About half of all bird nests don't survive due to predators, particularly in fragmented forest areas, but why? University of Illinois researchers monitored both the prey and predator to find an answer.
"Rat snakes accounted for a high percentage of cases of nest predation," said U of I researcher Patrick Weatherhead. "Our hypothesis was that because snakes spend so much more time on the edges of the forest, that's where bird nests should be most vulnerable. And in fact, we never found that." He explained that rat snakes, which in eastern North America are the number one predator to nesting birds, go into the forest to feed, then return to the edges to regulate their body temperature, breed, and shed their skin. "Clearly, a lot of the time they are on the edges they're not actively hunting, because nests on the edges were not at greater risk from the snakes than the nests on the interior of the forest."
Weatherhead said this knowledge of habitat preferences of rat snakes is starting to explain why forest fragmentation usually results in increased nest predation for forest birds.
Fragmented forested areas provide more perimeters, which are beneficial to the snakes. "Snakes really like that interface between the open and closed habitat, whether it's an edge where the forest opens onto a wetland or a rock outcrop or a manmade habitat such as a hay field. So, if your priority is to conserve the birds, you'll want to preserve unfragmented forest habitat," Weatherhead said.
Weatherhead said ornithologists have been interested in fragmentation for a long time. "It's not just that you've lost habitat, but the smaller chunks you're left with aren't as good for a variety of wildlife. The smaller fragmented areas attract birds but they don't do very well there. They've been called ecological traps.
Weatherhead says the message is, if you're going to clear land for agriculture or other development, try to avoid breaking
'/>"/>
| Contact: Debra Levey Larson dlarson@illinois.edu 217-244-2880 University of Illinois College of Agricultural, Consumer and Environmental Sciences Source:Eurekalert |
Related biology news :
1. The song doesnt remain the same in fragmented bird populations
2. Emphasis on conifer forests places multiple species at risk
3. Conservation International and Toyota partner to protect Philippines rain forests
4. Peat and forests save permafrost from melting
5. Spatial patterns in tropical forests can help to understand their high biodiversity
6. Researchers discover forests of endangered tropical kelp
7. Upper Midwest forests are losing diversity, complexity, ISU study finds
8. Study shows housing development on the rise near national forests
9. Why do so many species live in tropical forests and coral reefs?
10. Wildfire drives carbon levels in northern forests
11. Univ. of Arizona receives $2.5 million to study Amazon forests and climate change
 |
| Copyright © 2003-2012 Bio-Medicine. All rights reserved. ABOUT | CONTACT US | DISCLAIMER | PRIVACY POLICY | TERMS AND CONDITIONS |  |