It looks like a blue Christmas for Manitoba's warbler population.

A study out of the University of Manitoba, led by Ph.D. student Laurel Moulton, has found evidence that golden-winged and blue-winged warblers are interbreeding in Manitoba -- something that happens elsewhere in the world but is less common here.

Moulton's genetic research found golden-winged warblers with blue-winged DNA, as well as visibly hybridized birds.

Dr. Nicola Koper, the professor who supervised the study, says in almost every other population where the two species interbreed, within 50 years the blue-winged warblers have completely taken over.

"The two species were separated from each other by forest historically, but with habitat loss and habitat fragmentation through human development, that fragmentation brought the two species together and they started to interbreed," says Koper.

She says seeing evidence of that interbreeding happening here is a concern. She says the majority of Manitoba's warblers are golden-winged, and we're the only place in the world where that occurs, making their conservation internationally relevant. Koper also says we need to consider what kind of world we want to live in.

"A golden-winged warbler is an extremely pretty bird: yellow, black, white, and grey; it's really pretty, really flashy. And it's something that we have in Manitoba that's sort of right outside our doors, and I think we need to think about whether we want to protect those kinds of interesting and beautiful parts of our ecosystems for our future generations."

She says golden-winged warblers also eat leaf-roller caterpillars, an agricultural pest.

Koper says interbreeding and habitat loss both contribute to a decline in golden-winged warbler numbers. To conserve them, we can provide them with the best breeding habitat possible:

"So they need early successional forests, which are forests like poplar -- the trees that grow up really quickly. So that's actually where they breed. But when they have babies, they bring their fledglings into older forests, more mature forests, and so we need both types of forests basically to be conserved on our landscape."

Koper says, ultimately, individual birds will mate with whomever they choose, and when blues and golds are in the same area they do sometimes start breeding together. She says we want to manage our systems in a way that allows evolution to move forward unhindered, but we do know if humans hadn't interfered with habitat, both golden-winged and blue-winged warblers would be able to co-exist in different locations. She says we can't do much about hybridization, but we can give the birds a good habitat. 

Golden-winged warblers do well in wetter areas, blues do well in drier areas.

Koper says she'll be speaking with Manitoba Sustainable Development next week.

The study is published in this month's issue of Conservation Genetics.