Evidence for birth-site tenacity in breeding Common Black-headed Gulls, Larus ridibundus

1998 ◽  
Vol 76 (12) ◽  
pp. 2295-2298 ◽  
Author(s):  
Anne-Caroline Prévot-Julliard ◽  
Roger Pradel ◽  
Jean-Dominique Lebreton ◽  
Frank Cézilly
1998 ◽  
Vol 76 (12) ◽  
pp. 2295-2298 ◽  
Author(s):  
Anne-Caroline Prévot-Julliard ◽  
Roger Pradel ◽  
Jean-Dominique Lebreton ◽  
Frank Cézilly

We show that in a large colony of Common Black-headed Gulls (Larus ridibundus) in an unstable aquatic habitat, adults that return to their natal colony tend to breed in close proximity to their natal site. We discuss this finding in relation to potential benefits from colonial nesting.


1981 ◽  
Vol 9 (3) ◽  
pp. 199-202 ◽  
Author(s):  
Malte Andersson ◽  
Frank G�tmark ◽  
Christer G. Wiklund
Keyword(s):  

1982 ◽  
Vol 60 (8) ◽  
pp. 1806-1811 ◽  
Author(s):  
Roger M. Evans

Black-billed gulls (Larus bulleri) depart form breeding colonies and foraging sites in nonrandom, clumped formations (flocks). Flocks leaving colonies were significantly smaller than those leaving foraging sites, in part owing to more "upflights" at foraging sites. When more birds left a colony per unit time, flocks were both larger and more frequent.A causal model was developed based on the assumptions that flock departures from a colony or foraging site result from the effects of social attractions superimposed on otherwise random departure intervals. This model successfully predicted the size distribution of flocks departing from four colonies and foraging sites. In conjunction with the concepts of site tenacity and habituation, the model also permits a causal explanation of differences in the size of flocks departing colonies compared with foraging sites, and of size differences in flocks arising from "upflights" as opposed to the more common "straggling" columnar formations. The model and results are consistent with the hypothesis that colonies function as assembly points that facilitate group foraging.


2012 ◽  
Vol 72 (2) ◽  
pp. 235-241 ◽  
Author(s):  
SR Posso ◽  
FB Cintra ◽  
J Frias

The foraging, territoriality and displacement of the Snail Kite were studied over 232 hours of observations in an urban lake during the dry and wet seasons. The temperature and rainfall variations were used to correlate with predation rates and the correlation coefficients were 0,39 and 0,34, respectively. Snail Kites spent more time foraging during the wet than the dry season when perching is more frequently recorded. The higher predation in the wet season can be explained by the higher abundance of apple snails and the energy demand for reproduction. In the wet season, the territories were smaller and the conspecific conflicts decreased as prey were more available. However, due to the lack of food in the dry season, intra-specific conflicts and expansion of male territories were observed and the female and immatures were expelled from their foraging area to another location. In this way, site tenacity of Snail Kites should be interpreted in relation to the variations on food and dominance gradients according to the temporal changes (time) and foraging sites (space).


2018 ◽  
Vol 13 (1) ◽  
pp. 250-252
Author(s):  
Hua Chang ◽  
Jiangqiang Han ◽  
Yan Yang ◽  
Gang Duan ◽  
Fengcai Zou ◽  
...  

AbstractChlamydiosis is an important zoonosis which can transmit from birds to humans, and investigation first reported the seroprevalence of Chlamydia psittaci in black-headed gulls (Larus ridibundus) at the Dianchi Lake, China. A total of 1029 serum samples collected from black-headed gulls between 2012-2015 were analyzed. The gulls were randomly caught and blood collected at Dianchi Lake, China. All the samples were analyzed for the presence of antibodies to C. psittaci by indirect hemagglutination assay (IHA). In this survey, the total infection rate was 11.86% (122/1029). The results of the present survey documented the existence of relatively high C. psittaci seroprevalence in black-headed gulls, which have a potential risk to the wild bird health and human health. Comprehensive practical control approaches and measures should be executed.


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