Southern Chickadees Moving North, Will Invade Canada Under Global Warming

Biologists know that climate change is causing southern species' ranges to move northward in the Northern Hemisphere. But little research has been done on the indirect ways climate change is influencing biodiversity, such as the poleward migration's impact on the ranges of species already residing in the north. What will the distribution of species look like across North America in the year 2050?

New research on northern (black-capped) and southern (Carolina) species of chickadees offers some answers. Amber Rice, assistant professor of biological science at Lehigh and her co-author Michael A. McQuillan, a graduate student studying integrative and evolutionary biology, looked at the predicted effects of climate change on both species of chickadee with an eye toward examining how rising temperatures are influencing their location. They also looked at how other matters are factoring in to the species' range limits - such as interactions between the species, like hybridization, which is when individuals from different species mate and produce offspring.

Findings from the study, published in a paper called "Differential effects of climate and species interactions on range limits at a hybrid zone: potential direct and indirect impacts of climate change" in the November 2015 edition of Ecology and Evolution, have implications beyond chickadees.

"We found that climate change can both directly and indirectly affect species distributions and hybrid zone location," says McQuillan. "Additionally, our results lend support to the hypothesis that physical factors regulate species' poleward range limits, while biological factors shape range limits near the equator."

To begin the study, Rice and McQuillan collected information about where each of the chickadee species occurs and recorded climate information from each location where the birds have been observed. Then they projected the data onto a map and identified areas where the climate is most suitable for each species. When they compared the suitable areas to the areas where the birds are actually located, they found that the northern species was often absent from large areas with suitable climate.

"We speculated that the lack of the northern chickadee species in areas you would expect them to be could be attributed to competition or hybridization," said Professor Rice. "We discovered that the two types of chickadees are being affected differently: the southern species--the Carolina chickadee--is being pushed north due to climate change and the northern species--the black-capped chickadees--are being displaced by the southern species of chickadees as a result."

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Do Crows Hold Funerals?

Many who have heard the melancholy cry of the mourning dove might wonder: Do birds grieve for their loved ones?

For this Saturday’s Weird Animal Question of the Week Emilie Bouef commented via Facebook: "I heard that ravens do some kind of funeral when one of them dies. I’d love to know more about this."

Calling to each other, gathering around, and paying special attention to a fallen comrade is common among the highly intelligent corvids, a group of birds that includes crows, jays, magpies, and ravens, says Kaeli Swift, a Ph.D student in biology at the University of Washington.

But it doesn't necessarily mean the birds are mourning for their lost buddy. Rather, they're likely trying to find out if there's a threat where the death occurred, so they can avoid it in the future.

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New Zealand Holocene Quaternary Giant Moas may not Have Been Robust Birds

Giant moa bird (Dinornis robustus, literally meaning 'robust strange bird') may not have actually had robust bones, according to new research conducted by The University of Manchester. The leg bones of one of the tallest birds that ever existed were actually rather like those of its modern (but distant) relatives, such as ostrich, emu and rhea, the studypublished in PLOS One today (18 December) shows.

The study, led by biomechanics researcher Charlotte Brassey, in collaboration with palaeobiologist Professor Richard Holdaway at the University of Canterbury in New Zealand, has found that the largest of the moa species had leg bones similar to those of modern flightless birds that can run fast, whereas a much smaller species of moa – from a different family - had an extremely robust skeleton.

Ms Brassey said:"Our research suggests that this group of birds came up with several different solutions to deal with the problem of supporting the large body necessary to process a diet of coarse vegetation.

"We know that these species of moa were living together in the same locations, at the same time. So we don't think the differences we're seeing in leg robustness are adaptations to a particular habitat type.

"Instead it seems they were perhaps engaging in different behaviours, although both could deal with extremely rough terrain."

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