McIntosh, Lorne Douglas2024-08-142024-08-1419851985https://hdl.handle.net/1828/18934Data from 1850 ten-minute observation periods, recorded during six oceanographic voyages off Canada's west coast between October 1981 and October 1983, are analyzed in an attempt to determine relationships of observed seabird numbers to season, weather, salinity, temperature and distance offshore. Chi-square analyses indicate a significant relationship exists between observed presence/absence of seabirds and season for sooty shearwaters, albatrosses, alcids, large gulls, storm-petrels and black-legged kittiwakes. The same technique also reveals a significant relationship between observed presence/absence of birds and weather for all species groups except storm-petrels. Calculation of Spearman's coefficient of correlation between salinity, temperature, and distance offshore and observed numbers of birds gives no indication of a general trend although certain species groups were significantly correlated to one or more environmental variables at different times of year. Leach's and fork-tailed storm-petrels, combined as storm-petrels, show no correlation with any of the selected variables. The albatross species group, mainly black-footed albatrosses, are significantly correlated only with temperature in March 1982. Tests of distances to which small floating targets (simulating seabirds) remain visible after discharge from a departing ship suggest that target size, gray tone (or colour), and presence of white caps are significant sources of variation. Variations in these observability distances bias estimates of seabird populations towards higher estimates for large, light toned birds observed during calm conditions. Future work towards solution of this problem, possibly by determination of an observability coefficient for each species, is recommended.126 pagesAvailable to the World Wide WebThesis