. The Canadian field-naturalist. Figure 1. A typical roost of shorebirds (mainly Semipalmated Sandpipers) at Evangeline Beach, Nova Scotia, 30 July 1991, showing location of m- quadrat. Photo by J. Deal. Traditional roosting sites along Evangeline Beach were identified, and distances between landmarks (, property lines, flag poles, etc.) along the shore- line were measured. The roosts were typically square or rectangular (Figure 1), and we noted the land- marks along the edges of the roost. The area occu- pied by each roost was calculated in m^ and multi- plied by the density of the sh
. The Canadian field-naturalist. Figure 1. A typical roost of shorebirds (mainly Semipalmated Sandpipers) at Evangeline Beach, Nova Scotia, 30 July 1991, showing location of m- quadrat. Photo by J. Deal. Traditional roosting sites along Evangeline Beach were identified, and distances between landmarks (, property lines, flag poles, etc.) along the shore- line were measured. The roosts were typically square or rectangular (Figure 1), and we noted the land- marks along the edges of the roost. The area occu- pied by each roost was calculated in m^ and multi- plied by the density of the shorebirds per m-, obtained from the photographs, to provide an esti- mate of the numbers of roosting birds. Results In six photographs examined, the mean number of shorebirds was 82/m- ± (N=6), ranging from 57 (Figure 2) to a maximum of 101 birds/m^ (Figure 2c). However, the avoidance of the con- spicuously marked quadrat is evident in all three photographs (Figures 2, 3, 4, and personal observa- tion) and the density of 57 birds/m^ was unrepre- sentative of the main flock. The higher densities of the roost not impinging on the marked quadrat (Figures 3 and 4) suggest that 82 birds/m- was a minimum estimate of density (, a loosely packed roost ) whereas 100 birds/m- was more nearly rep- resentative of the roost as a whole (Figure 4; and personal observation). Hence, Hicklin's earlier (1987) estimate of 60 birds/m^ was an underesti- mate. This new mean and maximum represents increases of 37-67% in the numbers of roosting birds per m^ compared to those of Hicklin (1987). Using this method, the number of roosting birds in a single roost occupying 1299 m- at Evangeline Beach 30 July 1991 was estimated to be 131 200 shorebirds at 101 birds/m^ (Figure 1). Hicklin (1987) calculated the population of Semipalmated Sandpipers migrating through the upper Bay of Fundy by adding up the average peak numbers of adults and immatures for each roost site (including miscellaneous sma
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