Field identification of White-headed Vultures using plumage patterns
Identifying individuals during the study and management of animal populations is often difficult and has lead to the development of various methods of marking to facilitate re-sightings.
Identifying individuals during the study and management of animal populations is often difficult and has lead to the development of various methods of marking to facilitate re-sightings. However in some cases study animals cannot be marked for reasons such as cost, safety or logistics. Variation in natural markings can sometimes be sufficient to identify individual animals and this has been used successfully for a variety of taxa, particularly marine and terrestrial mammals, but more rarely for birds. Using an information theoretic approach, this study outlines a novel method of identifying individual White-headed Vultures Trigonoceps occipitalis using patterns in the median wing covert feathers. The individually distinctive median covert pattern is highlighted for the first time, and the information content of this pattern is shown to be high (median information content 23.54 bits, range 17.22 – 40.06 bits). The probability of pattern recurrence in a population of approximately 10 000 birds is very low (2.04 x 10-3) and is thus a reliable means of identifying individual birds. The pattern does not change noticeably between years and is possibly maintained for many years. This non-invasive identification technique is reliable and is suitable for cataloguing local and regional populations of adult White-headed Vultures, thus facilitating mark–recapture studies or other studies that require identification of individuals.