Ecology and reproductive biology of the European Roller Coracias garrulus L., 1758 in Stavropol Region

Abstract

The results of study of the ecology and biology of the European Roller in the Stavropol Region during the period of agricultural transformation of the environment in 1984–2019 are presented. Favorable conditions for this bird species are found in steppe areas used for grazing animals and on non-irrigated arable land. Rollers nest mainly in holes in natural cliffs (46.9% of the total number of nests) and cliffs of anthropogenic origin (37.4%), as well as in tree hollows (15.7%). The nesting period of the population (the time of pairing, nest building, egg laying, development, and growth of nestlings, and feeding of nestlings) has characteristics that are associated with traditional agriculture. At the same time, the largest clutch size known for European populations, of seven eggs was found, and the eggs were somewhat smaller than in most of the range. The average clutch size (4.43 ± 0.17 eggs) and brood size (3.43 ± 0.13 chicks) correspond to the range optimum. The breeding success is 77.5%. A cautious assumption is made that the increase in clutch size and decrease in egg size may be an adaptive response of the species to changes in habitat in the last 30–50 years.

Keywords

• adaptation
• behavior
• problems of biodiversity conservation
• rare and endangered species
• rate of environmental change