The nesting ecology and postembryonic development of the Columba rupestris in Tuva and Buryatia

A material on the nesting ecology of Columba rupestris was collected in southern Siberia on the territory of Tuva and Buryatia. The Columba rupestris lives sedentary in various types of localities and a small proportion – in the natural rocks of open spaces. The number of this species has now decreased by 3–5 times compared to the 70–90-es of the 20^th century. It is due to the deterioration of the food supply as a result of the elimination and reduction of arable land near settlements, the reduction of livestock in private households, changes in the architecture and construction material of buildings, first of all, the replacement of slate roofs with metal profiles. The most preferred localities are medium and small rural settlements located in forest-steppe and steppe landscapes. The deterioration of habitat conditions affected the structure of nesting settlements, and colonies became small (no more than 30–50 birds compared to 100–200 individuals at the end of the 20^th century). Breeding periods in localities are stretched from late February to mid-October, but the majority of populations breed from the 20^th of March to the end of July. Birds manage to hatch their сhicks 2–4 times, 2,4 times on average. There are 2 eggs in a clutch, incubation lasts 17 days, and the сhicks leave the nest at 26 days of age. The paper presents features of growth and development of chicks. Nesting efficiency (ratio of the number of chicks that have reached sexual maturity to the total number of eggs laid) equals to 27%. It is noted that currently interspecific hybridization of Columba rupestris and Columba livia, which was observed relatively often in the second half of the 20^th century, has almost stopped due to a decrease in the number of both species, which led to greater spatial differentiation.