 1956# 38
date in August comes after the greatest growth period for most Arizona
browse species* Nevertheless it was felt that the figures were pertinent
in that heavy browsihg of Cercocarpus betuloides was found in the high
altitudes during late fall and winter. Use of mountain mahogany was
noted earlier in the fall at the 5*000 foot level than at the 8,000
foot level. This was probably because forbs at the higher elevations
appeared to remain palatable longer than those in the lower areas.
The Ceanothus Fendleri plants were in a precarious state as indicated
by a net loss to the plants for the period covered. The plants were
all of low stature and badly hedged. They were continually browsed
from above as well as from the sides and their vigor was probably
very low. Under present browsing pressure it is only a matter of time
until they will be eliminated or rendered useless. Other plants
listed on which severe browsing has been noted are shown in figures
9, 10, 11, 12, 13 and 14.
Table 14 is a summary of the browse measurements in the
Chiricahua Mountains and table 15 is a summary of measurements from
the Canelo Hills.
Index for acorn production:
In Arizona the annual acorn crop is important to deer and turkeys.
Uhlig and Wilson (1952) and Moody et al.(1954) described methods to
accurately measure the mast crop. The measurement was accomplished
by placing catch boxes under some of the trees and relating the catch
to the entire area.
. Figure 9. Heavily browsed young juniper (Juniperus Deppeana) January 1956# Figure 10* Ocean spray plant (Holodiscus dumosus). Rustler Park, Chiricahua Mts. January 1956. 41
Figure 11. Heavily browsed ponderosa pine. Rustler Park, Chiricahua Mts. January 1956. Figure 12. Heavily browsed silverleaf oak (Uuercus hypoleucoides). Bar Foot Park. January 1956. 43
> f
Figure 13# Heavily browsed white fir (Abies concolor)• Rustler Park, Chiricahua Mts, January 1956
i
l I 44
' ■ m
‘J&'-r H i 45
Table l^. Summary of use and growth of plants located in browse transects in the Chiricahua Mountains (8.000 to 9,000 ft.) 1955.
Number Average Percentage use Total net of Growth of available Gain or Loss, Plant Stems 8/55 to 1/56 browse Ten plant basis
Ceanothus Fendleri 39 ►5 inches 1192 - .9 inches
Quercus reticulata 12 1 .1 85 +1.7
Quercus hypoleucoides 20 .9 52 +4.3
Cercocarpus betuloides 128 1.4 40 +9.0
Philadelphus microphyllus* 92 1.3 37 +7.6
Holodiscus dumosus* 44 1.9 5 +7.5
Ribes pinetorum* 4 1.3 0 +13.0
Abies concolor 4 .7 0 +7.5
^Correction made for natural defoliation.
Table 15. Summary of utilization and net gain or loss to plants from browse transects in Canelo Hills (5.000 feet).
Number Average Percentage use Total net of Growth of available Gain or Loss, Plant Stems 8/55 to 1/56 browse Ten plant basis
Cercocarpus betuloides 48 .7 inches 1232 -1 .8 inches
Mimosa dysocarpa* 78 2 .0 47 +10.7
Cov/ania mexicana 72 1.7 25 +12.7
Ceanothus Greggii 20 .5 20 +3.8
^Correction made for natural defoliation 46
Those methods are time consuming and may involve more time than the average game manager can spend on them. A less accurate but faster method of indicating the trends in mast production were attempted on a small, test basis in this study.
The system consisted of laying out line transects and tagging the tree branches. Transects were laid out in two-hundred-foot lengths.
Individual trees were properly located on the transect and a branch was selected at random from each tree and marked with a metal tag. All of the acorns from the tag outward were counted. The transects were re-examined as nearly to the same date as possible each year during the late summer while the crop was maturing. After the original transect placement only the yearly counting of the maturing acorn crop would be necessary.
Table 16' gives the results of one year's measurement by this transect method. The results are not significant because of the small, sample but are included to demonstrate the possibilities of the technique.
Table l6 . Acorn count on oak transects, 8,000 to 8,500 feet, Chiricahua Mountains, September 1954 and September 1955.
Total no. acorns Total no. acorns Plant . September 1954 September 1955
Quercus Gamhelii 172 16
Quercus hypoleuc oide s 0 26
Quercus reticulata 176 164 47
Comparison of deer ranges by pace-transect and pellet-group counts:
Deer-pellet-group counts to determine the degree of range use have been made by McCain (1948) and Julander (1955)•
In this study two test counts were made, one in the summer at the study area in the Canelo Hills and another in the winter at the Santa
Rita Mountain study area. Pace transects were examined on the contours of hill slopes. Pellet groups of all ages were counted if they were within a yard on either side of the transect line. The length of the transects were then multiplied by six to indicate the number of square feet observed.
