Jl. Bell et Rc. Whitmore, BIRD POPULATIONS AND HABITAT IN BACILLUS-THURINGIENSIS AND DIMILIN-TREATED AND UNTREATED AREAS OF HARDWOOD FOREST, The American midland naturalist, 137(2), 1997, pp. 239-250
The objective of this study was to evaluate the effects of a gypsy mot
h (Lymantria dispar) infestation on nongame bird populations and habit
at This study was conducted at the Sleepy Creek Public Hunting and Fis
hing Area in Morgan and Berkeley counties, and Cacapon State Park in M
organ County, in the eastern panhandle of West Virginia We compared an
area that was repeatedly defoliated by the gypsy moth (Sleepy Creek)
to an area (Cacapon) that was sprayed,vith Dimilin and Bt to control g
ypsy math populations. Both areas were sampled in 1984, before defolia
tion or spraying, and afterwards in 1993. Tree mortality caused by gyp
sy moth defoliation created gaps in the canopy, increasing habitat pat
chiness at Sleepy Creek, but did not negatively affect total bird dens
ity. Greater habitat complexity (particularly increases in snags, wind
fall and shrub cover) after the gypsy moth outbreak may have increased
available nesting and foraging resources for many bird species. While
habitat for some flycatchers and canopy-dwelling species was reduced
at Sleepy Creek, sufficient canopy was left after defoliation to suppo
rt similar numbers of these birds. Despite dramatic visual effects, gy
psy moth impact may not be permanently damaging to bird populations an
d may even be beneficial for some species. However, other factors, suc
h as insect availability, nesting success, predation and cowbird paras
itism need to be examined in gypsy moth-impacted areas to better asses
s effects of defoliation on bird populations.