Nesting behaviour of Capercaillie (Tetrao urogallus) females kept in aviaries

Abstract

For many bird species in captivity the best practice for incubation procedures have not been yet developed. This is hampered by a lack of cooperation between bird breeders or by a reluctance to experiment on valuable eggs. The last two problems may be solved by observation of natural incubation, which technology has made a lot easier. Many studies document incubation behavior: daily time spend in the nest, preferred hours of making abscences, egg turning rate and incubation temperature. Such data is scientifically interesting but also allows for better protection of endangered species through development of captive breeding programmes. The Capercaillie (Tetrao urogallus) is a threatened species over much of its European range and various conservation actions are being taken to save populations from global or local extinction. Our study took place in Capercaillie Breeding Centre in Wisla Forestry District and describes nesting and incubation behaviour of Capercaillie females kept in captivity. Our aim was to better document the nesting behaviour by recording egg turning rate, and the time and length of incubation recesses. Time of and day of incubation had no significant influence on recess length, but the number of recesses was related with time of day with two peaks at 06:00h and 18:00h . Egg turning activity was the greates during the first and last two days of incubation but generally consistent throughout the rest of incubation. Captive hens spent less time outside of the nest than wild ones, their absences were shorter, rarer and took place mostly in the evening. However, differences in the preferred absence hours were not as clearly markes as in the case of wild birds. We hope that this information will help improve management practises to maximise the reproductive output of captive Capercaillie.