conservation.arizona.edu - mixed conifer forests

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

Edelman, A. J. and J. L. Koprowski. 2006. Seasonal changes in home ranges of Abert's squirrels: Impact of mating season. Canadian Journal of Zoology 84: 404-411.

thackerk1 — Tue, 25 Jun 2019 01:06:09 +0000

Authors

A.J. Edelman

J.L. Koprowski

We compared home ranges of introduced Abert’s squirrels (Sciurus aberti Woodhouse, 1853) in mixed- conifer forests of Arizona during non-mating and mating seasons. Because Abert’s squirrels are reported to depend on ponderosa pine (Pinus ponderosa P. & C. Lawson) forests, the mixed-conifer forest in our study represented a novel habitat. Home-range size, home-range overlap with females, and movement distances increased for males from non-mating to mating seasons. Home-range size and overlap characteristics of females remained consistent between seasons, but movement distances were reduced during the mating season. Males probably increased home-range size, home-range overlap with females, and movement distances during the mating season to maximize contact with scarce females. Home-range size and overlap characteristics of female Abert’s squirrels likely remained stable between seasons because females do not search for mates. Restricted movements by females during the mating season may be due to changes in resource use in preparation for reproduction. Non-mating season home ranges in our study were smaller than home ranges observed in ponderosa pine forest. Abert’s squirrels in mixed-conifer forest may have small home ranges because resource quality is higher than in ponderosa pine forest or competition for space with co-occurring Mount Graham red squirrels (Tamiasciurus hudsonicus grahamensis (J.A. Allen, 1894)).

Additional Information

Seasonal changes in home ranges of Abert’s squirrels: impact of mating season

Date of publication:

2006

Topics

Abert’s squirrels

mixed conifer forests

home range

resource quality

sex differences

seasonal changes

mating season

Doumas, S. L., J. L. Koprowski, and W. O. Noble. 2016. Landscape-level assessment of Abert's squirrel and red squirrel in mixed conifer forest. The Southwestern Naturalist 60:240-246.

thackerk1 — Tue, 25 Jun 2019 00:36:36 +0000

Authors

Sandra L. Doumas

John L. Koprowski

William O. Noble

We examined feeding sign of Abert’s squirrels (Sciurus aberti) and red squirrels (Tamiasciurus hudsonicus) each spring 2005–2009 in mixed conifer forests in northern Arizona, USA. We used high- resolution aerial photographs to assess vegetation characteristics where feeding sign surveys were conducted and analyzed the association of feeding sign frequency to vegetation characteristics to compare and contrast species habitat use. At the landscape level, we found considerable overlap in characteristics of forests used by the two species of native tree squirrels. Red squirrels used denser forests with fewer and smaller gaps than do Abert’s squirrels, and Abert’s squirrels used more ponderosa pine (Pinus ponderosa) than do red squirrels.

Additional Information

Landscape-level assessment of Abert's Squirrel and Red Squirrel in Mixed Conifer Forest

Date of publication:

2015

Topics

Abert’s squirrels

red squirrels

feeding signs

mixed conifer forests

habitat use