Growth of nestling Sand Martins

Abstract

Several aspects of sand martin development were investigated at Dunblane (Perthshire) in 1977 and 1978. Measurements were made of weight, wing length, length of 9th primary, tail, tarsus, bill and gape width. The lipid content of some nestlings was also measured. The sand martin nestling reaches a peak weight of 16.2 g on the 12 day but then loses weight, fledging at about 13 g. The nestling period is 22.3 days. The lipid index (ratio of fat content to fat free dry weight) is 0.4-0.8 for nestlings at or over peak weight. Comparisons are drawn between the sand martin and the swallow [Hirundo rustica], house martin [Delichon urbica] and bank swallow Regressions of wing length and 9th primary length on age were calculated and used for ageing nestlings of unknown hatching date.