Truce benefits bird neighbours

[klr]

http://www.bbc.co.uk/nature/16249006

Lesser kestrels in Italy have formed a 'truce' with their jackdaw neighbours to save energy, a study has revealed.

Researchers found that birds nesting in a mixed colony patrolled for predators less often than those living in single species sites.

The unlikely co-operation happened despite the birds' conflicting diets as jackdaws can prey on kestrel eggs.

Scientists suggest this could have important implications for the future of the birds of prey.

Up to 20,000 pairs of lesser kestrels are currently thought to exist in Europe and North Africa.

According to BirdLife International, a partnership of conservation organisations, the species suffered rapid declines after the 1950s but they have been recovering in the last three generations.

The sociable raptors roost together in trees and abandoned buildings, preying on small mammals and sometimes other birds.

Mixed roosts

Scientists from the University of Palermo, Italy, noticed the seemingly unusual mixed roosts of kestrels and jackdaws in rural buildings surrounded by cereal crops.

"Jackdaws are opportunist foragers and as such they may be potential predators of kestrel eggs," explained Daniela Campobello whose study was published in the journal Behavioral Ecology.

"The fact that lesser kestrels tolerated them as 'neighbours' triggered us to suspect that it must have been some kind of advantage."

By observing the birds and recording their calling behaviour in response to predator threats, the researchers discovered that both species benefited from the mixed 'neighbourhood'.

Results indicated reduced anti-predator patrols for both species as well as a reduced response by kestrels to threats and less nest attendance by jackdaws, saving them energy.

Ms Campobello theorised that the jackdaws benefited from having 'pugnacious' neighbours: the kestrels deterred other species that might prey on the jackdaws.

This relationship has been described for other species as the 'predator protection phenomenon' but the corresponding role of the kestrels in this instance added a further layer of complexity.

Enemy agreement

"Overall, we would say that there is a reciprocal advantage, where each species' presence allows an optimisation of vigilance and defence efforts," Ms Campobello told BBC Nature.

"These two species, potential enemies, found a truce agreement to look after their own interests."

However, they also found that the jackdaws made more alarm calls when nesting in colonies with kestrels than when they nested alone.

Ms Campobello questioned whether this was the "price paid by jackdaws to lesser kestrels to be allowed to benefit from enhanced colony vigilance?"

The researchers are now investigating the reproductive success of both species to understand how the colony structure could influence the kestrels' future survival.

"Our findings strongly indicate that to improve the conservation status of the lesser kestrels we need not only study this species but also the possible advantages accrued in their interaction with other species," said Ms Campobello.

[devogue]

Shoot ALL the fuckers1111!!!

[klr]

You're in that sort of mood this evening, aren't you? You Kiwis know all about exterminating birds.

[Clinton Huxley]

You're in that sort of mood this evening, aren't you? You Kiwis know all about exterminating birds.

I bet Dev sits on the last Kakapo....

[devogue]

You're in that sort of mood this evening, aren't you? You Kiwis know all about exterminating birds.

I bet Dev sits on the last Kakapo....

What's that? A Maori toilet?

[Clinton Huxley]

You're in that sort of mood this evening, aren't you? You Kiwis know all about exterminating birds.

I bet Dev sits on the last Kakapo....

What's that? A Maori toilet?

Just lets say, if you roast one for your Xmas dinner, you will be in a world of trouble...