Molecular Genetic (RAPD) Analysis of Leach's Storm-Petrels

Abstract

Leach's Storm-Petrels (Oceanodroma leucorhoa) breed colonially on islands off the Atlantic coast of Canada and exhibit strong site and mate fidelity. We used RAPD mark- ers to estimate relationships among 91 petrels representing three colonies: Bon Portage Is- land and Big White Island in Nova Scotia, and Gull Island in Newfoundland. Analysis of molecular variance indicated small but significant variance among groups (2.53% for Nova Scotia vs. Newfoundland) and among colonies within groups (2.58% among the three nest- ing islands). Neighbor-joining dendrograms using similarity and percent match metrics failed to recover colonial groupings. The observed genetic structure probably is due to a historical association during the most recent glaciation or is a result of barriers that impede genetic mixing. Received 19 November 1997, accepted 23 July 1998. LEACH'S STORM-PETRELS (Oceanodroma leu- corhoa) breed on islands throughout the North- ern Hemisphere. Their main breeding range in the western Atlantic extends from Maine to Newfoundland, where their numbers have been estimated in the millions (Cairns et al. 1989). Leach's Storm-Petrels nest in burrows on offshore islands that are devoid of mammalian predators. They are one of the smallest seabirds in the North Atlantic and are active on land only at night, returning to sea before first light or remaining in the burrow during the day. Fe- males lay a single egg each breeding season and seldom relay if this egg fails to hatch. Mat- ed pairs share incubation and rearing duties. Leach's Storm-Petrels are long lived (>36