Neighbor-joining phylogenetic tree based on 433 nucleotides of B. andersonii 16S-23S rRNA IGS haplotypes collected from Pitsfield Banding Station, 2004–2007. A sequence of B. burgdorferi obtained from GenBank was included as the outgroup. The percentages of replicate trees in which the associated taxa clustered together in the bootstrap test (1000 replicates) are shown next to the branches when 80 or higher. Sequences are labeled with the name of the tick species from which B. andersonii was amplified followed by the tick life stage/sex (NN = nymph; LL = larval pool; AF = adult female) and a four-letter alpha code indicating the avian host (AMRO = American Robin; BHCO = Brown-headed Cowbird; BRTH = Brown Thrasher; CONW = Connecticut Warbler; ETTI = Eastern Tufted Titmouse; GRCA = Gray Catbird; HETH = Hermit Thrush; NOCA = Northern Cardinal; PUFI = Purple Finch; SOSP = Song Sparrow; SWTH = Swainson’s Thrush) or RABBIT indicating the eastern cottontail, a laboratory identification code, followed by the GenBank accession number. The single sequence derived from rabbit ear tissue is labeled with ‘EAR’. The asterisk and dagger denote samples from the same individual host.