Biometrics and moult of the Curlew Sandpiper Calidris ferruginea in Australia

Extensive banding of Curlew Sandpipers in south-east and north-west Australia over more than 25 years has enabled considerable biometric and moult data to be collected. There was a marked sexual dimorphism in bill length, a lesser variation in head length and a negligible difference in wing length. Juvenile/first year birds had similar bill and head lengths to adults but slightly shorter wing lengths. There was no difference in these measurements between the two regions. Measurements were also similar to those made on Curlew Sandpipers in other parts of the world, confirming the relative size homogeneity throughout the range. Females were slightly heavier than males and masses in tropical, north-west Australia were lower during the main part of the nonbreeding season than in temperate, south-east Australia. Small mass gains of passage birds in September/ October and large mass gains in February/April before northward migration were apparent in both regions. There were rather more males in the population in south-east Australia in the nonbreeding season and rather more females in north-west Australia. Males migrated before females with consequent changes in the sex ratio at arrival and departure times. Primary moult of adults took approximately four months, being slightly longer in north-west Australia where it also started a month earlier. Second year birds in both regions appeared to moult more slowly, starting before adults but finishing at about the same time. Many first year birds carried out a partial wing moult, mostly of the outer three to six primaries. This started much later than in adults, was less synchronised and exhibited a much slower rate of progression.