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THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 1, March 2011 
The Wilson Journal of Ornithology 123(1): 174-176, 2011 
Adoptions of Young Common Buzzards in White-tailed Sea Eagle Nests 
Ivan Literak 1,3 and Jakub Mraz 2 
ABSTRACT.—Documentation of interspecific adop¬ 
tion of young is rare in the published literature among 
birds. We survey six cases of young Common Buzzards 
(Buteo buteo) adopted in nests of White-tailed Sea 
Eagle (Haliaeetus albicilla) in central Europe (Czech 
Republic and Hungary). Common Buzzard nestlings 
adopted were in good condition and adult White-tailed 
Sea Eagles fed and cared for them properly. Young 
Common Buzzards successfully hedged and left the 
White-tailed Sea Eagle nests. The most probable 
explanation of this phenomenon is a non-lethal 
predation of Common Buzzards followed by White¬ 
tailed Sea Eagle parental care as a result of parental 
recognition error. Similar cases of adoption of Red¬ 
tailed Hawk (Buteo jamaicensis) nestlings in nests of 
Bald Eagle (Haliaeetus leucocephalus) have been 
documented in North America. Received 17 May 
2010. Accepted 27 July 2010. 
Adoption is defined in the ornithological litera¬ 
ture as caregiving to young or eggs by unrelated 
adults but interspecific adoption has rarely been 
reported (Capek et al. 2000). Repeated cases of the 
same type of interspecific adoption have been 
described only in nesting Bald Eagles (Haliaeetus 
leucocephalus) in North America which adopted 
young Red-tailed Hawks (Buteo jamaicensis) 
(Stefanek et al. 1992, Watson et al. 1993, Watson 
and Cunningham 1996). We observed adoption of a 
Common Buzzard ( B. buteo) nestling in a White¬ 
tailed Sea Eagle (H. albicilla) nest in the Czech 
Republic in 2007. In addition, we found notes about 
other such cases in the Czech Republic and 
Hungary in the local literature, suggesting this type 
of interspecific adoption by raptors is probably 
more frequent in central Europe then we had 
supposed. We report cases of adoptions of young 
Common Buzzards by nesting White-tailed Sea 
Eagles and speculate on possible explanations for 
this phenomenon. 
'Department of Biology and Wildlife Diseases, Faculty 
of Veterinary Hygiene and Ecology, University of Veter¬ 
inary and Pharmaceutical Sciences, Palackeho 1-3, 612 42 
Brno, Czech Republic. 
* Dvorecka 264, 37901 Brilice-Trebon, Czech Republic. 
Corresponding author: e-mail: literaki@vfu.cz 
OBSERVATIONS 
We originally observed a young Common 
Buzzard reared in a nest of White-tailed Sea 
Eagles near the village of Hrachoviste, southwest¬ 
ern Czech Republic (48° 55' N, 14° 46' E). The 
nest was in a forest close to a clearing and was 
built on a Scots Pine (Pinus sylvestris) tree at a 
height of ~20 m. The nest was checked by the 
second author on 20 May 2007 to see if the young 
eagles were at an age suitable for ringing. There 
were two eagles ~3 weeks of age and, surpris¬ 
ingly, also a live Common Buzzard chick 
~2 weeks of age. All young were in good 
condition. Adult eagles were flying above the 
nest and an adult Common Buzzard also was 
observed flying above the nest but it was not 
evident whether this individual could be a parent 
of the young buzzard in the eagle nest. The nest 
was checked again on 12 June 2007 during which 
time the young buzzard had already fledged and 
was sitting in a tree at a distance of ~ 150 m. The 
two young eagles (~6 weeks of age) stayed on 
the nest. This proved that adult White-tailed Sea 
Eagles from this nest had adopted a young 
Common Buzzard and cared for it during a period 
of at least ~3 weeks. No adult Common Buzzard 
was observed near the nest during the second visit. 
The second author personally checked 21 nests ot 
White-tailed Sea Eagles in the Czech Republic 
and found a young Common Buzzard only in the 
nest described. 
DISCUSSION 
A young Common Buzzard was observed in 
2000 by P. Kurka in the nest of a White-tailed Sea 
Eagle in the northern part of the Czech Republic 
(Schropfer 2002). P. Kurka was checking the nest 
on a pine tree on 4 June 2000 and found one young 
White-tailed Sea Eagle and one young Common 
Buzzard both alive, as well as two dead young 
Common Buzzards ~1 week of age. No more 
information is available for this case. A nest of 
White-tailed Sea Eagles with two Common Buz¬ 
zard chicks of different ages plus a White-tailed Sea 
Eagle nestling was found in Hungary in 2007 
