Commentator Ron Lambert claims that the threat to wildlife presented by cats is based on unscientific methodologies ("Cats can be managed in a way that protects birds," March 2).
Contrary to his assertion, a review of scientific literature published in January concluded that cats in the U.S. killed as many as 3.7 billion birds and 17 billion mammals every year, and that free-roaming cats may constitute the single greatest man-made cause of wildlife mortality.
Several recent studies show that trap-neuter-release colonies do not lower cat populations. In one Florida example, the number of cats increased from 920 to 983 in just nine months. Immigration causes the colonies to grow.
Cats become concentrated in these colonies with a resulting negative impact on wildlife. We encourage everyone to review the scientific literature on birds and their predators — cats in particular.
Kurt R. Schwarz
The writer is the conservation chairman of the Maryland Ornithological Society.