Birds face numerous predators

2013-05-11T00:00:00Z 2013-05-11T08:38:03Z Birds face numerous predatorsBy Rich Landers The Spokesman-Review The Billings Gazette
May 11, 2013 12:00 am  • 

It's unfortunate that birds don't scream when they die; the din might catch our attention.

The killing fields are all around us, from the glass windows in the city to the wind farms on the mountain ridges and from chemically treated prairies to our own backyards.

Habitat fragmentation may be the top culprit, killing birds indirectly by eliminating or cutting them off from the space and natural landscape they need for feeding, nesting, surviving migrations, toughing out the extremes of weather and seasons and evading predators.

Hanging a bird feeder doesn't make up the difference, but programs, both local and national, that preserve open space are a huge step in the right direction.

About a third of U.S. bird species and subspecies need some form of conservation attention, according to research by the American Bird Conservancy. Other recent studies on bird deaths indicate some of the reasons why.

Millions of birds are killed each year by flying into windows. At home we can minimize the carnage with various techniques, including decals, wind ornaments and vertical strips of tape.

The rotating blades in wind farms take a high toll, especially on raptors. Research is helping wind farm operators reduce the impact. Turbine design and locations of wind farms must be scrutinized. Even small changes in the rotation of the blades can make a big difference.

U.S. Geological Service Breeding Bird Surveys have helped researchers document declines of grassland birds which are more likely in states with high use of toxic insecticides lethal to birds. Species with the greatest declines include the Eastern meadowlark (declining in 33 states), grasshopper sparrow (25 states), horned lark (25 states), ring-necked pheasant (19 states) and vesper sparrow (18 states).

The Associated Press reported last week that millions of birds are killed each year by the hollow plastic pipes miners have used to stake their claims.

When cavity-nesting birds check out the pipes for a potential nursery, they find a death trap. They can't get enough wing extension to fly out and the pipe is too slick for a toehold to climb out.

A December campaign organized by Nevada wildlife officials knocked down about 23,000 of the pipes and recorded about 9,500 dead birds. One marker alone contained 42 dead birds.

More than 3.4 million of the white PVC pipes are sticking out of the ground across the West, according to the U.S. Bureau of Land Management.

An Idaho Fish and Game Department newsletter recently pointed out some structures, such as outhouses, also trap and kill birds with PVC pipe used for intakes or ventilation. Screening the top of the pipes is a simple fix.

Solutions for the industrial size issues seem beyond the reach of individuals, but we all can find a way to give birds a break.

Keeping dogs on leash in spring is a boon to ground-nesting birds such as quail and ducks.

But a bird-crazy Lab puppy with endless enthusiasm is outmatched as a threat to birds by another common household pet. Even Ted Nugent -- who likes to brag about whacking and stacking big game -- is a carnivore-in-training compared with the average free-roaming cat.

Research on the predatory prowess of house cats and feral cats has been revealing gut-wrenching statistics for years.

The Crittercam Project revealed last year by the National Geographic Society and University of Georgia won the international spotlight by letting cats film their own attacks on birds and other wildlife.

By monitoring video from cameras on cat collars, researchers found that 30 percent of the sampled cats were successful in capturing and killing prey. Those cats averaged about one kill for every 17 hours outdoors.

The kitties brought home only 23 percent of their kills, giving cat owners more room for denial.

People make a lot of excuses for their free-roaming felines, but the camera doesn't lie.

Extrapolating the results across the country and including feral cats, the researchers pegged the national toll of birds killed by cats at more than 500 million.

"Cat predation is one of the reasons why one in three American bird species are in decline," said George Fenwick, American Bird Conservancy president.

But even those startling figures are low, according to new study published in January the Smithsonian Conservation Biology Institute and the U.S. Fish and Wildlife Service.

That research linked cats to an annual death toll of 1.4 to 3.7 billion birds.

The carnage inflicted by outdoor cats may exceed the combination of all other known direct sources of anthropogenic bird and mammal mortality combined, including collisions with windows, buildings, communication towers, vehicles and pesticide poisoning.

Recent shootings and the bombing in Boston have a link with the shocking slaughter of birds: People have a responsibility to address friends or family with a clear disposition for mass violence.

Think about that next time you let kitty out for the day.

Copyright 2014 The Billings Gazette. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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