| Titre : | Journal of Avian Biology 29(1) - MAR 1998 |
| Type de document : | Bulletin |
| Paru le : | 00/00/0000 |
Dépouillements
Article
G. A. Gudmundsson, Auteur ;
T. Alerstam, Auteur
Tracking radar studies mere carried out during the summer 1996 in the central polar basin (85-90 degrees N) to investigate if birds accomplish transpolar migration. We here report the absence of bird migration from this region, in glaring contra[...]
Article
K. Norrdahl, Auteur ;
E. Korpimäki, Auteur
The abundances of potential avian prey species may be lower in the vicinity of the nests of predatory birds than farther away. We predicted that, if this density depression is due to predation, the observed density pattern should develop gradual[...]
Article
B. J. M. Stutchbury, Auteur ;
E. S. Morton, Auteur ;
W. H. Piper, Auteur
Extra-pair matings are now recognized as a fundamental component of avian mating systems. However, in tropical regions where breeding is typically asynchronous socially monogamous species appear to have low sperm competition and few extrapair ma[...]
Article
I. Krams, Auteur
A bird foraging al concentrated food sources such as artificial feeders or carcasses of wild animals. irrespective of its dominance rank, may be preyed upon by airborne predators with a greater probability than other flock members foraging under[...]
Article
J. T. Forsman, Auteur ;
M. Monkkonen, Auteur ;
J. Inkeroinen, Auteur ;
P. Reunanen, Auteur
Animals may join flocks to gain protection against predation. In this experiment we investigated how predation risk affects the spatial distribution of forest birds during breeding time. We manipulated the perceived risk of predation by showing [...]
Article
P. Galeotti, Auteur
The patterned hooting of owls may serve one or more functions including repulsion of territorial invaders, attraction of potential mates, and stimulation of the mate. In this study I looked For characteristics in the Tawny Owl hoot which might c[...]
Article
G. E. Hill, Auteur
The redness of carotenoid pigmentation has been shown to be an indicator of individual condition. I tested whether the asymmetry of carotenoid pigmentation of male House Finches Carpodacus mexicanus, an indicator of developmental stability, decr[...]
Article
D. Csermely, Auteur ;
L. Berte, Auteur ;
R. Camoni, Auteur
The technique used by birds of prey to kill their quarry has rarely been described in detail. Although it is common to watch a raptor hunting, distance and natural obstacles normally prevent the observer from observing what actually happens to t[...]
Article
M. A. Jurisevic, Auteur ;
K. J. Sanderson, Auteur
Distress vocalisations were recorded from 65 species of Australian birds, including passerines, parrots and raptors while held in the hand or entangled in mistnets. Distress vocalisations were shown to have similar structural properties in many [...]
Article
K. E. Erikstad, Auteur ;
T. Tveraa, Auteur ;
J. O. Bustnes, Auteur
In ducks and geese intraclutch egg-size variation shows a consistent pattern. The first egg is generally smaller than the second egg and from then on egg size declines over the laying sequence. Such an intraclutch egg-size pattern has previously[...]
Article
S. Wanless, Auteur ;
D. Gremillet, Auteur ;
M. P. Harris, Auteur
We combined radiotelemetry techniques with an automatic nest balance system to obtain detailed, concurrent data on foraging activity, prey consumption and foraging performance in four pairs of Shags Phalacrocorax aristotelis during chick rearing[...]
Article
The classical theory of cross-country soaring flight postulates climbs in discrete thermals, separated by glides through stationary air, and prescribes an "optimum" speed for the inter-thermal glides, based on the performance of the glider or bi[...]
Article
T. Hino, Auteur
I examined the feeding rates and foraging niches of seven species regularly participating in heterospecific avian flocks in a deciduous dry forest of western Madagascar in two different social situations, viz. when the species was foraging alone[...]
