Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 7

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  Corvus cornix
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
The species composition of the Hooded Crow (Corvus cornix) prey and its preferences for selected bird species are described on the basis of the egg shells found in the flooded area in the National Park “Ujście Warty” in Western Poland. In the years 2000–2003, during breeding seasons, 1104 shells of 16 bird species were found. The most common species was the Coot Fulica atra (69% of all the shells). The remaining species mainly were: the Mallard Anas platyrhynchos (13%), the Black-headed Gull Larus ridibundus (7%), the Black-necked Grebe Podiceps nigricollis (4%) and the Garganey Anas querquedula (4%). The number of shells found and the median date when shells were found differed between the years of study. The differences are probably related to the effect of variation in the number and differences in breeding phenology of potential crow’s prey between seasons, which are connected with water conditions occurring in the study area.
Rooks show a growing tendency to winter in cities. The aim of this study was to determine the influence of meteorological factors on the selection of feeding habitats and to discuss the diversity of feeding strategies in urban environments of different sizes and housing densities. The study was carried out in two cities in south-western Poland, Wrocław and Brzeg (populations of 636,000 and 39,000, respectively), in the years 2004–2008. Nineteen research areas differing in housing density were controlled once a week. In multiple regression, the number of rooks feeding in urban environments showed a correlation with air temperature and the thickness of snow cover. The densities of feeding rooks were higher in urban environments than in agrocenoses. They were also higher in Wrocław than in Brzeg, and in built-up areas than in undeveloped ones. Feeding groups were smaller in Brzeg than in Wrocław. They were also smaller in built-up areas in Brzeg than in undeveloped ones. More rooks fed individually in Brzeg than in Wrocław. The diversity in the frequency of individually feeding rooks in built-up and undeveloped environments was specific to each city. Rooks feeding in Brzeg were more active in searching for food than those in Wrocław, and birds feeding on optimum, undeveloped feeding grounds were more active than those in built-up areas . In both cities, rooks were fed by humans, mainly in built-up areas.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.