Sand Martin Riparia riparia - Male or female?

Abstract

8,037 examinations were made of brood patches of Sand Martins from 1971 to 1992 in north Nottinghamshire and given one of 12 different descriptions. The 1,997 birds which were examined more than once (5,443 times in total) and identified as 1,061 females and 936 males from the types of patch/es they had carried were then used to test the accuracy with which three distinct types of patch (described in the text) could be used to identify the sex of birds in different periods throughout the breeding season. It was found that females carried at least 98.9% of the Large patches at any time of the breeding season; that males carried at least 96.5% of the Small patches from June to August inclusive but that males carried less than 95% of the Intermediate patches (which formed 29.7% of the patches examined) apart from late in June and in July and males carried only 83.8% of these Intermediate patches in early June and 86.6% in August. It is emphasised that an examination of the cloaca did not form part of this study and was not used to identify the sex of birds in the field. © 1999 British Trust for Ornithology.