From September 1997 through July 1999, 300 individuals and 46 species of birds 
were mist-netted and screened for ticks and spirochetes on St. Catherine's 
Island, Liberty County, GA. Seventy-six (25%) of the birds were parasitized by a 
meal intensity of 4.6 ticks. Seasonally, more birds were infested with ticks 
during the summer (50% in 1998, 34% in 1999) than in spring (15% in 1998, 11% in 
1999) or fall (21% in 1997, 20% in 1998), mainly because of severe infestations 
on some birds by immature stages of the lone star tick, Amblyomma americanum 
(L.), during this season. Eight species ofticks were recovered from 14 species 
of birds during this study: A. americanum (74 nymphs, 168 larvae); the 
blacklegged tick, Ixodes scapularis Say (11 nymphs, 28 larvae), the Gulf Coast 
tick, Amblyomma maculatum Koch (two nymphs, 29 larvae); Ixodes minor Neumann (16 
larvae); the rabbit tick. Haemaphysalis leporispalustris (Packard) (one nymph, 
14 larvae); the bird tick Ixodes brunneus Koch (two larvae); the American dog 
tick, Dermacentor variabilis (Say) (one nymph); and Ixodes affinis Neumann (one 
larva). The Carolina wren was parasitized by more species of ticks (seven) than 
any other bird species, followed by the northern cardinal (five), white-throated 
sparrow (four) and painted bunting (three). Spirochetes were isolated in BSK II 
medium from one tick (a nymphal A. americanum) and from skin biopsies of 12 (4%) 
of the individual birds (three downy woodpeckers, three northern waterthrushes, 
two Carolina wrens, one American redstart, one pine warbler, one Swainson's 
thrush, and one white-eyed vireo) all in fall 1997. This concentrated phenology 
of spirochete isolations might reflect periodic amplification or recrudescence 
of spirochetes in reservoir avian hosts.