Daily activity and nest attendance in a breeding pair of Parrot Crossbills Loxia pytyopsittacus in southern Norway

Abstract

Crossbills Loxia spp. breed during late winter and early spring and feed their nestlings almost exclusively with seeds from conifer cones. In the present paper, we studied a breeding pair of Parrot Crossbills Loxia pytyopsittacus from dawn to dusk in Southern Norway using a time-lapse camera. The study was conducted in the second half of the nestling period, when the nestlings were from 10 to 21 days old and capable of keeping warm without assistance from the female. Almost all recorded parental nest visits involved feeding the nestlings. The average number of feeding visits was about 10 visits per day by each parent and these visits were distributed evenly throughout the day, starting about 30 min after sunrise and ending 60 min before sunset. Parents fed the young regularly at about 1-hour intervals. The female feeding duration was constant throughout the period, whereas the male feeding duration was longer initially, but decreased compared with the female later in the nestling period. In most feeding visits, the male and female arrived at the nest at the same time or shortly after to each other. The probability of parents removing nestlings’ faecal sacs was very high during the early period, but decreased as the nestlings became older. Overall, our use of modern camera monitoring technology enabled a more comprehensive description of a pair of Parrot Crossbill’s daily activity patterns and nest attendance behaviour than previous studies conducted by observations from a hide.