No early birds getting the worms: York U study finds songbirds risk missing peak food supply

Jun 03, 2013
This is an adult male purple martin outfitted with a geolocator. Credit: Nanette Mickle

A mismatch between the departure schedules of songbirds and higher spring temperatures at their breeding sites is putting them at risk, according to a new study out of York University.

The study, "A Trans-Hemispheric Migratory Songbird Does Not Advance Schedules or Increase Migration Rate in Response to Record-Setting Temperatures at Breeding Sites", published in the journal PLOS ONE, tracked the spring migration of purple martins over five years from the to two breeding sites in eastern North America. Researchers outfitted the birds with tiny geolocator "backpacks" to record data on their movements and found that the birds' departure times between years were surprisingly consistent, despite variation in temperature at their final destination.

"We found that purple martins migrating between the Amazon Basin and North America did not adjust their migration timing even during the hottest spring on record in 2012," says study author Kevin Fraser, a in York's Department of Biology, Faculty of Science. "This means that they arrived 'late' for the advanced spring, and likely missed out on peak food they need to be productive breeders."

Aerial insectivores, like purple martins and other swallows, are experiencing strong , particularly species migrating longer distances and populations breeding further north. Scientists have shown in a European species that declines may be due to an inability to advance arrival schedules to match a warming climate. This study provides the first direct evidence of a discrepancy between higher spring temperatures at breeding sites and departure schedules of individual songbirds.

"Our results suggest that long-distance migrants may receive limited or conflicting environmental cues about conditions at the breeding grounds while still at overwintering sites or along ," says Fraser. "Once en route, the birds received no temperature cues of the warm spring until they reached the US Gulf coast, at which point it was likely too late to get to breeding sites earlier." Fraser says such mistiming is an active area of new research, and with climate change may be an important contributing factor to migratory songbird declines.

"Some migratory songbirds may not have the flexibility they need to respond quickly to earlier springs and more variable weather with climate change, which could contribute to the strong population declines we see in many species. Identifying which species or populations may be at greatest risk will be very important for guiding effective conservation action."

He says the study suggests that migration timing and rate in purple martin is not highly sensitive to short-term variation in temperature and rainfall, and that multiple years of increasing spring temperatures may be required to shift the birds to an earlier breeding arrival time through natural selection for earlier departure from tropical overwintering sites.

Explore further: GMO mosquito plan sparks outcry in Florida

add to favorites email to friend print save as pdf

Related Stories

Drought in the Horn of Africa delays migrating birds

Dec 06, 2012

The catastrophic drought last year in the Horn of Africa affected millions of people but also caused the extremely late arrival into northern Europe of several migratory songbird species, a study from University ...

Songbirds fly 3 times faster than expected (Video)

Feb 12, 2009

A York University researcher has tracked the migration of songbirds by outfitting them with tiny geolocator backpacks - a world first - revealing that scientists have underestimated their flight performance ...

Recommended for you

GMO mosquito plan sparks outcry in Florida

1 hour ago

A British company's plan to unleash hordes of genetically modified mosquitoes in Florida to reduce the threat of dengue fever and other diseases has sparked an outcry from fearful residents.

Population genomics unveil seahorse domain

20 hours ago

In a finding vital to effective species management, a team including City College of New York biologists has determined that the lined seahorse (Hippocampus erectus) is more a permanent resident of the we ...

Researchers develop new potato cultivar

23 hours ago

Dakota Ruby is the name of a new potato cultivar developed by the NDSU potato breeding project and released by the North Dakota Agricultural Experiment Station. Dakota Ruby has bright red skin, stores well and is intended ...

Researchers develop new soybean variety

23 hours ago

The North Dakota Agricultural Experiment Station has developed and released ND Henson, a conventional soybean variety, according to Rich Horsley, chair of the NDSU Department of Plant Sciences.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.