1998/04/01 by Duncan J. Halley, Jan Ove Gjershaug · 35 citations
Environmental Science · Agricultural and Biological Sciences · #Avian ecology and behavior #Animal Behavior and Reproduction #Animal Ecology and Behavior Studies #Eagle #Interspecific competition #Dominance (genetics) #Carrion #Biology #Zoology #Competition (biology) #Ecology #Fishery
paper · doi:10.1111/j.1474-919x.1998.tb04392.x
published in Ibis 140(2), 295-301 (Wiley)
openalex publication_date 1998/04/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/18
The behaviour of Golden Eagles Aquila chrysaetos and Sea Eagles Haliceetus albicilla scavenging on artificially laid out carcasses in coastal Sør‐Trøndelag Province, Norway, was studied during two winters (totalling 640 h of observations) and the intervening summer (430 h). Neither species fed at carcasses in summer. Although smaller, Golden Eagles were strongly dominant over Sea Eagles in direct competition for carcass access. In Sea Eagles, females dominated males, while in Golden Eagles, few conflicts between birds of known sex were observed. Age effects were weak and not statistically significant in both species. Conflicts for carcass access tended to be most escalated between Golden Eagles and least escalated between Sea Eagles, with interspecific conflicts intermediate. Most conflicts were won by the aggressor, suggesting that birds were generally able to assess relative dominance before launching an attack. Young eagles fed longer at a carcass than older individuals in both species, suggesting that young eagles may have been hungrier or less efficient feeders. Sea Eagles waited longer than Golden Eagles between arrival in the immediate carcass area and feeding at the carcass. This effect was greater when the carcass was already occupied but also occurred when no other eagle was already present. While interspecific competition for carrion did not appear to have important consequences for the two species in coastal Norway, in western Scotland, where Sea Eagles are currently re‐establishing, carrion is important in the diet of both species all year round. Interspecific competition for this resource may therefore play a role in determining the ultimate realized niche (and therefore numbers) of the two species in Scotland in the longer term.