The Wilson Journal of Ornithology 123(3):548-556, 2011 
STABLE ISOTOPE ANALYSIS OF FALL MIGRATION STOPOVER BY 
SIX PASSERINE SPECIES IN AN INLAND PITCH PINE-SCRUB 
OAK BARREN 
JEREMY J. KIRCHMAN, 14 JOEL RALSTON,' 2 AND NEIL A. GIFFORD 3 
ABSTRACT.—We conducted mist-net surveys of migrating songbirds during fall migration 2007-2009 on the 1.300-ha 
Albany Pine Bush Preserve (APBP), a fire-managed inland pitch pine-scrub oak (Pinus rigida-Quercus spp.) barren in 
east-central New York. We banded 244 migrating passerines tmm 32 non-resident species in 8,610 net/m/hr documenting 
use of northeastern pine barrens as stopover sites for passerines with diverse breeding ecologies. We estimated the hreeding 
site origin of six species (a kinglet, lour warblers, and a sparrow) using stable hydrogen isotope measurements from flight 
leathers. There was a broad range of isotope ratios within each species indicating a large catchment area extending several 
hundred kilometers north and west of the stopover site. Over half the birds originated >750 km from the APBP We found 
no evidence for geographical structure of the timing of migration through APBP; slopes of regression lines for capture date 
versus hydrogen isotope ratio from feathers (SO,) were not statistically different from zero. This contrasts with previous 
isotope research that reports both leapfrog and chain migration patterns by different warbler species at stopover sites in the 
western United States. Received 29 October 2010. Accepted 4 March 2011. 
Pine (.Pinus spp.) barrens are globally rare, 
pyrogenic, early-successional ecosystems that 
support unique assemblages of species including 
many rare and declining taxa (Finlon 1998, 
Barnes 2003, Latham 2003, Wagner et al. 2003). 
Pine barrens in the northeastern United States arc 
dry, nutrient-poor systems restricted to glacial 
outwash plains and ridges with shallow soils 
(Barnes 2003). Historically, these habitats were 
inhospitable to agriculture and remained undevel¬ 
oped, but extensive suburbanization and suppres¬ 
sion of wildland tire have reduced the region's 
pine barrens and other early-successional habitats 
>50% since the 1960s (Trani et al. 2001). There 
are <20 significant pine barrens remaining in the 
northeastern U.S. including three large, mostly 
contiguous coastal barrens and several smaller 
inland pine barrens (Fig. 1). Pine barrens transi¬ 
tion to close-canopy forest in the absence of 
recurring fire (Finton 1998), but extant barrens 
appear to have persisted since glacial retreat 
12,000-18,000 years ago (Barnes 2003) making 
them uniquely stable habitat for early-succession¬ 
al wildlife species. 
Early-successional habitats in northeastern U.S. 
pine barrens are maintained almost exclusively 
through active management (Trani et al. 2001). 
The important targets of these efforts include 
'New York State Museum, 3140 Cultural Education 
Center. Albany, NY 12230. USA. 
* University at Albany, Albany. NY 12222. USA. 
'Albany Pine Bush Preserve Commission, 195 New 
Karner Road, Albany, NY 12205, USA. 
4 Correspondence author; e-mail: jkirchma@mail.nysed.gov 
shrubland birds, the most conservation-reliant 
(sensu Scott el al. 2010) avian group in the region 
(Hunter et al. 2001, Deltmers 2003). Several 
studies have documented a 40+ year decline of 
shrubland and disturbance-dependent bird species 
(Brawn et al. 2001, Deltmers 2003), yet few 
published studies have described species—habitat 
relationships for birds breeding in northeastern 
pine barrens (Kerlinger and Doremus 1981a, b; 
Morimoto and Wasserman 1991; Grand et al. 
2004; Beachy and Robinson 2008; Gifford et al, 
2010). We know of no study that has documented 
the use of pine barrens as migratory stopover sites. 
It is now well-recognized that events throughout 
the annual cycle are critical to survival of bird 
populations including factors in breeding and 
wintering areas, as well as at migratory stopover 
sites (Webster and Marra 2005). Migratory stop¬ 
over sites are critical diurnal foraging areas for 
nearly all nocturnal migrants. Foraging resources 
and predation pressures differ among stopover 
habitats with important fitness consequences for 
migrants (Moore et al. 1995). Migrants select 
among alternative habitats and use stopover sites 
that maximize foraging efficiency (Moore and 
Abom 2000). Most research on stopover sites has 
focused on woodland or riparian habitats (Winker 
et al. 1992, Wang et al. 1998). but some studies 
indicate that shrubland and forest interior breeding 
species rely disproportionately on early succes- 
sional habitats during autumn migration (Rode 
wald and Brittingham 2004). Migratory connectiv¬ 
ity of breeding and stopover sites has demographic, 
evolutionary, and conservation consequences 
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