| Nest
site selection by Cactus Ferruginous Pygmy-owls
in southern Arizona |
| |
 Background:
The distribution and density of cactus ferruginous pygmy-owls (Glaucidium
brasilianum cactorum) may be limited by the availability of suitable
nesting habitat. Consequently, it is important to identify specific
structural characteristics used by pygmy-owls when selecting a place
to nest. Presently, large columnar cacti represent the primary known
cavity substrate used for nesting by pygmy-owls in Sonoran desertscrub.
Current data limitations preclude any credible prediction of potential
nesting habitat. This project proposes to identify habitats selected
by nesting pygmy-owls in Sonoran desertscrub habitat.
Location:
We will focus our survey efforts in those portions
of Pima and southern Pinal counties where nesting
pygmy-owls have been located in the past. Currently
most of the known nesting pygmy-owls occur
within the Sonoran desertscrub upland habitat
in the northern Tucson Basin and Altar Valley.
Approach:
 We
will characterize the structure and composition
of vegetation at known pygmy-owl nest sites.
Within a 15m diameter circular plot centered
on each identified nest we will measure density
of cacti and woody plants, non-herbaceous plant
species composition, index of vertical vegetation
density, tree crown diameter, and percent ground
cover. We will also measure the following physiographic
variables: distances to nearest road, man-made
structure, available water, and desert wash.
In addition to these variables, the cavity
aspect, internal dimensions, height from the
ground and diameter will be measured.
Benefits:
Research results will also provide useful information about the distribution
of pygmy-owls in southern Arizona. Identifying the habitat requirements
of pygmy-owls will better enable wildlife managers and urban planners to
develop management prescriptions that can ensure future viability of pygmy-owls
in Arizona.
For more information
contact:
Michael Ingraldi, Arizona Game and Fish Department, 5000 W. Carefree Highway Phoenix, AZ 85086-5000
.
Phone: (928) 523-5625 E-mail: mingraldi@cybertrails.com
Shawn Lowery, Arizona Game and Fish Department, 5000 W. Carefree Highway Phoenix, AZ 85086-5000
.
Phone: (520) 742-1911 E-mail: slowery@gf.state.az.us |
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