The Wilson Journal of Ornithology 123(2):206-217, 2011 
AVIAN COMMUNITY AND MICROHABITAT ASSOCIATIONS OF 
CERULEAN WARBLERS IN ALABAMA 
JOHN P. CARPENTER, 143 YONG WANG, 1 CALLIE SCHWEITZER.-’ AND PAUL B. HAMEL' 
ABSTRACT.—Cerulean Warblers {Dendroicu cerulea) have experienced one of the highest population declines of any 
neotropical-Nearctic migratory species in North America. We performed point counts and habitat assessments in areas used 
and unused by Cendean Warblers in northern Alabama during the 2005 and 2006 breeding seasons to examine their avian 
associations and identify microhabitat features that best explained their occurrence. We detected on average —50 Cerulean 
Warbler males (total) in three disjunct populations during each breeding season. Areas used by Cerulean Warblers were 
characterized by avian communities with significantly higher species richness, diversity, and abundance compared to areas 
where they were not detected. Correspondence analysis related Cerulean Warblers to inhabitants of riparian, bottomland 
deciduous loresls (c.g.. Kentucky Warbler [Oporomisfonnosus], Acadian Flycatcher | Emptdonax virescens], and Northern 
Parula \Panda americana]) and two edge specialists (Blue-winged Warbler | Veminora cyanoptera ) and Indigo Bunting 
\Passerina cyaneu]) suggesting Cerulean Warblers in our study areas may be tolerant of some habitat disturbance within an 
otherwise largely forested landscape. Information theoretic criteria and canonical correspondence analysis indicated 
Cerulean Warblers preferred bottomland forests containing tall (> 29 m). large diameter, well-spaced (> 27 nr/hai 
deciduous trees with greater canopy cover (== 90%). closer « 20 m) canopy gaps, fewer snags < < 25/ha), and a moderately 
complex canopy structure. Received S March 2010. Accepted 22 December 2010. 
The Cerulean Warbler (Dendroica cerulea) has 
lost nearly 70% of its breeding population since 
1966 (Rich et al. 2004) because of alterations in 
breeding, migratory, and wintering habitats com¬ 
pounded by the bird’s dependency on extensive 
tracts of large deciduous trees in many parts of its 
range (Hamel 2000a). Northern Alabama histor¬ 
ically represented a portion of the Cerulean 
Warbler's southern-most breeding range where 
they were described as common and even 
numerous in several counties throughout the state 
(Imhof 1976). This warbler is now rarely 
encountered in Alabama during the breeding 
season and was designated a Priority One species 
(highest conservation concern) by the Alabama 
Department of Conservation and Natural Re¬ 
sources (Mirarchi et al. 2004). 
Selection of breeding territories by landbirds is 
heavily influenced by structure and composition 
of the surrounding habitat and avian community 
(MacArthur and MacArthur 1961, Wiens 1989) 
Department ot Natural Resources and Environmental 
Sciences, Alabama A&M University, p. O Box ]9^7 Nor 
mal. AL 35762, USA. 
2 USDA, Forest Service. Southern Research Station. P O 
Box 1568, Normal, AL 35762, USA. 
'USDA, Forest Service, Center lor Bottomland Hard¬ 
woods Research, P. O. Box 227, Sloneville. MS 38776, 
5 Corresponding author; e-mail: 
john.carpenter@ncwildlifc.org 
Thus, effectiveness of management initiatives is 
dependent upon not only identifying the habitat 
requirements of the species under investigation, 
but also the avian community with which it 
associates. Recent studies of Cerulean Warblers 
emphasize breeding habitat requirements (Rob¬ 
bins et al. 1992, Jones and Robertson 2001, 
Weakland and Wood 2005. Barg et al. 2006b). 
nesting behavior (Oliarnyk and Roberston 1996. 
Barg et al. 2006a. Rogers 2006. Roth and Islam 
2008). and habitat management (Hamel 2005, 
Hamel et al. 2005b, Hamel and Rosenberg 2007). 
while information regarding avian associations of 
Cerulean Warblers remains scarce (Jones et al. 
2004) and anecdotal (Lynch 1981. Hamel 2000b). 
Recent discoveries of two small Cerulean 
Warbler populations in Alabama suggest habitat 
is available in this portion of the species range to 
support small breeding populations (Carpenter et 
al. 2005). This study was initiated in response to 
the Rosenberg et al. (2000) recommendation for 
additional Cerulean Warbler research in Alabama 
to provide more accurate population estimates and 
habitat requirements needed to effectively manage 
habitat for this species. Our objectives were to: (1) 
examine avian associations of the Cerulean 
Warbler to facilitate a better understanding of 
this species' habitat use and the bird community 
in which it breeds, and (2) identify microhabitat 
features that best explain Cerulean Warbler 
occurrence in the southern portion of its range 
where populations are in serious decline (Buehler 
et al. 2008). 
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