Pollution may make birds change their tune
Mar 07,2008 00:00 by Bend_Weekly_News_Sources

Nothing like a bird chirp­ing in the morn­ing to re­mind you of nature’s glory, right?

Not quite. A rather creepy new re­search find­ing sug­gests some bird songs are a bit un­natur­al—in­flu­enced by pol­lut­ants, which cause at least one species of birds to change their songs.

The European Starling. Stumus Vulgaris. Courtesy Wash. Dept. of Fish & Wildlife

It’s the latest of a number of studies to note that some of pol­lu­tion’s bi­o­log­i­cal ef­fects are not only un­healthy, but bi­zarre. Stud­ies have found con­tam­i­nants caus­ing sex changes, for ex­am­ple, or even pos­sibly rais­ing su­i­cide and child abuse rates.

In the bird study, in­t­er­est­ing­ly, re­search­ers found that the re­vised, more ela­bor­ate tunes were ap­peal­ing to female birds. But the af­fect­ed birds also suf­fered weak im­mune sys­tems, the in­vest­i­gat­ors said.

The sci­en­tists stud­ied male Eu­ro­pe­an star­lings, Stu­mus vul­garis, feed­ing on earth­worms at a sew­age treat­ment works in the south­west U.K. Many of the worms were found to be con­tam­i­nated with chem­i­cals si­m­i­lar to es­tro­gen, a hor­mone in­volved in the de­vel­op­ment of sex­u­al char­ac­ter­is­tics.

Af­fect­ed male birds showed marked changes in brain and behavior, in­clud­ing more com­plex songs, which females pre­ferred, the re­search­ers said. And a brain ar­ea re­spon­si­ble for song com­plex­ity, called the high vo­cal cen­tre, was al­so found to be en­larged in the males.

This re­gion is par­tic­u­larly sen­si­tive to es­tro­gen, which is known to cause “mas­culi­niza­t­ion” of the song­bird brain, ac­cord­ing to the re­search team. The stu­dy, by Kath­er­ine Bu­chan­an of Car­diff Uni­ver­s­ity in the U.K. and col­leagues, ap­peared Feb. 27 in the re­search jour­nal PLoS One.

Courtesy Public Library of Science and World Science staff