THE status of songbird population worldwide is difficult to determine. Some studies show that songbird populations are declining, but the sources of the problem are difficult to pinpoint. Many scientists attribute the decline in Europe to the invasion of bird habitats by agriculture, building and industrialization, and extraction of raw materials. Pollution and pesticides also contribute. Hunting may not be the major factor, but scientists say there's no doubt it exacerbates the problem.
The practice of shooting songbirds is traditional in many countries, including Italy, Malta, France, Greece, Spain, Turkey, and Portugal.
``Save the Birds'' by Rudolf L. Schreiber and others, an international best-seller published in 12 languages and 16 countries (by Houghton Mifflin in the United States), says that ``alteration of habitats and the pressure of hunting are the two major threats to birds.'' The book's publication spearheads an international ``Save the Birds'' campaign co-founded by Pro Natur in Frankfurt, West Germany, and the International Council for the Preservation of Birds (ICPB) - the oldest conservation organization in the world - located in Cambridge, England.
Recently released statistics drawn from 20 years of breeding-bird surveys conducted by the United States Fish and Wildlife Service show that North American songbirds that migrate to the tropics are declining 1 percent each year. However, some individual species are declining by as much as 40 percent each year.
Data is not nearly as comprehensive for European birds - partly because coordinating a survey among so many countries is difficult, and intensive study is required over a long period.
``There have been studies, mainly in Germany and Austria, that are systematic studies for songbirds,'' says Dr. Tobias Salathe, program officer for migratory birds at the ICPB. ``They actually captured 37 different species and analyzed the data over a period of 10 years,'' he says.
The study found that between 1974 and 1983, 64 percent of the songbirds decreased while 38 percent increased in number. Twenty of the 37 species showed declines.