Abert Squirrel Burying Pine Cones

Bailey, Florence Merriam

doi:10.1093/jmammal/13.2.165

Cited by 5 publications

(4 citation statements)

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“…However, large caches were not utilized by Abert's squirrels during the course of this study. Abert's squirrels have been observed to singly bury a food item (Bailey 1931, Bailey 1932, Cahalane 1947, and Stephenson (1975) believed this may be a method of caching food. Observations during this study support that idea.…”

Section: Food Cachingmentioning

confidence: 99%

Heterothermy in Free‐Ranging Abert's Squirrels (Sciurus Aberti)

Golightly¹,

Ohmart²

1978

Ecology

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Body temperatures (T_b) of 7 free—ranging Abert's squirrels were monitored by intraperitoneally implanted temperature sensitive radio transmitters. Relationships between Tb, activity, solar exposure, ambient air temperature (T_a), and weather conditions were examined. T_b values ranged from 35.2 to 41.1 degrees C (° = 39.0 degrees C) and varied with behavior. A hyperthermic condition during both summer and winter developed during bouts of intense activity and the degree of hyperthermia was related to intensity of activity. Immediately following intense activity, squirrels sought shade in a tree to facilitate cooling. Squirrels exhibited hypothermia in the nest during the day and night. A diurnal rhythm of Tb was observed in free—ranging squirrels when in the nest and similar rhythms of T_b and O_2 consumption rate (V_(O_2)) were observed in laboratory squirrels. Basking was common on winter afternoons and upon emergence from the nest in the morning throughout the year, resulting in elevated Tb values. Position of the tail appeared to moderate solar irradiation striking the squirrel during basking. When positioned dorsally, the tail increased reflectance. Wind and rain significantly reduced Tb in squirrels outside the nest. The relationship between Tb and Ta was subtle and difficult to ascertain in the field. In the laboratory, Tb decreased in response to falling Ta and subsequently metabolic expenditures were depressed from the expected. The mean field Tb during summer and early fall was significantly higher than during winter or spring and may indicate seasonal acclimatization. Squirrels in the field did not cache substantial quantities of food. They foraged daily and were active during all seasons, including inclement winter weather. Fresh snow appeared to restrict movements. Squirrels were seldom outside of the nests at Ta values < —10°C. Laboratory experiments established a thermoneutral zone between 29° and 35°C. Within the zone the Vo2 was 0.69 ml O2 (g h)—1 (standard temperature and pressure, dry) or 104% of the predicted weight specific value. The curve of thermogenesis is best described by a polynomial regression due to shifts in Vo2 caused by changes in Tb in response to falling Ta. The lower lethal limit was near —20 degrees C.

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Section: Food Cachingmentioning

confidence: 99%

Heterothermy in Free‐Ranging Abert's Squirrels (Sciurus Aberti)

Golightly¹,

Ohmart²

1978

Ecology

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“…In fall, squirrels occasionally bury single pine cones in shallow pits (F. M. Bailey 1932), and at least some of these are recovered during the winter. The squirrels apparently have not developed a strong instinct for storing pine cones since they must depend largely on other foods.…”

Section: Seeds Of Ponderosa Pinementioning

confidence: 99%

The Abert Squirrel and Its Dependence on Ponderosa Pine

Keith¹

1965

Ecology

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The Abert squirrel (Sciurus aberti aberti) occurs throughout the ponderosa pine belt in central Arizona where it appears to have become ecologically dependent on ponderosa pine. Studies of the squirrels and their relationship to ponderosa pine were conducted at the Fort Valley Experimental Forest and adjacent areas on the Coconino National Forest near Flagstaff, Arizona, between October 1953 and June 1955. Adult squirrels molt twice each year, and their summer and winter pelages are somewhat different in color shade and pattern. In a sample of 313 adult squirrels, males weighed an average of 589 g; females, 60 g. Body measurements are similar between sexes, except that females apparently have longer tails. The squirrels obtain most of their food from ponderosa pine. The inner bark of terminal twigs is the principal food during winter, and ovulated cones are preferred in summer. Staminate flowers and apical buds of pine are also important foods. Other foods include fleshy fungi, carrion, and bones. The home range of squirrels was determined in summer by trapping and in winter by mapping areas of activity in snow. On the average, squirrels ranged over about 18 acres during summer and five acres in winter. Squirrels are strictly diurnal and in 1954 were active and fed each day even in inclement weather. Abert squirrels build nests in the branches of ponderosa pine. These nests, composed of pine twigs, have an outside diameter of about one and one—half feet and an inside diameter of six inches. Squirrels do not prefer any particular site in the tree for their nest. They may occupy several nests during a year. In 1954 squirrels bred only in May at Fort Valley. The gestation period was estimated at about 40 days, and young squirrels were born between June 10 and July 12. Litter size varied from two to five and averaged 3.4. Of 729 squirrels collected during different years, 57% were male and 43% were female. Young squirrels had thick ear tufts in September, but on adults tufts were absent or very thin at that time. This difference is the best available criterion of age. The obvious causes of mortality did not appear to be responsible for the considerable losses that evidently occurred during the winter of 1953—54; other factors must have reduced squirrel densities. The number of feeding sites evident after fresh snows is a reliable indicator of squirrel density. Counts of the total number of twigs clipped by squirrels during winter appear to be related to population densities and differences between years should indicate trends in populations. In central Arizona squirrels are now apparently less numerous than at the turn of the century. This is probably due to the deterioration of squirrel habitat caused by logging and lack of adequate pine regeneration. Short—term fluctuations in population are believed to be caused by variations in quality and quantity of food supply which in turn may be related to the reproductive cycle of ponderosa pine. Intensive forest management should result in larger and more stable populations...

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“…Abert squirrels do not store food in large caches as do other tree squirrels of North America. In fall, squirrels occasionally bury single pine cones in shallow pits (F. M. Bailey 1932), and at least some of these are recovered during the winter. The squirrels apparently have not developed a strong instinct for storing pine cones since they must depend largely on other foods.…”

Section: Seeds Of Ponderosa Pinementioning

confidence: 99%

“…Bailey 1913;Mearns 1907;Merriam 1890;Warren 1910). In more recent years a few workers have reported more specifically on the habits of the squirrels (V. Bailey 1931;F. M. Bailey 1932;Goldman 1928;Hill 1942;Rice 1957).…”

Section: Introductionmentioning

confidence: 99%