Journal article

Publication year: 2005

Pages: 171-178

Journal: Ardea -Wageningen-

Volume number: 93

Issue number: 2

ISSN: 0373-2266

URL: http://www.ardea.nou.nu/contents.php?key=choice

Publisher: Nederlandse Ornithologische Unie

Abstract: 
Parental investment in a breeding attempt involves trade-offs between current reproduction and adult survival and thus, future reproduction. Furthermore, the investment must be distributed between male and female offspring. In the present analysis, we study risk-taking in incubating female Upland Geese Chloephaga picta in relation to the reproductive value of the clutch. We found that the flushing distance of incubating females during a simulated predator approach was decreased during the later stages of incubation, and in females with larger clutches and larger total clutch volumes. The results were in line with parental investment theory; indicating that risk-taking is increased with the value of a clutch. In addition, we studied the sex ratio of juveniles. We found that more families had male-biased than female-biased broods at 2 months of age, and that the total number of male juveniles exceeded that of females by 50%. The density of breeding pairs of Upland Geese at New Island South, Falkland Islands, is very high. There is evidence that territorial fights between males contribute substantially to male mortality and this might be a driving factor selecting for a male-biased sex ratio in offspring. Alternatively, fewer females than males may be produced to avoid local resource competition, as females are the more philopatric sex.

Harvard Citation style: Quillfeldt, P., Strange, I. and Masello, J. (2005) Escape decisions of incubating females and sex ratio of juveniles in the Upland Goose Chloephaga picta, Ardea -Wageningen-, 93(2), pp. 171-178. http://www.ardea.nou.nu/contents.php?key=choice

APA Citation style: Quillfeldt, P., Strange, I., & Masello, J. (2005). Escape decisions of incubating females and sex ratio of juveniles in the Upland Goose Chloephaga picta. Ardea -Wageningen-. 93(2), 171-178. http://www.ardea.nou.nu/contents.php?key=choice