Birds of Indian Subcontinent

Escape flight in moulting Tree Sparrows (Passer montanus)

Publication Type:Journal Article
Year of Publication:2001
Authors:J., L
Journal:Functional Ecology
Date Published:2001
ISBN Number:1365-2435
Keywords:life history, moult, Passer, Passer montanus, Passeridae, predation risk, predator evasion
Abstract:Summary* 1 Impaired predator evasion in birds as a cost in different life-history periods has received increasing attention in the last decade. Evasive abilities in birds have been found to be detrimentally affected by migratory fuel load, reproduction and moult. These results suggest that during these periods of their lives birds suffer from increased predation risk due to impaired evasive abilities. * 2 Theoretically, moult should have a detrimental effect on flight, and empirical work on starlings has shown impaired escape ability due to moult. However, a recent theoretical investigation found a surprisingly small effect of moult on flight in birds. * 3 In this study, 31 Tree Sparrows, a sedentary species with a slow moult, were used to investigate the effect of natural and manipulated moult on escape ability. No effect was found due to natural moult, however, when experimentally increasing moult gap size a strong negative effect was found. * 4  With support from empirical and theoretical work, this is the first study to suggest that slow moult may not increase predation risk due to impaired evasive abilities. Compensatory physiological adaptations probably cause this result and may be very important during moult. * 5 Predation risk is probably an important factor in the evolution of moult patterns and moult strategies.
Short Title:Functional Ecology
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith