Ramos-Lara, N., J. L. Koprowski, and D. E. Swann. 2013. Nest-site characteristics of the montane endemic Mearns's squirrel (Tamiasciurus mearnsi): an obligate cavity-nester? Journal of Mammalogy 94:50-58.

thackerk1 — Tue, 30 Jul 2019 18:09:11 +0000

Authors

Nicolás Ramos-Lara

John L. Koprowski

Don E. Swann

Many animals depend on nests for their survival and reproduction, with some species considered obligate tree cavity-nesters. Mearns’s squirrel (Tamiasciurus mearnsi) is a species endemic to the Sierra de San Pedro Mártir, Baja California, Mexico, that relies on tree cavities for nesting. Federally listed as threatened in Mexico, and as endangered by the International Union for Conservation of Nature, the ecology of this southernmost Tamiasciurus is poorly known. The aim of this study was to examine the nesting requirements of Mearns’s squirrels. We used telemetry to locate the nests and 10-m-radius circular plots to compare habitat characteristics between nest sites and random sites, nest sites of males and females, and nest sites of breeding and nonbreeding females. Nest tree species, nest tree condition, nest tree size (diameter at breast height), canopy cover, and occurrence of white firs (Abies concolor) are important characteristics for nesting. Nest sites of males did not differ from those of females except for nest tree condition. Females apparently do not have specific nesting requirements for rearing young. Unlike other congeners that also build leaf nests and underground burrows for nesting, large trees and snags that facilitate cavity formation are critical for the conservation of this species.

Additional Information

Nest-site characteristics of the montane endemic Mearns’s squirrel (Tamiasciurus mearnsi): an obligate cavity-nester?

Date of publication:

2013

Topics

cavity nests

endemic species

nest sites

tree cavities

Mearn’s squirrel

Edelman, A. J. and J. L. Koprowski. 2005. Diet and tree use of Abert's squirrels (Sciurus aberti) in a mixed-conifer forest. The Southwestern Naturalist 50(4): 461-465.

thackerk1 — Thu, 27 Jun 2019 20:58:17 +0000

Authors

Andrew J. Edelman

John L. Koprowski

Abert’s squirrels (Sciurus aberti) are reported to be dependent on ponderosa pine (Pinus ponderosa) forests for food, cover, and nest sites. Introduced Abert’s squirrels in the Pinaleño Mountains of Arizona, however, occupy forests that contain little to no ponderosa pine. We documented diet and tree use of Abert’s squirrels in mixed-conifer forests of the Pinaleño Mountains using observations of marked animals. Individuals ate similar food items as Abert’s squirrels in ponderosa pine forests, including seeds, inner bark, buds, and fungi, but 5 conifer species were used as food sources. Douglas-fir (Pseudotsuga menziesii) and southwestern white pine (Pinus strob- iformis) were the most frequently eaten conifer species. Abert’s squirrels also were observed in all tree species. Our results suggest that the dependence of Abert’s squirrels on ponderosa pine is not as strong as previously reported.

Additional Information

DIET AND TREE USE OF ABERT'S SQUIRRELS (SCIURUS ABERTI) IN A MIXED-CONIFER FOREST

Date of publication:

2005

Topics

Abert’s squirrels

mixed-conifer forests

Pinaleño Mountains

diet

nest sites

conservation.arizona.edu - nest sites

Ramos-Lara, N., J. L. Koprowski, and D. E. Swann. 2013. Nest-site characteristics of the montane endemic Mearns's squirrel (Tamiasciurus mearnsi): an obligate cavity-nester? Journal of Mammalogy 94:50-58.

Authors

Additional Information

Topics

Edelman, A. J. and J. L. Koprowski. 2005. Diet and tree use of Abert's squirrels (Sciurus aberti) in a mixed-conifer forest. The Southwestern Naturalist 50(4): 461-465.

Authors

Additional Information

Topics