Using wing length for sexing Eurasian Skylark <i>Alauda arvensis</i>: examples from a British population

The Skylark Alauda arvensis is a common, yet rarely ringed species. Outside the breeding season, determining sex of individual birds problematic. While previous studies have provided sexually dimorphic ranges wing length, those based on accurate DNA sexing focus Continental populations, which are subject to seasonal influxes migrants. In Britain, largely sedentary species, and guidelines in-the-hand might be inappropriate. Here we present comparative analysis morphometrics for 137 Skylarks, assess accuracy using length trapped birds. We suggest that with measurements 107–109 mm classified as ‘undetermined’ sex, below this range being female above male.