Breeding Ecology Of Hooded Crow (corvus Cornix L.) Populations In Transformed Landscapes
ÃÂ. ÃÂ. Zimaroyeva, ÃÂ. V. Matsyura
The comparative analysis of hooded crow breeding ecology was performed for Zhitomir region in 2010-2011 in terms of rural and urban distinctions. Height of trees, tree species diversity in breeding biotopes, nest size, and breeding success of hooded crows were considered for agricultural and urban landscapes. Definite patterns of breeding ecology were estimated for urban and rural populations of hooded crows. On average, the breeding density of hooded crows was 7-8 individuals/km2 in Zhitomir region. Positive correlation was found between the breeding density of hooded crows and degree of transformation and urbanization of landscape of Zhytomyr region. The main breeding habitats of hooded crows in the Zhitomir region were the wetland sites. Communities of urban birds were characterized by earlier terms of nest building, more higher position of nests in the trees and high diversity of tree breeding habitats. In urbanized landscape we determined high proportion of large (6 eggs) and small clutches of hooded crow (3 eggs). On average the breeding success of crows in Zhytomyr region is 51.1%. We suggested that the main factor was high level of elimination of embryos and chicks of hooded crow. In urbanized landscapes the breeding success (50%) is somewhat higher than that in rural areas (43.5%). This can be explained by specific features of ecological niches - in cities the bird communities have few natural predators that kill chicks and destroy clutches, and potentially have more available food resources.