Analysis of anthropogenic tolerance of corvids in Zhytomyr urban habitats

Abstract

The results of studies of anthropogenic tolerance of corvids were performed in Zhytomyr from September 2009 to August 2012. We have chosen the Rook (Corvus frugilegus L.), Western Jackdaw (Corvus monedula L.), and Hooded Crow (Corvus cornix L.) as model species. The take-off was basic locomotory reaction of bird species towards human disturbance. The back track or jamp-off from human trajectory were observed for 22.9% of Hooded Crows, 26.8% of Western Jackdaws, and 29.7% of Rooks. We registered that the average flight initiation distance and back track distance were not significant (p>0.05) for Rooks (p = 0.72, Mann-Whitney U = 16882), Hooded Crows (p = 0.90, U = 2521.5) and Western Jackdaws (p = 0.57; U = 21). We tested that flight initiation distance of Rooks varied from 0.5 to 21.5 m, Western Jackdaws – from 0.8 to 19 m, Hooded Crows – from 0.5 to 16.3 m. We suggested that degree of bird tolerance to anthropogenic disturbance in urban habitats depends on the intensity of anthropogenic pressure. We found the inverse correlation between flight initiation distance and degree of anthropogenic transformation of the landscape. The main factors which determine the flight initiation distance, were the type of habitat (the most significant factor), the number of birds in the group, direction and parameters of human impact, and year season.

Keywords

• zhytomyr oblast
• urban habitat
• corvids
• birds
• adaptation
• synantropi­zation
• antropogenic tolerance