Great Cormorant (Phalacrocorax carbo) Science Article 20 abstract The habit of mass fishing by Cormorants at lake IJsselmeer, The Netherlands, is a recent phenomenon. During the first half of the 1970s the birds changed behaviour probably as a result of the deteriorating under water visibility in the take (3-4 m water depth). The behavioural switch […]
Tag: Phalacrocorax carbo
Individual migration strategies in Cormorants Phalacrocorax carbo passing through or wintering in western France.
Great Cormorant (Phalacrocorax carbo) Science Article 16 abstract The attendance of individually recognisable Cormorants has been studied at a roost site in western France together with the overall use of this roost. Only first and second year birds arrived at the roost before mid-October and almost only 1st-year birds did so after February. In the […]
Are Cormorants Phalacrocorax carbo wintering in Switzerland approaching carrying capacity? An analysis of increase patterns and habitat choice.
Great Cormorant (Phalacrocorax carbo) Science Article 17 abstract The increase rate of Cormorant numbers overwintering in Switzerland between 1970 and 1990 was the same as in the strongly growing breeding population. From 1930 to 1970, however, wintering Cormorants increased while the breeding population remained stable. The reasons are believed to be a better food supply […]
Time and energy constraints of fishing behaviour in breeding Cormorants Phalacrocorax carbo sinensis at lake Ijsselmeer, The Netherlands.
Great Cormorant (Phalacrocorax carbo) Science Article 18 abstract Two Cormorant colonies in The Netherlands (Naardermeer and Oostvaardersplassen), exploiting the same water bodies but situated at different distances from them, were compared with respect to daily variations in exact fishing sites and corresponding variations in time budget and fish consumption. Mean flying distances between colony and […]
Roach rules: Shoaling fish are a constant factor in the diet of Cormorants Phalacrocorax carbox in Switzerland
Great Cormorant (Phalacrocorax carbo) Science Article 29 abstract The spatial and temporal variation in the diet of Cormorants Phalacrocorax carbo visiting Switzerland in the non-breeding season was studied from 1985-1992, by means of regurgitated pellets and stomach contents. The results, combined with the data of most other dietary studies from Switzerland since 1974, rest on […]
Food of Cormorants Phalacrocorax carbo sinensis wintering in Bavaria, southern Germany.
Great Cormorant (Phalacrocorax carbo) Science Article 21 abstract Following the spectacular population increase in continental Cormorants, numbers of wintering birds on lakes and rivers in Bavaria, southern Germany, have risen sharply. Because of a growing concern among commercial fishermen and anglers, a diet study has been carried out at two major roosts: one at a […]
Status distribution and habitat use by Cormorants Phalacrocorax carbo wintering in Britain
Great Cormorant (Phalacrocorax carbo) Science Article 25 abstract This paper describes a study of Cormorants wintering in Britain based on information collected as part of the National Waterfowl Counts scheme for the four winter seasons from 1987/88 to 1990/91. Birds were found to be widely distributed throughout Britain, both inland and on the coast, with […]
Changes in abundance of cyprinid and percid prey affect rate of predation by Cormorants Phalacrocorax carbo carbo on Salmon Salmo salar smolt in northern Ireland
Great Cormorant (Phalacrocorax carbo) Science Article 23 abstract Cormorant diet is described from the analysis of pellets, fledgling regurgitates and the stomach contents of adult birds. Non-breeding coastal birds consumed mostly marine fish while breeding birds were found to feed mostly on freshwater fish species. The long distances travelled to inland feeding sites while breeding […]
The telltale heart: A non-invasive method to determine the energy expenditure of incubating Great Cormorants Phalacrocorax carbo carbo.
Great Cormorant (Phalacrocorax carbo) Science Article 31 abstract We studied the energetics of incubating Great Cormorants Phalacrocorax carbo carbo via heart rate and respirometric measurements performed in captive and free-living animals. We applied a modified heart beat frequency (HR) monitor built for use in human athletics as well as respirometry for measurements in four captive-bred […]
Sub-specific differentiation and distribution of Great Cormorants Phalacrocorax carbo in Europe
Great Cormorant (Phalacrocorax carbo) Science Article 1 abstract The use of biometrics for sub-specific differentiation of Great Cormorants Phalacrocorax carbo in Europe was investigated using skins of known subspecies and showed that gular pouch angle is a useful character for assigning individuals to sub-species. Where further measurements of bill depth and bill length can be […]