28 September 1999
by Kate Melville
While we worry about airplanes crashing into things most people give little thought to birds. However apparently man made structures are killing off lots of avian types.
Bird scientists gathering at Cornell University last month for the annual American Ornithologists' Union (AOU) meeting looked ahead to the annual fall migration time with dread. Apparently while birds have been hitting man made structures particularly in North America for at least 100 years, there are now many more tall towers, particularly for cellular phone and digital television transmission, with even more on the drawing boards.
To look more closely at this issue Bill Evans, of the Cornell Laboratory of Ornithology organised a scientific conference called, "Avian Mortality at Communications Towers."
According to Evans, "Many of these species face degraded habitats at both ends of their migration flights and the thousands of towers are a new threat along the way,". He estimates that birds collide with manmade objects at the rate of 4 million per year.
Flying will become even more hazardous in the next decade, when television stations convert to the digital format. In the US alone there will be more than 1,000 megatowers, each at least 1,000 feet tall.
In one recent tragedy an estimated 10,000 Lapland longspurs died on a foggy, snowy night in Kansas. The television tower that killed these birds was only 420 feet high.
The Cornell conference brought together, for the first time, biologists from government and academia, environmentalists as well as from the broadcast and communications industries.
While the delegates reached no consensus, they heard plenty of alarming facts:
Large kills almost invariably occur when migrating birds encounter inclement weather along frontal boundaries
Kills are strongly associated with lights on structures
Avian navigation systems might be disrupted by red lights or radio signals that interfere with the birds' ability to monitor Earth's geomagnetic field
There are efforts underway in some countries to address these issues. In Canada there are two interesting programs:
In the first voluntary cutbacks on lighting in tall buildings in downtown Toronto has been shown to save the lives of thousands of birds
In Ontario the as part of F.L.A.P. (Fatal Light Awareness Program), Ontario Hydro replaced spot lights with rapidly flashing strobe lights on emissions stacks at six electrical generation stations. Since then bird collisions have decreased dramatically.
There is some dispute about the total number of birds killed but, experts estimate it could be as many as 100 million birds each year! So while this may not be an enormously topical issue in the general scheme of things it's a good example of where business needs to work more closely and cooperatively with scientists.