BREEDING ECOLOGY OF TURNSTONES ARENARIA INTERPRES AT HAZEN CAMP, ELLESMERE ISLAND, N.W.T.

• Published in: Ibis
• Main Author: Nettleship, David N.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1973
• Subjects: Ellesmere Island; Hazen Camp; The Beaches; Arenaria interpres; Tundra
• Online Access: http://dx.doi.org/10.1111/j.1474-919x.1973.tb02637.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1474-919X.1973.tb02637.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1474-919X.1973.tb02637.x

Summary. Turnstones arrive on Ellesmere Island in late May or early June. Pair‐formation takes place during migration, or after arrival in courtship groups along the beaches, or on the nest territory, depending on weather conditions. Pair‐formation was not observed at Hazen Camp in 1966 as most birds were already paired when observations began on 3 June. The preferred nesting habitat was Dryas ‐hummocked tundra closely associated with a marsh, stream, or pond. A census area of 240 ha supported 13 breeding pairs, possibly 14; the total number of pairs breeding in the Hazen Camp study area was estimated to be 70 (3.04 pairs/km 2 ). Egg‐laying began on 10 June, with 46% of the first eggs laid 13–15 June. 62% of the sets were completed between 19 and 21 June. Both sexes incubated, the female regularly and the male sporadically. Hatching was also well synchronised; most clutches hatched between 7 and 14 July. Nest success was high (79%). After hatching territories dissolved and family groups moved freely over the tundra, concentrating at ponds where food was readily available for the young. Both adults attended the young during the pre‐fledging period, but the females apparently departed long before the young fledged. Males left once the young could fly and the adult fall migration was complete by early August with the exception of late breeders. Most of the young departed in the second half of August. Fall migration is complete by late August or early September. The breeding season appears to be timed so that the young are raised when food is most abundant. Food supply (dipterous insects, especially adult chironomids) was highest from 8 to 12 July at the peak of the hatching period. While food supply for the young declined during the growing period, the early departure of half the adult population, and family movements over the tundra, appeared to reduce the food demand correspondingly. Food appeared to influence the distribution of breeding pairs markedly, restricting them to the vicinity of marshes, streams, and ...