Sex roles in the monogamous Purple Sandpiper Calidris maritima in Svalbard

Abstract

The Purple Sandpiper Calidris maritima, an Arctic shorebird, displays unusual sex roles during breeding. In a 5‐year study in Svalbard, in the Norwegian high Arctic, data were collected on the roles of the sexes in this species. Purple Sandpipers were similar to most shorebirds in that males actively courted females, established territories and vigorously defended their territories from intruders. Both sexes shared incubation duties approximately equally over the entire 21‐day incubation period. Males incubated very little initially, but increased their effort significantly during the first 11 days of incubation to over 50% of the time from days 11–21. However, Purple Sandpipers contrasted with most other shorebird species in that females discontinued their breeding efforts at hatching. In nearly all cases, broods were attended solely by the male until the chicks reached fledging age (or even longer). Nonetheless, the pair bond must be described as monogamous because neither males nor females were found to re‐mate or lay a second clutch during a season. This pattern of parental care, which is found only in very few other shorebird species, is discussed in an evolutionary context.