Wrong Thinking

The letter by Robert and Mary Ann Melvin (May 3) concerning the Bell’s vireo represents the kind of scientific naivete that can hinder the efforts of genuine conservation biologists. Caltrans, through its cowbird control program, is helping a species that they have hurt by carelessly choosing their construction sites. The trade is uneven and habitat destruction is irreversible, but the cowbird program is better than nothing.

The Melvins wrote that “never has one wild species eliminated another. Only man can do that.” Millions of species have arisen and departed since life began about 3.5 billion years ago. Until a few tens of thousands of years ago, man had little or no control in extinction. Major causes include climatic and sea-level change and continental drift. Biotic interactions such as predation and competition have also had important roles in both speciation and extinction. The extinction of a species through biotic interactions with another is a natural process.

The cowbird’s importance, then, is magnified because the Bell’s vireo population is small. In addition, the adaptation process mentioned by the Melvins is not an instant phenomenon. Rather than complaining, we should support Caltrans’ cowbird program and act to prevent future vireo habitat destruction.

JOHN CANTILLI

San Diego