Reproductive Success of Eurasian Eagle-Owls in Wetland and Non-wetland Habitats of West-central Korea
2016
Shin, Dong-Man | Yoo, Jeong-Chil
The breeding success of raptors is strongly affected by food supply. We examined the reproductive success of Eurasian Eagle-Owls (Bubo bubo) and assessed the effects of landscape and diet on reproductive success at 44 nest sites in wetland and non-wetland (mostly agricultural lands, forests, and human settlements) habitats in west-central Korea. We found that eagle-owl reproductive success was significantly higher in wetland than in non-wetland habitats (mean of 1.9 vs. 1.3 fledglings per breeding pair, respectively). Although the average number of fledglings per successful pair was similar in the two habitats (2.0 vs. 1.8), the average numbers of fledglings per hatchling (0.9 vs. 0.7) and per egg (0.8 vs. 0.5) were both higher in wetland habitats. Further, for the wetland habitats, birds (mostly Anatidae, Columbidae, and Phasianidae) were the most important prey group by both number and biomass (67% and 84%, respectively) in the breeding period. However, in non-wetland habitats, both mammals (59% by number) and birds (67% by biomass) were important prey in the breeding period. The amount of Phasianidae in the diet (by biomass) and the date of the onset of egg-laying were positively and negatively (respectively) significant determinants of the number of fledglings per egg, whereas the percentage of wetland in the habitat was the only significant determinant for the number of fledglings per hatchling.
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