The Breeding Distribution, History and Population of the North Atlantic Gannet (Sula bassana) [reprinted from Journal of Animal Ecology, v12 n2, pages 173-213]

James Fisher; H G Vevers

Verlag: Journal of Animal Ecology, 1943

Beschreibung

Journal of Animal Ecology, v12 n2, pages 173-213. Abstract: 1. In 1939 an attempt to make a census, within the space of one breeding season, of the world population of the gannet (Sula bassana L.), was organized by the writers. 2. In 1939 gannets were breeding at 22 colonies. Three of these were in south-west Britain, 2 in east Britain, 2 in west Britain, 6 in north Britain and the Faeroes, 3 in Iceland and 6 in the Gulf of St Lawrence. Of these, all the colonies in Britain, the Faeroes and Iceland were visited in 1939. Of the colonies in the Gulf of St Lawrence 2 were visited in 1939, 1 in 1940, 1 in 1941 (not having been discovered previously) and 2 for the last time in 1934 and 1936. The colonies not visited in 1939 contained about 2.5% of the world population. 3. The history of the 39 places where gannets breed, have bred, have been suspected to have bred, or have occupied cliffs or ledges in the breeding season is fully discussed, as are the results of the 1939 census. A summary is provided in Table 4. All save 6 which are of doubtful or vague history are shown on Map 5. 4. The number of breeding individuals of Sula bassana in 1939 was 165,600 +- 9500. The limits of error were worked out from a sample of over half the population, which was breeding at colonies where more than one observer took part in the census, and represent the maximum recorded discrepancy between the counts of the different observers of each group of nests in the colonies. 5. A full discussion of trends in the gannet's population during the last hundred years, and of certain ecological points and biological matters which arise from this survey, is reserved for Part 2 of this paper. Bestandsnummer des Verkäufers 2ewgore924

Bibliografische Details

Titel: The Breeding Distribution, History and ...

Verlag: Journal of Animal Ecology

Erscheinungsdatum: 1943

Einband: Soft cover

Zustand: Good

Signiert: Inscribed by Author(s)

Auflage: 1st Edition