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THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 3. September 2011 
underlain by an extensive glacial outwash plain 
and a system of parabolic sand dunes (30 m max 
height) that is uniquely large and extensive 
compared to other northeastern pine barrens 
(Barnes 2003). Development, soil disturbance, 
and fire suppression between 1940 and 1990 
resulted in an 81% change of land cover with 40% 
attributed to permanent habitat removal and 41% 
resulting from changes in plant community 
composition and structure (Finton 1998). Nearly 
half of the plant community change that occurred 
during this period (18% of total land cover) was 
replacement of pitch pine-scrub oak barrens and 
thickets with a closed-canopy deciduous forest, 
dominated by non-native, highly invasive black 
locust (Robinia pseudoacacia) (Finton 1998). The 
APBP is physically fragmented by a network of 
interstate and local highways, which create 
distinct blocks of protected lands adjacent to 
commercial, residential, and agricultural land 
uses. Ecosystem management, including pre¬ 
scribed fire, mowing, invasive plant removal, 
and restoration planting has been applied to 
>500 ha of the Preserve since 1991. The portion 
of the Preserve where we conducted our survey 
has supported a mosaic of open- and closed- 
canopy pitch pine-scrub oak communities since 
before 1928 (Finton 1998). The survey area 
contains the largest remaining block (56 ha) of 
pitch pine-scrub oak barrens in the APBP. 
encompassing several management units domi¬ 
nated by an open-canopy pitch pine overstory and 
a relatively dense mosaic of scrub oak and 
ericaceous shrubs in the understory. Sections of 
the sampled area experienced wild or prescribed 
fire in 1981, 1994, 1995, 1999. and 2005. 
Mist Netting.—We deployed 6-8 mist nets (6- 
12 m long. 32-36 mm mesh) along a 0.5-km 
transect during fall migration 2007. 2008, anc 
2009. We began our survey in late August 200: 
and continued until early November to insure tha 
we sampled the full extent of the migrator] 
period. We focused on the 6-week period firm 
early-September to mid-October in subsequen 
years. Nets were placed on dune ridges perpen 
dicular to the established foot path through tin 
Preserve. Nets were opened at dawn (0530 hrs it 
early weeks. 0630 hrs in late weeks) and operatet 
until 1030 hrs, 2-4 days per week. Nets wen 
checked every half-hour and birds were removet 
to doth bags for processing. Individuals o 
resident, non-migratory species (e.g.. Downy 
oodpecker I Pwoides pubexcens], Black-cappec 
Chickadee [Poecile atricapillus ], Blue Jay fCyo- 
nocitta crista fa}), and of migratory species known 
to breed on the Preserve (e.g.. Gray Catbird 
I Dumerella carolittensis 1, Eastern Bluebird |Sin/w 
sialis]) were immediately released. Captured 
migrants were marked with a single aluminum 
USGS leg band, sampled for a single flight 
feather, measured, weighed, and released. We 
classified the age and sex of each bird when 
possible, but did not attempt to characterize the 
demographics of the fall migrant avifauna. 
Stable Isotope Analysis .—We pulled a single 
fiight feather (remex or rectrix) from each migrant 
and placed the feather in separate paper enve¬ 
lopes. We selected six species following our final 
field season on which to conduct hydrogen 
isotope analysis on the basis of sample size (> 
5 individuals captured) and because they are 
known to completely molt all flight feathers on 
breeding areas prior to migration. These were 
Ruby-crowned Kinglet (Hegulus calendula), 
Nashville Warbler (Oreothlypis ruficapilla), Mag¬ 
nolia Warbler (Dendroica magnolia). Palm War¬ 
bler (D. palmcirum), Blackpoll Warbler (A 
striata), and Lincoln’s Sparrow (Melospiza I'm 
colnii) Information on molt schedules was 
obtained from individual Birds of North Amenca 
species accounts (Ammon 1995, Williams 1996, 
Wilson 1996, Hunt and Eliason 1999, Swanson d 
al. 2008. Dunn and Hall 2010). These species 
have broad breeding ranges well north of our 
study site, extending across the boreal forest zone 
of the U.S. and Canada west to the Canadian 
Rockies (Nashville Warbler, Palm Warbler) or to 
Alaska (all other species). Two species (Magnolia 
Warbler, Nashville Warbler) have breeding ranges 
that extend into the temperate forest zone south'^ 
the study site. 
We washed each feather to remove dirt are 
oils, first with a 0.1% Tween-20 detergeni 
solution followed by two rinses in purified water 
This was followed by two rounds of washing w J 
2:1 chloroform:methanol solvent solution, earl' 
followed by rinsing in purified water. Cleaned 
teathers were placed in new paper envelopes an- 
mailed to Colorado Plateau Stable Isotope l-ah v 
ratory (CPSIL) at Northern Arizona University 
(Flagstaff) for weighing, encapsulation in fin. a nt 
hydrogen isotope-ratio mass spectrometry- ^ 
CPSIL uses a DELTA plus XL Thermo Electro" 
gas isotope-ratio mass spectrometer to measu 11 - 
the hydrogen isotope ratio (5£>,-) from each Ie4 he ' 
sample. Machines and procedures are calibrateo 
