McElhone et at. • HABITAT CHANGE AND CERULEAN WARBLERS 
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FIG. I. West Virginia, Kentucky, and Ohio portions of three Partners in Flight physiographic regions (Ohio Hills, N. 
Cumberland Plateau, and Mid Atlantic Ridge and Valley in bold outline) with locations of 28 BBS routes with stop-level 
coordinates analyzed in this study. 
coniferous from deciduous trees. Six of the 88 
BBS routes in the study area (5 routes in West 
Virginia, 1 in Ohio) had aerial photographs 
available for appropriate years and met our three 
criteria for inclusion. Aerial photographs were 
available for 240 stops on all six routes for the 
middle to late time period but for only 68 stops on 
two routes for the early to middle time period 
(Table 1). Photographs from all time periods were 
rectified and digitized in ArcMap, Version 9.2 
(ESRI, Redlands, CA. USA), Aerial photographs 
from different years or sources had different 
resolutions, and we digitized land cover at the 
minimum scale available (1:60,000). We digitized 
land cover into four types: a combined deciduous/ 
mixed forest type, coniferous forest, developed, 
and agriculture. We distinguished between decid¬ 
uous/mixed and coniferous forests because Ceru¬ 
lean Warblers are not known to use coniferous 
forests (Hamel 2000a). The agriculture land cover 
collapsed all remaining types not included by the 
three other land cover types and was dominated 
by agricultural land. 
Twenty-eight BBS routes with 1,375 stops 
(Table 1) met criteria to be included for compar¬ 
ison of the 1992 and 2001 NLCD data. Develop¬ 
ment is an important land cover class that is 
changing over time along BBS routes, but we 
were not able to use this class for the NLCD data 
sets. Small, secondary roads were not classified in 
the 1992 NLCD. but in 2001 they were classified 
as the developed type (Vogclmann et a1. 2001, 
Homer et al. 2004). Thus, differences in devel¬ 
oped area around a BBS sfop could be the result of 
different classification methods rather than a 
change in land cover; thus, we combined 
