Sea birds as fickle as humans

Sydney, Nov 24 ( Australasian gannets are as fickle as humans when it comes to fidelity but risk breeding failure with a new partner, says a new study.

“It’s always been assumed that these birds are monogamous, and they’ve been held up as an example of fidelity for humans,” says Steffi Ismar of the University of Auckland (U-A), who led the research.

“In fact, our research has shown that the divorce rate from one breeding season to the next is around 40 percent,” says Ismar.

The novelty of this finding may say as much about how humans view the world as about the large sea birds themselves.

The study also showed that single birds which divorced and found a new mate were less likely to successfully raise a chick in their first breeding season, compared with those who stuck with the previous year’s partner.

This may be due to the common phenomenon of breeding failure in newly-formed couples, followed by success at subsequent attempts, amongst species that require teamwork to raise their young.

“Like many animals, Australasian gannets cooperate to raise their chicks, taking turns to incubate and feed their young, and look after themselves,” says Ismar.

“Birds who have secured a good territory can’t wait for ever for their old mate to arrive — eventually they just have to get on with it,” Ismar says.

The research team studied banded Australasian gannets at Cape Kidnappers during consecutive breeding seasons in 2007-08 and 2008-09.

These results were published online in Naturwissenschaften.