. The Canadian field-naturalist. 1980 RENAUD and BRADSTREET: BLACK GUILLEMOTS, CANADIAN ARCTIC 423. Figure 2. Survey routes in northwest Baffin Bay and numbers of guillemots seen. over pack ice containing many cracks and leads. The polynias surveyed during 1977 and 1978 were also heavily covered by drift ice, and open water was confined to small cracks and holes. It is probable that many of these polynias are intermittent and com- pletely freeze over during some winters, and for short periods during other winters. Results Black Guillemots were seen in only two polynias in 1977 and 1978: 15 wer
. The Canadian field-naturalist. 1980 RENAUD and BRADSTREET: BLACK GUILLEMOTS, CANADIAN ARCTIC 423. Figure 2. Survey routes in northwest Baffin Bay and numbers of guillemots seen. over pack ice containing many cracks and leads. The polynias surveyed during 1977 and 1978 were also heavily covered by drift ice, and open water was confined to small cracks and holes. It is probable that many of these polynias are intermittent and com- pletely freeze over during some winters, and for short periods during other winters. Results Black Guillemots were seen in only two polynias in 1977 and 1978: 15 were seen north of Dundas Island on 19 April 1977, and 6 were observed in Hell Gate and Cardigan Strait on 17 March 1978 (Figure 1). A total of 2376 guillemots was seen during three surveys of the northwest Baffin Bay area in 1978 and 1979 (Figure 2). Concentrations were greatest in leads along, or near, landfast ice edges. Mean densities of guillemots along the ice edges surveyed in March 1978 ( birds/km) and March 1979 ( birds/km) were similar {P> ). The largest concentrations seen dur- ing March were along ice edges off eastern Devon Island (1978; not surveyed in 1979); in eastern Jones Sound and southwestern Glacier Strait (1978; only partially surveyed in 1979); and in southeastern and eastern Glacier Strait (1978 and especially 1979). In 1978, densities along ice edges declined significantly between March () and April () (P<). Densities offshore in northern Baffin Bay were sim- ilar during March and April of 1978 ( vs. ; P = ); densities offshore in March 1978 and March 1979 ( and ) were also similar {P = ). The overall mean density of guillemots on transects over pack ice in March and April 1978 () suggests that about 3900 guillemots were present in about 23 000 km- of pack ice habitat avail- able between the transect line from Cape Parry to Glacier Strait and the ice edge across northern Smith Sound.
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