Responses of Foraging Sanderlings To Human Approaches

• Published in: Behaviour
• Main Authors: Roberts, Gilbert, Evans, Peter R.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Brill 1993
• Subjects: Calidris alba
• Online Access: http://dx.doi.org/10.1163/156853993x00326; https://brill.com/view/journals/beh/126/1-2/article-p29_3.xml; https://brill.com/downloadpdf/journals/beh/126/1-2/article-p29_3.xml

Abstract Sanderlings Calidris alba were put to flight by walking towards them as they foraged at the water's edge on a sandy beach. Studies of the responses of birds to disturbances have concentrated on the relationship between group size and the distance from the cause of the disturbance at which members of the group take flight (the flight reaction distance). The study of responses to disturbance is extended to consider the frequencies with which birds took flight; their flight directions (whether towards the approacher and then in behind or whether ahead of the approacher); and the distances to which they flew. The nearest birds to the approacher tolerated approaches to well within the range at which the approacher should have been visible. When the nearest birds flew, the likelihood of other birds flying decreased as the distance by which they were further away from the approacher than the nearest birds increased. Birds further away were more likely to fly when more birds flew from nearer to the approacher. The nearest birds tended to fly in behind the approacher while those further away from the approacher flew further ahead. The findings suggested that the birds were acting so as to maximise their foraging time by minimising both the number of flights they made and the distance of each flight, subject to not tolerating close approaches.