The transect in the Canelo Hills showed 15 pellet groups per acre while the transect in the Santa Rita Mountains gave 108 pellet groups per acre. Julander (1955) considered two hundred or more groups per
acre to indicate heavy use by mule deer in Utah.
Further study is needed before we can say how many pellet groups
indicate heavy use under conditions prevailing in southern Arizona.
The 108 groups per acre found in the Santa Rita Mountains might
indicate moderate or heavy use while the same figure in the high
altitude ranges would probably indicate over-use. Considering the forage
available in the two areas, the use by deer might be estimated as
moderate for the Canelo Hills and heavy for the Santa Rita Mountains.
Salts and minerals:
Southern Arizona is nearly devoid of natural salt licks. Since
deer thrived in this area long before man and salt blocks arrived. 48 it can be assumed that salt is not an essential item. There is no doubt that deer acquire a taste for salt. In areas where salt has been placed for cattle, white-tailed deer were observed eating the ground out from under the blocks. Less direct use is made of the salt blocks themselves. During 1955 a boy scout troop placed a quantity of salt around Rustler's and Bar Foot Parks for the deer.
Again the deer mainly utilized the dirt under the salt, making holes more than a foot square.
In other western states mineral selectioh experiments have been
conducted to point out range deficiencies. Following the general method of Stockstad et al. (1953) and Smith (1954) mineral cafeterias
were placed near the Sunnyside area on the west side of the Huachuca
Mountains in 1954 and again in 1955• Both tests were lost, once when
rain flooded the containers and again in 1955 when the containers were
trampled by horses. In the same area, yard-square ground-plots were
laid out and mineral solutions poured into then. The test became
invalid when army units from Fort Huachuca extended their operations
to the west side of the mountain range and constructed a road across
the test area.
Importance of open water:
During this study it was found that white-tailed deer concentrations
were located near available water. During the warm months they probably
need drinking water every day and may take it nearly as often during
the rest of the year. 49
White-tailed deer in southern Arizona drink from stock watering troughs as well as from streams and ponds. One of the advantages to deer of dual-use range is that stock tanks constructed for cattle are numerous and are good sources of water.
Lack of water is probably not a major limiting factor over most of the lower range. It may be a limiting factor in some of the higher, more inaccessible areas.
Dense chaparral:
Dense chaparral is a deterent to high deer populations. Biswell
et al. (1952) showed that in dense California chamise chaparral there
was a comparatively low deer population and that the deer present had
a lower reproductive rate than deer in the more open areas.
Chaparral in southern Arizona is increasing. Here lies an
opportunity for habitat improvement. Leopold (1950) recommended use
of controlled burning, chemical plant-poisoning and mechanical brush
cutting to stimulate deer-food production on critical areas not
being used for timber production.
High altitude parks1
Sub-alpine parks or clearings may be necessary for the existence
of white-tailed deer in the high mountain areas. These parks contain
forbs which constitute a large part of the diet of deer for about six
months each year. These forbs are found in sufficient quantity only
in parks and burned over areas. 50
Two fifty-foot descriptive transects were laid out in Antler Park in the Chiricahua Mountains. Table 17 shows the plant composition of the area.
Table 17. Plant composition of Antler Park, ______Chiricahua Mountains. September 1954.
Cover type Percentage
Helianthus sp. 36.0
Lupinus Blumeri 17*7
Litter 17*3
Bare ground 12.9
Gramineae spp. 10.3
Unknown plants 4.8
Castilleja sp. 0.4
Juniperus Deppeana 0.4
Cirsium sp. 0.2
As shown in the feeding-minute section of this paper, blue lupine
(Lupinus Blumeri) is important to the deer. Observation of Bar Foot Park
in the Chiricahua Mountains showed an abundance of this plant and tall
larkspur (Delphinium andesicola). two highly utilized forbs.
Effects of fire on deer range:
In many areas occasional fires were beneficial to deer, interrupting
the ecological process that tends toward closed, homogeneous stands of
trees. The openings encouraged the sprouting of old plants, and the
new growth created an ideal situation for deer. 51
Small chaparral fires cause little or no financial loss and cause only temporary damage if any to the watershed. Controlled fires in these areas would improve the habitat for deer. During this study, burned areas appeared to be more heavily used than utibumed areas of chaparral and ponderosa pine.
Cattle-deer competition:
Of prime interest to the game manager and the cattleman is the
degree of comeptition between big game and livestock. Full-time
studies have been devoted to this subject in many western states.
