Vultures judge probability of mortality of their prey

Vultures, it seems, weigh up the probability of prey mortality before selecting the prey they will follow. But is this innate sense of statistical probability inherent in their genes or is it just a behaviour taught from one generation to the next?

I suspect it is a learned behavioural pattern which is reinforced by success and which would be given up if it failed. Just habit then and probably not  a genetic knowledge of ststistical probability.

A new paper in PLOS ONE:

Corinne J. Kendall, Munir Z. Virani, J. Grant C. Hopcraft, Keith L. Bildstein and Daniel I. Rubenstein, African Vultures Don’t Follow Migratory Herds: Scavenger Habitat Use Is Not Mediated by Prey Abundance, Published: January 08, 2014, DOI: 10.1371/journal.pone.0083470

vulture

RUPPELL’S GRIFFON VULTURE

Science News: …  if you’re a vulture, following a bunch of fat and happy wildebeest probably means you’re going to go hungry. These carrion-eating birds usually follow the wildebeest herd only during the dry season, when there’s more likely to be dead animals along the migration trail, reports Corinne Kendall of Princeton University and her colleagues in a study published January 8 in PLOS ONE.

Kendall and her colleagues kitted out 39 vultures (15 Ruppell’s vultures, 12 white-backed vultures and 12 lappet-faced vultures) from the Masai Mara National Reserve in Kenya with GPS transmitters and tracked them for months as the birds flew across East Africa. The three bird species each had slightly different patterns of flight — with similar lifestyles, they have to figure out how to not get in each other’s way — but they all showed a preference for visiting the wildebeest herds in Kenya in the dry season, July to October.

That suggests that the vultures take into consideration not only their potential prey’s location but also how likely it is that the prey will die and provide the vultures with a meal. These birds are specialized for eating dead things, after all. Because low rainfall should result in less food for wildebeest and more wildebeest deaths, the best time to find dead wildebeest is during the dry season.

During other times of the year, the vultures took different paths to finding meals. Some went to areas outside the migratory paths, probably trying to find dead animals among the region’s nonmigratory populations. Some headed for other areas of Kenya, such as the Tsavo National Parks. One Ruppell’s vulture took off for three months to a region in Sudan and Ethiopia where a species of antelope, the white-eared kob, follows its own migratory route.

“Despite the fact that migratory wildebeest herds consistently represent the greatest prey abundance in this landscape, vultures selectively associate with them only during the dry season,” the researchers write. “Our study suggests that prey mortality may be a more important driver of vulture habitat use than prey abundance.”

Advertisements

Tags: , , ,


%d bloggers like this: