Study of incubation, chick rearing and breeding phenology of Red Knots Calidris canutus rogersi in sub-Arctic Far Eastern Russia aided by geolocators
142 – 152
1 September 15
Egor Y. Loktionov, Pavel S. Tomkovich, Ronald R. Porter
Egor Y. Loktionov
N.E. Bauman Moscow State Technical University, 2nd Baumanskaya Str., 5, Moscow, 105005, Russia
This is the first study of the breeding biology of Red Knots of the subspecies Calidris canutus rogersi in the Chukotka region, Far Eastern Russia. Direct behavioral observations and geolocator data of two Red Knots were compared to study the breeding phenology, incubation period and incubation bouts in sub-Arctic Chukotka, a region with twilight around midnight. The incubation period was 23 days after the second or third egg was laid, including about half a day in the nest with the hatched chicks. This corresponds with 21–21.5 days of incubation estimated by the traditional way (interval for the last egg of a clutch from laying to hatching). We suggest that males incubate longer than females. Geolocator data of brooding males after their chicks left the nest differed from those of females that do not attend chicks. Geolocator data might thus indicate the sex of Red Knots. For both males, the lengths of their respective incubation bouts and offduty periods did not significantly differ. Both bout lengths increased in the second half of the incubation period. Brooding time of chicks seems to gradually decrease during the summer, but it was not possible to determine when brooding ceased or when the chicks became independent. Birds started their southward migration 28–28.5 days after families left their nests. This is longer than estimated by direct local field observations and by another geolocator study of Red Knots.