In Arizona nearly all white-tailed range is also cattle range.
In the section of the state covered by this study there appeared to
be no serious competition between cattle and deer. Competition for
grasses was probably not significant in any portion of the range
studied. Food habits of white-tailed deer in this study and of
mule deer in Utah (Julander, 1955) showed grasses to be of minor
importance. At times competition arose on the use of mountain
mahogany (Cercocarpus spp.) and silk-tassel (Garrya spp.) (figure 15).
The most critical competition arises from the common use of
Calllandra eriophylla and Krameria parvifolia. The importance to
deer of these two plants in the low altitude ranges has been
demonstrated. Cattle are also known to browse these plants heavily.
When overuse of these plants occurs, deer are affected more
seriously than are cattle. These two browse species are diet
staples for deer during much of the year; cattle are not so
dependent upon them. 52
Figure 15. Heavily browsed silk tassel (Garrya Wrightii). Pinery Canyon. Chiricahua Mts. January 1956. I lir' s
i
i Chapter V
PRODUCTIVITY
A correlation exists between the productivity of any deer herd and the condition or health and vigor of the range. Measurement of productivity is highly important to wildlife management. An effort was therefore made in this study to gather as much information as possible relative to the productivity of the deer herd in the
Chiricahua Mountains where most of this study was carried out.
Basic to any productivity study is a knowledge of the breeding season, litter size, behavior of the deer and other details of general life history. During the course of this study details on these phases were gathered whenever an opportunity arose. Efforts were also made to gather productivity data through the collection of reproductive tractb^during the hunting season.
Breeding season:
The breeding season of the Arizona white-tailed deer begins in late December and ends about mid-February. McCabe and Leopold (1951) give the breeding date of Odocoileus virginanus couesi in the Gavilan
River basin. Chihuahua, Mexico as mid-January. The bucks do not
collect large harems but court one or two does at a time. Antlers
are dropped during April and the new growth becomes evident in mid-July. By about the first of October the velvet is rubbed off.
Nichol (1938) gives the average period of gestation as about
53 54
two-hundred days. Fawning begins during early July and is completed
by mid-September. The earliest fawn recorded in this study was on
July 10 in the Canelo Hills. The fawning date of white-tailed deer
in Pennsylvania according to Latham (1950) is late May, June, and
early July. All phases of reproduction for the Arizona white-tailed
deer lag behind the average for the species by about two months.
This difference is generally considered to be an adaption to climate
that brings on fawning during the green months of July, August and early
September. Observations during the course of this study showed single
fawns to be the rule with twins occurring less often. Triplets are
very rare. Theodore Knipe, a game technician who spent many years in
the white-tailed ranges, stated in personal correspondence that he had
never observed triplet fawns. Heavy nursing by fawns lasts two months
with some nursing lasting as long as five months according to Nichol (1938).
After this two-month period of heavy nursing the fawns can survive without
their mother. At the age of two months, the author observed fawns
feeding as regularly, as heavily and on the same plants as the adults.
Analysis of ovaries:
In cooperation with the Arizona Game and Fish Department a total
of thirty-three pairs of ovaries was collected during the 1955
"any-deer" hunt in the Ghiricahua Mountains. The ovaries were fixed in
a ten percent solution of formalin before sectioning. Following the
macroscopic system of Cheatum (1949) the results shown in table 18
were obtained.
A 55
Table 18. Results of ovary analysis from does taken in the Ghiricahua Mountains, November 1955.______
Number of corpora Number of does lutea of pregnancy Average with pigmented Number of present in both ovulation scars of past Age class does in class ovaries rate pregnancy - 0 1 2 3 4
lh 6 6 0 0 0 0 0 .0 0
2| 3 1 2 0 0 0 0.7 0
3 k 7 0 6 1 0 0 1 .1 6
4 s - 6& 8 0 3 3 2 0 1.9 6
7& + 6 0 1 4 0 1 2 .2 5
Unclassified 3 0 2 1 0 0 1.3 2
Totals 33 7 14 9 2 1 1 .2 19
In this study there was little danger of confusing corpora lutea of
ovulation and pregnancy since the last heat period occurred about ten
months prior to the collection. The data are riot conclusive but in
general the trends in ovulation by age groups are similar to those
found by Robinette et al. (1955) for Utah mule deer. There is an
increase in ovulation rate with an increase in age. The average
ovulation rate of does of all ages was 1 .2 as compared to 1 .8 in Utah
mule deer. That there is a significant loss of ova may be indicated by
the presence of more than two corpora lutea of pregnancy in a single
ovary in three of thirty-three cases and the absence of triplets in
the population. The does were aged on basis of tooth development and
wear (Severinghaus, 1949)* Buck:doe and doe:fawn ratios:
During the course of this study all white-tailed deer observed were recorded along with their age and sex where determination was possible. Table 19 gives the observed buck-doe ratio while table 20. gives the observed doe-fawn ratio*
Table 19* Buck-doe ratios, Chiricahua and Santa Rita Mountains, August-Dec ember 19$$, inclusive. ____
Class Chiricahua Mts. Santa Rita Mbs
Bucks 32 62
Does 126 2$7
Ratio-Buck:doe 1:3.9 1:4.2
Table 20. Doe-fawn ratio in the Chiricahua and Santa Rita Mountains, September-December, 19$$, inclusive.______
Class Chiricahua Mts. Santa Rita Mts.
