Studies abound on how far north Ixodes scapularis ticks are transported by birds

Several studies report migratory songbirds transporting ticks northward during spring migration in Canada. The blacklegged tick, Ixodes scapularis, has been documented on Neotropical songbirds as far as Slave Lake, Alberta during northbound spring migration. In addition, Ixodes ticks have been collected from passerine migrants as far north as Watson Lake, Yukon (north of 60th latitude). The presence of Amblyomma ticks parasitizing long-distance migrants, which are moving from wintering grounds in the Neotropics to breeding grounds in Canada, confirms Neotropical songbirds transport ixodid ticks into Canada. Our avian, tick-host studies document 22 species of ticks on wild birds in Canada, and the majority of these species are not indigenous in Canada. Some of these songbird-transported ticks originate from as far south as Brazil. Clearly, passerine migrants transport ticks long distances into Canada during northward spring migration. The importation of ticks into Canada by migratory songbirds is no longer a "hypothesis," it is a fact.