conservation.arizona.edu - cavity nests

Young, P. J., V. L. Greer, and S. K. Six. 2002. Characteristics of Bolus Nests of Red Squirrels in the Pinaleño and White Mountains of Arizona. The Southwestern Naturalist 47: 267-275.

thackerk1 — Tue, 30 Jul 2019 21:51:57 +0000

Authors

Paul J. Young

Vicki L. Greer

Sheri K. Six

Red squirrels (Tamiasciurus hudsonicus) use cavity, bolus, and underground nests for sleeping, protection, and rearing of young. We compared occurrence and structural characteristics of bolus nests at midden sites (area surrounding the central cache) for red squirrels in the Pinaleno Mountains with those in the White Mountains of southeastern Arizona. Bolus nests were more prevalent in the White mountains, possibly as a result of differing habitat structure; forests of the Pinaleno Mountains had significantly (P < 0.05) larger basal area, greater stem densities, and there was less grass on the forest floor than in the White Mountains. Midden sites with more potential cavity nest sites were more likely to have only cavity nests present. Bolus nests were constructed mostly of lichens in the Pinaleno Mountains and of grasses in the White Mountains, whereas most other nest and nest tree characteristics were similar between locations, although nest trees were further from the main cache location at middens in the Pinaleno Mountains.

Additional Information

Characteristics of Bolus Nests of Red Squirrels in the Pinaleno and White Mountains of Arizona

Date of publication:

2002

Topics

red squirrel

nest sights

midden sites

Pinaleño Mountains

cavity nests

bolus nests

underground nests

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. 2006. Characteristics of Abert's squirrel (Sciurus aberti) cavity nests. The Southwestern Naturalist 51(1): 64-70.

thackerk1 — Tue, 25 Jun 2019 01:18:08 +0000

Authors

Andrew J. Edelman

John L. Koprowski

Cavity nests are rarely used by Abert's squirrels (Sciurus aberti) in ponderosa pine (Pinus ponderosa) forests. Introduced Abert's squirrels in the Pinaleño Mountains of Arizona, however, exhibit occasional use of cavity nests (ca. 10%). We examined characteristics of cavity nest sites in this introduced population. Cavity nests were located at two-thirds of the tree height and were found mainly in both dead and live aspen (Populus tremuloides). Aspen cavity trees were larger than aspen random trees. Aspen cavity sites had more large snags and less ponderosa pine and were less steep than aspen random sites. Abert's squirrels possibly use cavities in large aspen trees because thick trunks and older trees might allow larger cavities to form, might provide greater thermal and wind protection, or both. The greater use of cavity nests by the Abert's squirrels in our study could be due to the higher frequency of cavity-forming aspens or harsher winter conditions in mixed-conifer forests of the Pinaleño Mountains than in ponderosa pine forests where Abert's squirrels typically occur or both.

Additional Information

CHARACTERISTICS OF ABERT'S SQUIRREL (SCIURUS ABERTI) CAVITY NESTS

Date of publication:

2006

Topics

Abert’s squirrels

cavity nests

aspen

ponderosa pine

mixed conifer forests

Pinaleño Mountains