Does 103 183
Fawns 19 97
Ratio-Doe:fawn $:1 2:1
The buck-doe ratio for the two areas is nearly similar and
appears to be typical of herds subject to "buck-only" hunting. The
doe-fawn ratio of five does to one fawn for the Chiricahua Mountains
is low and does not compare with the one to one ratio of does to
fawns noted in mule deer in the Oak Creek-Anderson Mesa area of Arizona during 1951 (Anon., 1954)• However, most of the deer observed in the
Chiricahua Mountains were in the upper elevations where there appeared to be an unusual number of barren does. The low doe-fawn ratio in the
Chiricahua Mountains has several possible explanations; (l) there were not enough deer counted to give an accurate figure, (2) barren does tend to accumulate in these upper elevations through migration, (3) there was little or no elevational migration and does in this area have a low ovulation rate due to poor range conditions, or (4) the fawns were being conceived and lost before birth. Little or no elevational migration was noted during the study. The browse plants in this high elevation range were in poor condition. MacDonald (1952) found that pine needles caused abortion in beef cattle. Could this also be true of deer driven to foraging of pine species? /
58
SUMMARY
(1) In the lower elevations of the desert mountain ranges of southeastern Arizona, deer range condition was evaluated by noting the condition of leguminous browse plants of the genera Calliandra, Mimosa and Krameria.
(2) Middle and high altitude ranges were judged on the condition of Cercocarpus betuloides,
(3) Forbs were found to be of greatest importance in the high altitude ranges, particularly those forbs found in open parks and mountain meadows.
(4) Through the use of. feeding minutes in conjunction with the analysis of available deer stomachs, food habits data was gathered.
(5) The repeated appearance of Juniperus Deppeana and oak foliage
Quercus spp. in the stomach samples, the over-browsing of Cercocarpus betuloides, the heavy browsing of Holodiscus dumosus and Philadelphus microphyllus combined with the low reproductive rate shown by ovarian analysis, all indicated an over-population of deer in the Chiricahua
Mountains during the period of this study►
(6) The single factor most limiting to white-tailed deer populations
in Arizona was found to be range condition. In many areas poor range
condition was brought about by too high a deer population. In some of
the areas studied, poor deer range condition was caused by natural plant
succession, control of fire and heavy dual use of marginal areas by
both deer and cattle. LITERATURE CITED
Anon. 1954. Information supporting recommendations to the commission on 1954 hunting seasons. Arizona Game and Fish Department, Game Management Division publication, Phoenix, Arizona.
Buechner, Helmut K. 1950. Life history, ecology and range use of the pronghorn antelope in Trans-Pecos, Texas. Amer. Midi. Nat., 43:257-354.
Biswell, H. H., R. D. Taber, D. W. Hedrick and A. M. Schultz. 1952. Management of chamise brushlands for game in the north coast region of California. Calif. Fish and Game, 38:453-484.
Cheatum, E, L. 1949. The use of corpora lutea for determining ovulation incidence and variations in the fertility of white-tailed deer. Cornell Veterinarian, XXXUC, No. 3*
Dixon, J. S. 1934. A study of the life history and food habits of mule deer in California. Calif. Fish and Game, 20:181-282, 315-354.
Julander, Odell. 1955. Deer and cattle relations in Utah. Forest Science, 1:130-139.
Latham, Roger M. 1950. Pennsylvania*s deer problem. Penn. Game News, Special Issue No. 1. 48 pp.
Leopold, A. Starker. 1950. Deer in relation to plant succession. Trans. 15th N. Amer. Wildl. Conf.t 571-580.
McCabe, Robert A. and A. Starker Leopold. 1951. Breeding season of the Sonora white-tailed deer. Jour. Wildl. Mgt. 15:433-434.
McCain, Randal. 1948. A method for determining deer range use. Trans. 13th N. Amer. Wildl. Conf.:431-440.
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