Dispersal patterns suggest two breeding populations of piping plovers in Eastern Canada

Piping Plovers (Charadrius m. melodus) were banded in eastern Canada, in the Gulf of St. Lawrence (Gulf) region, including the Magdalen Islands (Québec), New Brunswick, Newfoundland, northern Nova Scotia and Prince Edward Island, and the southern Nova Scotia (sNS) region from 1998-2003, and recaptured and/or resighted from 1999-2007. Return rates of banded individuals were greater for adults than juvenile birds, likely reflecting the higher survival and site fidelity of this age class. The best-fit model explaining differences in annual dispersal distance included age class (P < 0.001), region (P = 0.004) and the interaction of age class and region (P = 0.074). Juvenile dispersal movements in the Gulf (median: 28.0 km, range: 0.4-306.3 km) were greater than in sNS (median: 18.6 km, range: 6.5-74.8 km), but adult movements in sNS (median: 4.0 km, range: 0.01-70.7 km) were greater than in the Gulf (median: 0.5 km, range: 0.01-298.6 km). While some annual dispersal movements in the Gulf were large enough to cover the distance between both regions (>225 km), these movements only represented 1% of all observations and none involved movements between the Gulf and sNS. The lack of movement between regions, and previous studies documenting differences in population dynamics and habitat use, suggests that two distinct breeding populations of Piping Plovers exist in eastern Canada. Future management of the species should consider the distinct conservation needs of both populations and recognize that local efforts may not result in regional population increases because of small dispersal distances in eastern Canada, and, potentially, in other populations in North America. At this time, the small sNS population may be particularly vulnerable to extirpation, as the potential for dispersal from nearby populations appears limited.