@misc{Randler_Christoph_Aggressive_2004,
 author={Randler, Christoph and Polska Akademia Nauk. Muzeum i Instytut Zoologii},
 editor={Museum and Institute of Zoology, Polish Academy of Sciences},
 copyright={Rights Reserved - Free Access},
 address={Warszawa},
 howpublished={online},
 year={2004},
 language={eng},
 abstract={Evidence for direct interspecific competition in wildfowl and between hybrids and their parent speciesis scarce. This study examined threat displays and agonistic encounters (n = 324) in a goose flock of 140 SwanGeese and 13 hybrids with Greylag Goose living in Heidelberg, SW Germany. In general, agonistic behaviourmade up less than 1% of the time budget throughout the year as measured by focal animal sampling. Mostencounters (84%) were won by the initiator, both in Swan Geese and in hybrids. No difference was found betweenSwan Geese and hybrids in the outcome of an encounter, suggesting equal competitive quality. There were differenceswith respect to threat postures with hybrids performing diagonal neck threats more often and intentionalmovements less often. This seems to be related to their hybrid origin, since Greylag Geese most often showdiagonal neck and forward threat displays. There was no direct evidence for hybrid superiority or inferiority},
 type={Text},
 title={Aggressive interactions in swan geese Anser cygnoides and their hybrids},
 volume={39},
 number={2},
 journal={Acta Ornithologica},
 publisher={Museum & Institute of Zoology},
 keywords={Swan Goose, Anser cygnoides, Greylag Goose, Anser anser, aggressive behaviour, foraging, hybridsuperiority, competition, threat postures, wildfowl},
}