Abstract
Naturalists were appalled recently when employees of a television station at Springfield, Illinois, the high tower of which was near the Sangamon River, picked up 827 dead or crippled birds one morning near the high mast.
In this huge slaughter of migrating birds, 40 species were identified, the six most numerous being the grey-cheeked and Swainson's thrushes, red-eyed vireos, ovenbirds and the Tennessee and chestnut-sided warblers.
Then a second kill at this same television mast chalked up 219 dead birds. Later, the third kill snuffed out the lives of over 1,100 song birds. It is significant to note that all of these bird kills occurred in September.
Why the mass suicide of our song birds?
There are a number of reasons, most of them made by man.
Birds a-wing on migratory flights run into foul weather, much as humans do on the highways. Lighthouses, tall buildings, monuments, tall radio and TV masts and microwave towers all are traps to flocks of night-flying birds. They fly into the structures in storms, usually in the dead of night, and because they fly at great speed, death usually results.
Evidently this is a wildlife tragedy that at the moment has no answer.
The mystery of bird migration has always fascinated bird lovers. The little purple martin flies over two thousand miles to South America for the winter. The seasonal flight of birds in migration is one of the great phenomenon of nature. But now man has added his own obstacles in the form of high buildings, towers and communication aerials, into which the birds get entangled.
Why do certain high structures in the nation never have a bird-kill? The frequency of these bird-kills take place only on the migratory routes used by birds, year after year. One path of migration, called a flyway, follows roughly the Mississippi river, and any barricades built in this path has birdkills far too often for the consciences of naturalists.
Weather also plays its part. The rapidly-flying flocks of migratory birds
moving at night with the southwardflow ing air mass, sometimes lose altitude during periods of a low cloud base. Add to this condition heavy haze, smog or fog, and the birds start 'committing suicide.' Evidently they do not see the obstacles in their flight path, or if they do, not in time to avoid mass collisions. Study of these unusual birdkills show that the death toll is always highest during some adverse weather flareup, wind or storm.
A bird mortality count kept at Washington Monument, Washington, D.C. from 1936 through 1938 showed an average kill of 328, with a freak kill one single night that totalled 576 birds, representing 24 species.
In contrast, the bird-kill at the Gateway Arch at Saint Louis, one of the highest structures in the area, is comparatively low.
High bird-kills have been reported at the Empire State building and other skyscrapers in New York City. A TV mast near the Mississippi flood plain in Wisconsin racked up nearly 20,000 dead birds in a single year' A similiar tower in Florida annually kills 2,500 birds, a matter of statistical record. Multiply this by about 550 towers in migratory flyways and one comes up with a staggering total of dead birds.
Regardless of the deep concern of naturalists and the informed public, there does not seem to be any way to prevent these tragedies to our song birds.
Despite the efforts of countless Americans to preserve the little purple martin, building houses for it in staggering numbers, scientists say the bird is barely holding its own in number.
Our great grandfathers knew the passenger pigeon as one of America's most prolific birds, literally blacking the sky on migration routes. But the last passenger pigeon died in 1914 due to man's ruthlessness.
Today, by the same token, man's progress, his skyscrapers, monuments and towers are destroying birds en masse. Seemingly there is no answer to the problem. The migration routes are always the same, and as time passes, there will be more and more hazards confronting our wildlife.
Even if man cleans up his environment, cutting down the pollution-kill of things of the wild, the perils in the sky will never be diminished. It's a sobering thought to people who love all winged creatures. •