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Regular surveys of Great Blue Heron (Ardea herodias) colonies in Quebec, conducted between 1977 and 2001, resulted in the discovery of 705 colonies, mostly in the western part of the province. While single breeding pairs were occasionally found (9% of Quebec "heronries"), the colonies were generally composed of fewer than 16 breeding pairs, with sometimes over 50 (18 known colonies), as was the case on several islands in the St. Lawrence River. Close to one-third (1919 of the 6481 active nests) of the Quebec Great Blue Heron population was associated with heronries in the St. Lawrence system. Half of the St. Lawrence heronries that were active during two adjacent survey periods (1975-1983 and 1984-1990, or 1984-1990 and 1991-2001) increased in size between periods, while one-third of the colonies decreased in size. One-sixth of the colonies remained the same size during the study period. Great Blue Herons periodically abandon their colonies and settle elsewhere. Our data show that 50% of known Quebec colonies (n = 377 colonies visited more than once) were abandoned after being discovered as active colonies, and, on average, all nests in colonies that are abandoned disappear 7 years after discovery of the colony. On the basis of thorough inventories conducted on the St. Lawrence, we found that all nest platforms in 14 of the 70 colony sites had disappeared in less than 25 years. Since 1977, when regular surveys began, 50-90% of breeding attempts have been successful, yielding an average of over 2.2 chicks per pair. This productivity rate suggests that the Quebec population of Great Blue Herons may be increasing and may explain the recent expansion in its range. Following our 25 years of investigation on the Great Blue Heron in the province, we estimate the current late-summer Great Blue Heron population of Quebec at some 27 000 individuals (6500 pairs producing 2.2 young per pair per year).--Publisher's description.
Describes the characteristics, abundance and condition of vegetation communities within and around the lesser snow goose colony and examines the effects of the colony on the abundance of breeding shorebirds and songbirds.
Describes key terrestrial habitat areas that are essential to the welfare of various migratory bird species in Canada.
"We estimated that 264 000-452 000 Lesser Snow Geese Chen caerulescens caerulescens nested at Egg Riveron Banks Island, Northwest Territories, in 1995-1998. This was about twice as many geese as was reported nesting there in the 1980s, and we estimated that the nesting population grew by 4.2% per year from 1953 to 1998"--Abstract.
Current Ornithology publishes authoritative, up-to-date, scholarly reviews of topics selected from the full range of current research in avian biology. Topics cover the spectrum from the molecular level of organization to population biology and community ecology. The series seeks especially to review (1) fields in which an abundant recent literature will benefit from synthesis and organization, or (2) newly emerging fields that are gaining recognition as the result of recent discoveries or shifts in perspective, or (3) fields in which students of vertebrates may benefit from comparisons of birds with other classes. All chapters are invited, and authors are chosen for their leadership in the subjects under review.
This volume represents a first attempt at holistically classifying and mapping ecological regions across all three countries of the North American continent. A common analytical methodology is used to examine North American ecology at multiple scales, from large continental ecosystems to subdivisions of these that correlate more detailed physical and biological settings with human activities on two levels of successively smaller units. The volume begins with an overview of North America from an ecological perspective, concepts of ecological regionalization. This is followed by descriptions of the 15 broad ecological regions, including information on physical and biological setting and human activities. The final section presents case studies in applications of the ecological characterization methodology to environmental issues. The appendix includes a list of common and scientific names of selected species characteristic of the ecological regions.