We used 37 years of North American Breeding Bird Surveys to test for effects of periodical cicada (Magicicada spp.) emergences on the abundance and spatial synchrony of 24 species of avian predators in hardwood forests of the eastern United States. Fifteen (63%) of the bird species exhibited numerical changes in abundance apparently associated with emergences of the local periodical cicada brood, and intraspecific spatial synchrony of bird abundance was significantly greater between populations sharing the same cicada brood than between populations in the ranges of different broods. Species exhibited at least four partially overlapping temporal patterns. (1) Cuckoos (Coccyzus spp.) occurred in high numbers only during emergence years and subsequently declined in abun-dance. (2) Red-bellied Woodpeckers (Melanerpes carolinus), Blue Jays (Cyanocitta rris-tata), Common Orackles (Quiscalus quiscula), and Brown-headed Cowbirds (Molothrus ater) increased significantly 1-3 years following emergences and then declined. (3) Red-headed Woodpeckers (Melanerpes erythrocephalus), American Crows (Cowus hrachyryn-chos), Tufted Titmice (Baeolophus hicolor); Gray Catbirds (Dumetella carolinensis), and Brown Thrashers (Toxostoma mfum) were found in significantly low numbers during emer-gence years, underhrent significant numerical increases in the following year, and then stabilized. (4) Wood Thrushes (Hylocichla rnustelina), Northern Moclsingbirds (Mimuspo-ZygIottos), Northern Cardinals (Cardinalis cardinalis), and House Sparrows (Passer do-mesticus) exhibited significantly deviant population numbers 1-2 years prior to emergences, below the long-tern meaa in the first two species and above the long-term mean in the latter hyO" These results suggest that the pulses of resources available at 13-or 17-year intervals when periodical cicadas emerge have significant demographic effects on key avian predators, mostly during or immediately after emergences, but in some cases apparently years following emergence events.
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