Hawks win, doves pay for being odd

Apr 13, 2012 By Pete Wilton
Juvenile goshawk hunting by Thermos. Credit: Wikimedia Commons

(Phys.org) -- In a crowd, looking different can be dangerous, at least if you’re a pigeon.

A new study from Oxford University has examined the so-called ‘oddity effect,’ in which predators preferentially attack different-looking individuals within a group - presumably because it enables them to focus on a single target within a confusing, moving mass.

To test whether this hunting strategy actually pays off for the predator in terms of enhanced reproductive success, Christian Rutz of Oxford University’s Department of Zoology studied urban goshawks preying on feral pigeons in the city of Hamburg, Germany.

A report of his research is published in Current Biology.

In feral pigeons, most individuals are grey-blue but many flocks contain a few white birds.

"Goshawks are specialist bird hunters, and in urban environments, their preferred prey is the feral pigeon," says Christian. "When attacked by a raptor, pigeons seek safety in numbers and form a tight flock. Goshawks struggle to single out a suitable victim in such flocks, but by focussing on an odd-coloured individual, they seem to be able to enhance their attack success."

Adult goshawk with pigeon. Credit: Johan Krol

But, Christian explains, like other skills this hunting strategy is something young birds have to learn: "Male goshawks apparently hone their hunting skills over their first few years of life. As they get older, they become not only better pigeon hunters in general, but they also get increasingly selective for odd-coloured individuals."

Importantly, the study found that those hawks that master this selective attack strategy are the best breeders:

"An efficient hunter can provide a lot of food to their offspring," Christian comments. "In goshawks, the most selective pigeon hunters initiate their clutches very early in the season and raise young of excellent body condition."

This finding leads to an intriguing question: why doesn’t this selective hunting drive rare white pigeons to extinction?

"Feral pigeons apparently prefer to mate with partners who are of a different colour to themselves," Christian notes. "Thus, white pigeons may risk paying the ‘ultimate price’ for being conspicuous, and get killed by a hawk, but they are preferred mating partners of their much more common grey-blue counterparts and seem to enjoy reproductive advantages whilst alive."

The work may encourage studies in other species to move beyond simply recording success rates in predators attacking swarming prey, to examine explicitly how different attack strategies may affect a predator’s reproductive performance. 

Explore further: Orchid named after UC Riverside researcher

Related Stories

Pigeons never forget a face

Jul 03, 2011

New research has shown that feral, untrained pigeons can recognise individual people and are not fooled by a change of clothes.

Raptors guard S.African World Cup stadium

May 28, 2010

A South African World Cup stadium has turned to birds of prey to chase out rogue pigeons and rats in an anti-pest strategy that favours raptors above the pitch instead of poisons.

Like monkeys, pigeons can put numbers in order

Dec 22, 2011

(PhysOrg.com) -- Pigeons are on par with primates in their numerical abilities, according to new University of Otago research appearing in the leading international journal Science.

How the 'street pigeon' got its fancy on

Jan 19, 2012

Pigeons display spectacular variations in their feathers, feet, beaks and other physical traits, but a new University of Utah study shows that visible traits don't always coincide with genetics: A bird from ...

Pigeon 'backpacks' track flock voting (w/ Video)

Apr 08, 2010

(PhysOrg.com) -- Pigeon flocks are guided by a flexible system of leadership in which almost every member gets a ‘vote’ but the votes of high-ranking birds carry more weight, a new study has shown.

Recommended for you

Male monkey filmed caring for dying mate (w/ Video)

12 hours ago

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Orchid named after UC Riverside researcher

Apr 17, 2014

One day about eight years ago, Katia Silvera, a postdoctoral scholar at the University of California, Riverside, and her father were on a field trip in a mountainous area in central Panama when they stumbled ...

In sex-reversed cave insects, females have the penises

Apr 17, 2014

Researchers reporting in the Cell Press journal Current Biology on April 17 have discovered little-known cave insects with rather novel sex lives. The Brazilian insects, which represent four distinct but re ...

Fear of the cuckoo mafia

Apr 17, 2014

If a restaurant owner fails to pay the protection money demanded of him, he can expect his premises to be trashed. Warnings like these are seldom required, however, as fear of the consequences is enough to ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Apr 13, 2012
"Feral pigeons apparently prefer to mate with partners who are of a different colour to themselves,"
Perhaps they know that keeping the oddly colored pigeons around helps their own chances of success. Or perhaps that behavior is a product of programming to support genetic diversity within the species, also a good thing.

As far as physorg goes, this article does an above-average job of not making wild extrapolations to humans.

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Plants with dormant seeds give rise to more species

Seeds that sprout as soon as they're planted may be good news for a garden. But wild plants need to be more careful. In the wild, a plant whose seeds sprouted at the first warm spell or rainy day would risk disaster. More ...

Researchers develop new model of cellular movement

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

Male monkey filmed caring for dying mate (w/ Video)

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Treating depression in Parkinson's patients

A group of scientists from the University of Kentucky College of Medicine and the Sanders-Brown Center on Aging has found interesting new information in a study on depression and neuropsychological function in Parkinson's ...