TY - JOUR

T1 - Occurrence and behaviour of White-tailed Sea Eagles Haliaeetus albicilla in Great Cormorant Phalacrocorax carbo sinensis colonies in countries around the Baltic Sea

AU - Bregnballe, Thomas

AU - Tofft, Jesper

AU - Kotzerka, Jana

AU - Lehikoinen, Aleksi

AU - Rusanen, Pekka

AU - Herrmann, Christof

AU - Krone, Oliver

AU - Engström, Henri

AU - Rattiste, Kalev

AU - Reich, Jürgen

AU - Kouzov, Sergey A.

N1 - Bregnballe T., Tofft J., Kotzerka J., Lehikoinen A., Rusanen P., Herrmann C.,Krone O., Engström H., Rattiste K., Reich J. & Kouzov S.A. 2021. Occurrenceand behaviour of White-tailed Eagles Haliaeetus albicilla in Great CormorantPhalacrocorax carbo sinensis colonies in countries around the Baltic Sea.Ardea 109: 565–582. doi:10.5253/arde.v109i2.a24

PY - 2022

Y1 - 2022

N2 - The recovery of the Baltic White-tailed Eagle Haliaeetus albicilla population since the 1980s is a conservation success story. However, the re-establishment of this predator in coastal and lake areas appears to affect Great Cormorants Phalacrocorax carbo during the breeding season. We collated published and unpublished records of White-tailed Eagle occurrence and interactions with Cormorant colonies as well as records of Cormorant anti-predator responses and effects on Cormorant breeding performance. We found evidence for immediate direct effects (mainly kleptoparasitism, predation of eggs and offspring) and indirect effects (facilitating nest predation by mainly gulls and corvids). Repeated disturbance from hunting White-tailed Eagles was also inferred to trigger changes in selection of nest sites, to cause complete abandonment of colonies and lead to regional redistributions of breeders. However, there are also observations of unproblematic coexistence with White-tailed Eagles breeding inside Cormorant colonies. There is some evidence to suggest that nesting opportunities for Cormorants may become further restricted as White-tailed Eagle numbers continue to increase, and we argue that this in some regions will impose limitations on the distribution and size of breeding populations of Cormorants.

AB - The recovery of the Baltic White-tailed Eagle Haliaeetus albicilla population since the 1980s is a conservation success story. However, the re-establishment of this predator in coastal and lake areas appears to affect Great Cormorants Phalacrocorax carbo during the breeding season. We collated published and unpublished records of White-tailed Eagle occurrence and interactions with Cormorant colonies as well as records of Cormorant anti-predator responses and effects on Cormorant breeding performance. We found evidence for immediate direct effects (mainly kleptoparasitism, predation of eggs and offspring) and indirect effects (facilitating nest predation by mainly gulls and corvids). Repeated disturbance from hunting White-tailed Eagles was also inferred to trigger changes in selection of nest sites, to cause complete abandonment of colonies and lead to regional redistributions of breeders. However, there are also observations of unproblematic coexistence with White-tailed Eagles breeding inside Cormorant colonies. There is some evidence to suggest that nesting opportunities for Cormorants may become further restricted as White-tailed Eagle numbers continue to increase, and we argue that this in some regions will impose limitations on the distribution and size of breeding populations of Cormorants.

KW - adaptation

KW - behaviour

KW - breeding success

KW - colonies

KW - disturbance

KW - indirect effects

KW - nest predation

UR - https://www.researchgate.net/publication/361796854_Occurrence_and_Behaviour_of_White-Tailed_Eagles_Haliaeetus_albicilla_in_Great_Cormorant_Phalacrocorax_Carbo_Sinensis_Colonies_in_Countries_around_the_Baltic_Sea

UR - https://helda.helsinki.fi/handle/10138/346610?show=full

M3 - Article

VL - 109

SP - 565

EP - 582

JO - Ardea

JF - Ardea

SN - 0373-2266

IS - 3

ER -