When you're a bird of prey, height is to your advantage. Perching in a high tree or on top of a building allows a raptor to scan the surrounding countryside, looking for mice or other creatures that would make a good meal. But sometimes the perch can put them at risk.
That's the case at many landfills, where raptors land on top of large smokestacks designed to release methane gas generated by decaying organic matter deep in the landfill. The smokestacks can contain burners, which periodically ignite the methane to get rid of it. If a bird is sitting on top of one of these burners when it ignites, it can be killed or fatally wounded.
Statistics on the number of birds are affected by these burners do not exist — some groups estimate that for every one injured or dead bird found, 10 more have been affected — but burned raptors have been found in California, New York, Michigan, Texas and 10 other states, as well as two Canadian provinces, according to a January 2013 study (pdf) funded by an energy company and several birding organizations.
The problem has probably been going on for years, but the U.S. Fish and Wildlife Service, which protects bird of prey under the Migratory Birds Treaty Act, only found out about the problem in 2009. "This issue was brought to our attention recently and in many cases, when landfill operators were notified that there were injured birds because of the flare, the landowners were not aware of the problem," a spokesperson told the Associated Press that year.
Ever since then, the waste industry and birding organizations have been working together to minimize the deaths. A 2010 presentation (pdf) by the Huntington-Oyster Bay Audubon Society and the Solid Waste Association of North America discussed the situation and how the burners affect birds. Injuries caused by the burners include melted beaks, talons and feathers, which can either kill the birds immediately or cause them to "slowly starve to death." Since landfills are usually in low-traffic, highly vegetated areas and are often fenced off and inaccessible – or even closed after decades of use – many of these injuries or deaths are never observed.
The 2010 presentation outlined several options that landfills can put in place to help minimize the risk. Spikes, excluders and other anti-perching devices can keep birds away from the flames. Adding second perching stations higher than and away from the flames gives birds a safer option and a more advantageous perching site. The best solution, though, is reclaiming and recycling the methane, which eliminates the need for flaring in the first place.
The 2013 study goes into more detail about various anti-perching devices, using the experience of the power industry — which aims to keep birds off of power lines — as its model. It also includes diagrams showing how poles around a landfill should be situated to minimize the possibility of birds circling directly over an open burner, as the birds can also be injured during flight. Knowing how local birds behave is key, according to the report, which concludes with the message that "Mitigating methane burns will be most successful if collaborate approaches are used utilizing expertise from industry engineers along with wildlife biologists familiar with raptor behavior."
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