An Urban, Suburban, Rural Red-Tailed Hawk Nesting Habitat Comparison in Southeastern Wisconsin
File(s)
Date
1995-04Author
Stout, William E.
Publisher
University of Wisconsin-Stevens Point, College of Natural Resources
Metadata
Show full item recordAbstract
Red-tailed hawks (Buteo jamaicensis) nesting in urban environments is
becoming more common, yet no studies have documented components of urban
nesting habitat. In this study I define, describe, and compare urban, suburban and
rural red-tailed hawk nesting habitat in southeast Wisconsin.
Nests were located from a vehicle between 1 February and 30 April from 1987
through 1994, and were visited periodically to determine reproductive success. Nest
site data were collected when nestlings were 2 to 5 wk old. Habitat data were
collected within a 0.04-ha circular plot around the nest tree after fledging. Land-use
data were collected within a 1.5-km radius (706.9 ha), and a 0.25-km radius (19.6 ha)
of the nests. A nest site was classified as urban if~ 70% of the 706.9-ha area was
used for industrial or residential purposes ( developed), rural if </= 30%, and suburban if
> 30% and< 70% was developed. The amount of natural, agricultural, residential and
industrial land-use within the 706.9 and 19.6-ha areas was determined from 1990 aerial
photos. Urban, suburban and rural nest sites were compared.
Productivity was not significantly different for urban, suburban and rural nest
sites (P = 0.857). Average nesting success for red-tailed hawks in the Milwaukee
metropolitan area from 1989 through 1994 (N:426) was 81.9% (R:75.3-92.7%).
Productivity for the same 6-yr period averaged 1.43 young/active nest (R:1.13-1.91)
and brood size at banding (2.5 to 5 wk) averaged 1.75 young/successful nest (R:1.61-
2.06). Productivity varied significantly (P < 0.001) being higher in 1994 than each of
the preceding yr (P:<0.001-0.015).
Nest trees for suburban sites were significantly taller than urban sites (P =
0.009) but not rural sites (P = 0.061). Nest closure was statistically identical for the
three categories (P = 0.978). Suburban sites had significantly more shrub diversity
than urban and rural sites (P = 0.017, P = 0.004, respectively), and had higher shrub
density than rural sites (P = 0.044). The 706.9-ha area for urban sites was
significantly more homogeneous than suburban and rural sites (P < 0.001, P = 0.001,
respectively). Distances between active red-tailed hawk nests for urban sites were >
for suburban and rural sites (P = 0.004, P < 0.001, respectively), and distances for
suburban sites were> rural sites (P = 0.018).
The amount of land with natural cover within the 706.9-ha area for urban nest
sites was significantly different for urban, suburban and rural sites (P < 0.001). The
amount of natural cover within the 19.6-ha area was identical for urban, suburban and
rural sites (P = 0.967). The amount of land with natural cover is a critical nesting
habitat component. Natural habitat comprised about 16% of the land within the 706.9-
ha area for urban sites; 40% of this area was wooded, and 60% had herbaceous cover.
Urban planning should incorporate these amounts of natural habitat to allow for red-tailed
hawks and other wildlife to coexist with humans in an urban environment.