Snakes devour more mosquito-eating birds as climate change heats forests

July 11, 2013

Many birds feed on mosquitoes that spread the West Nile virus, a disease that killed 286 people in the United States in 2012 according to the Centers for Disease Control. Birds also eat insects that can be agricultural pests. However, rising temperatures threaten wild birds, including the Missouri-native Acadian flycatcher, by making snakes more active, according to University of Missouri biologist John Faaborg. He noted that farmers, public health officials and wildlife managers should be aware of complex indirect effects of climate change in addition to the more obvious influences of higher temperatures and irregular weather patterns.

"A warmer climate may be causing snakes to become more active and seek more baby birds for food," said Faaborg, professor of biological sciences in MU's College of Arts and Science. "Although our study used 20 years of data from Missouri, similar threats to bird populations may occur around the world. Increased snake predation on birds is an example of an indirect consequence that forecasts of the often do not take into account."

In the heart of Missouri's Ozark forest, cooler temperatures usually make snakes less active than in the edge of the forest or in smaller pockets of woodland. However, during abnormally hot years, even the interior of the forest increases in temperature. Since snakes are cold-blooded, warmer temperatures make the reptiles more active and increase their need for food. Previous studies using video cameras found that snakes are major predators of young birds.

Over the past twenty years, fewer young Acadian flycatchers (Empidonax virescens) survived during hotter years, according to research by Faaborg and his colleagues published in the journal Global Change Biology. Survival of young indigo buntings (Passerina cyanea) also decreased during warmer years. Faaborg suggested that a likely reason for decreased baby bird survival in hot years was an increase in snake activity. Faaborg, his colleagues and his former students, collected the data used in the study during two decades of fieldwork.

"Low survival in the Ozark nests harms bird numbers in other areas," Faaborg said. "Birds hatched in the Ozark forest spread out to colonize the rest of the state and surrounding region. Small fragments of forests in the rest of the state do not support successful bird reproduction, so in the entire state depend on the Ozarks."

Explore further: Fragmented forests result in more snakes, fewer birds

Related Stories

Climate adaptation difficult for Europe's birds

January 17, 2012

Åke Lindström is Professor of Animal Ecology at Lund University, Sweden. Together with other European researchers he has looked at 20 years' worth of data on birds, butterflies and summer temperatures. During this ...

Global warming beneficial to ratsnakes

January 8, 2013

Speculation about how animals will respond to climate change due to global warming led University of Illinois researcher Patrick Weatherhead and his students to conduct a study of ratsnakes at three different latitudes—Ontario, ...

Blue tits provide insight into climate change

April 15, 2013

( —Researchers believe that the size of birds' nests created in response to changing weather patterns may be partly to blame for reproductive failures over the last two years.

Recommended for you

Trade in invasive plants is blossoming

October 3, 2015

Every day, hundreds of different plant species—many of them listed as invasive—are traded online worldwide on auction platforms. This exacerbates the problem of uncontrollable biological invasions.

Ancestral background can be determined by fingerprints

September 28, 2015

A proof-of-concept study finds that it is possible to identify an individual's ancestral background based on his or her fingerprint characteristics – a discovery with significant applications for law enforcement and anthropological ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

1 / 5 (4) Jul 12, 2013
If bullshit were gold these AGW Alarmists would be wealthy.

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.