A re-evaluation of the numbers of migrant Semipalmated Sandpipers, Calidris pusilla, in the Bay of Fundy during fall migration

Abstract

We improved on the methodology to quantify the numbers of shorebirds in large roosts in the Bay of Fundy during fall migration. A series of photographs was taken of a large roost of Semipalmated Sandpipers where a 1 m2 quadrat had been placed. The number of sandpipers inside the quadrat was counted from photographs to provide a measure of roosting density (/m2) in a 1) loose or 2) compact flock, which was extrapolated to the area of the roost (in m2). Our findings represent a 37-67% increase in the density figures, and our recalculation of the total numbers of shorebirds in the Bay of Fundy, is 1 122 000 to 2 200 000, as opposed to the earlier estimate of 800 000 to 1 400 000 birds.