Age, Sex and Prior Site Experience Have Independent Effects On the Foraging Success of Wintering Snow Buntings

• Published in: Behaviour
• Main Authors: Smith, Richard D., Metcalfe, Neil B.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Brill 1994
• Subjects: Behavioral Neuroscience; Animal Science and Zoology; Cairn; Plectrophenax nivalis
• Online Access: http://dx.doi.org/10.1163/156853994x00370; https://brill.com/view/journals/beh/129/1-2/article-p99_6.xml; https://brill.com/downloadpdf/journals/beh/129/1-2/article-p99_6.xml

Abstract Intraspecific variation in foraging success amongst birds is often associated with differences between individuals in competitive ability or experience. However, it is usually difficult to separate the importance of experience per se from that of age. Here we examined the feeding rates of wintering snow buntings (Plectrophenax nivalis) at Cairn Gorm, North-east Scotland in both competitive and non-competitive situations. Although flock-size/density and stage of the feeding bout accounted for most of the explainable variation in peck-rates, there remained significant and additive residual effects of both age and prior experience of the site (older/more experienced birds achieving higher feeding rates) and these effects were very similar for birds feeding alone or in flocks. Sex differences in feeding rates were only apparent in large flocks, where males (the dominant sex) had faster peck-rates than females. Birds without previous experience (whether age or site-related) showed increases in relative feeding rate during the course of the winter, whereas experienced birds did not. This suggests that the differences between experienced and inexperienced birds were due to learning rather than the disproportionate loss of poor foragers.