Why fly? The possible benefits for lower mortality
Article first published online: 14 JAN 2008
Biological Journal of the Linnean Society
Volume 40, Issue 1, pages 53–65, May 1990
How to Cite
POMEROY, D. (1990), Why fly? The possible benefits for lower mortality. Biological Journal of the Linnean Society, 40: 53–65. doi: 10.1111/j.1095-8312.1990.tb00534.x
- Issue published online: 14 JAN 2008
- Article first published online: 14 JAN 2008
- Received 28 October 1989, accepted for publication 13 June 1989
- mortality rates;
In adult endotherms—birds and mammals—mortality rates are lower in flying than non-flying species. Rates vary with size, but allowing for this they are higher in penguins than flying birds, and in rodents than bats. These observations are most simply explained in terms of predation since flight, allowing movement in three dimensions, increases the chances of escape.
There are various problems in obtaining and comparing data on rates of mortality and this partly explains a wide scattering of points. Nevertheless the main results are statistically significant, mostly at P<0.001. Amongst birds, there are several other significant differences. Mortality rates are lower at lower latitudes, and in aquatic compared to terrestrial species, with cliff-nesters having lower rates than other aquatic birds and co-operative breeders than other terrestrial ones. No latitudinal effect was detected in mammals. The exceptionally low rates of mortality in bats and swifts are attributed to their being particularly hard to catch.