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THE WILSON JOURNAL OF ORNITHOLOGY • Vol 124. No. 4. December 2012 
on nestling Red-shouldered Hawks in two regions 
of southern Ohio: suburban southwestern Ohio 
(SWOH) and rural, forested Hocking Hills (HH) 
in south-central Ohio. 
METHODS 
Study Areas. —The SWOH study area is a hilly, 
unglaciated area in the Interior Plateau ecoregion 
(Omernik 1987). The hills are dissected by many 
small streams in ravines and two large rivers, the 
Great Miami River and the Little Miami River. 
Native forests are dominated by second-growth 
oak ( Quercus spp.)-hickory (Carya spp.) and 
beech ( Fagus gramlifolia)-sugar maple (Acer 
saccharin,,) associations with lowland, riparian 
forests characterized by sycamores ( Platanus 
occidcmtalis) and beech. Elevation ranges from 
~140 to 270 m. 
I he SWOH study area consisted of Hamilton 
County, Clermont County, and southwestern 
Warren County. Ohio; the nests studied were in 
a wide band of suburban development surround¬ 
ing the city of Cincinnati, Ohio. Suburban areas 
varied from densely-populated (residential lots 
20 x 35 m) to sparsely-populated (>2.5-ha 
residential lots, as well as undeveloped private 
land). Most residences and other buildings were 
surrounded by lawns and other non-native vege¬ 
tation. but residences tended to he on level ground 
with native vegetation on steep slopes and in 
riparian areas. 
Hocking Hills is a hilly, unglaciated region 
withm the Western Allegheny Plateau ecoregion 
m southeastern Ohio (Omernik 1987), -180 km 
east of SWOH. This region contains numerous 
small, high-gradient streams, as well as the larger 
Hocking River and many mid-size streams 
Elevation ranges from -200 t0 310 m The 
dominant forest type is oak-hickory. Drier sites 
include chestnut oak (Quercus minus) and black 
oak (Q velutma). and mesie slopes are charac¬ 
terized by tulip-tree (Uriodendroit tulipifera). 
Plantations of white (Pinas strohus) and red (P 
resmosa) pine are also common on public lands 
Western portions of this study area also feature 
sandstone gorges containing northern microcli¬ 
mates and habitats, including eastern hemlock 
{Tsuga canadensis) and ferns. Lowland forests are 
characterized by sycamores, silver maple (Acer 
saccharinum), beech, and river birch (Betula 
nigra). u 
The HH study area consisted of Hocking 
County, eastern Vinton County, northern Athens 
County, and southern Perry County, including the 
Athens District of Wayne National Forest, 
Hocking State Forest, Zalcski State Forest, and 
associated private lands. Proximity to human 
activities varied widely with some areas contain¬ 
ing residential development, some with recrea¬ 
tional development such as picnic areas and trails, 
and some areas were fairly remote. 
Location oj Nests and Measurement of Nest- 
/mgs. Red-shouldered Hawk nest locations were 
previously known to us from an ongoing long¬ 
term study (Dykstra et al. 2000. 2004.2009). Wc 
visited known nesting areas at least once (but 
typically 2-3 limes) between mid-February and 
mid-May. 2009-2011. and viewed nests from the 
ground using 8 x or 10 X binoculars or a 20-60 
spotting scope. Red-shouldered Hawks do not 
always re-occupv the same nest in subsequenl 
years, and it was often necessary to search for the 
new nest within a nesting area in the following 
year. We generally considered that a new nest 
0.5 km from a previously active nest was within 
Hie same nesting area. A nest 0.5-0.8 km from a 
previously active nest was considered to he within 
die same nesting area if additional evidence 
supported that conclusion (e.g., a bird seen flying 
between the original and new nests, a lack of 
activity at the original nest in subsequent years, a 
temporal progression of new nests moving in that 
direction indicating a shift of the nesting area's 
oundaries). We visited some nesting areas in 
more than I year, but data from only the first year 
were included in this study; thus nests in this 
study were independent in that each represented a 
unique nesting area. 
^ e included only nests where young or signs of 
young (excreta on ground and branches) were 
observed. We climbed to nests containing young 
m SWOH and in HH between 7 May and 15 June 
“ ) )-_() 11 | 0 examine and band young when 
nestlings were -2-5 weeks of ace.’ We'banded 
nestlings with USGS aluminum bands and 
weighed them using a 1.000-g spring scale to 
the nearest 5 g. We used a standard 33-cm ruler to 
mcasuie the length of the first and second 
secondary to the nearest millimeter. 
^ e examined the ears of each nestling and 
classified their infestation status as: (I) no larvae. 
G) larvae present within ear or ears, or (3) 
'larvae-evidence 7 outside of ear or ears, hut no 
aiyie observed. 'Larvae-evidence 7 was defined 
us the presence ol black crusty material below the 
ears (excreta from larvae). This material was 
