Primary spacing as a field identification criterion for Iberian Chiffchaff

By Marcel Gil-Velasco Abstract Differences in the primary spacing between Iberian Chiffchaff Phylloscopus ibericus and Common Chiffchaff P. collybita are described, based on measurements from good-quality photographs of birds on the breeding grounds. In some situations, this may be a useful supplementary feature for field identification.

An example of how primary spacing in an Iberian Chiffchaff Ph