Warmer springs could be leading to population declines in birds

Tuesday, June 4, 2013, 9:55 AM -

New study finds that many birds are unable to adjust their migratory schedule to match warmer temperatures arriving earlier in the year.

Warmer weather could be affecting the efficiency of the Purple Martin's migratory schedule. (Image: Kevin Fraser)

It looks like some birds are no longer early enough to get the worms. 

A new study coming from York University has found that songbirds like the purple martin are not adjusting their migration timing to reflect the warmer spring temperatures. 

As a result the birds are arriving "late" for an advanced spring which in turn leads to most purple martins missing out on the "peak food periods" they need for a productive breeding season. 

The birds were tracked using a geolocator "backpack" (Image: Nanette Mickle)

The study was conducted by Kevin Fraser, and tracked the spring migration patterns of purple martins over five years. Researchers outfitted the birds with tiny "backpacks" that recorded data on their movement. 

Purple martins and other swallows have been seeing large population declines in the last several years. An earlier study focusing on European species showed that declines could be linked to the birds' inability to synchronize their migratory patterns to reflect the changes in temperature. 

The recent York study is the first to provide direct evidence of a discrepancy between the higher temperatures of the purple martins' breeding sites and their migratory departure schedule.