Breeding-bird censuses conducted in 1994-1996 at the Santa Ana National Wildlife, southern Texas were compared to those done on the same site in 1973-1978. The study site was described as subtropical evergreen forest in the 1970s, but is now thorn-forest with remnant evergreen forest. Canopy cover was incomplete and lower and trees were smaller and more densely packed in 1994-1996 than in 1973-1978. Seven bird species typical of thorn-forest and thorn-scrub, which were not present in 1973-1978, made up 20% of the breeding bird community in 1994-1996. Species tolerant of thorn-forest and thorn-scrub made up 76.0% of the breeding bird community in 1994-1996, compared to 54.6% in 1973-1978. Three forest bird species disappeared from the study site. Water management will be needed if subtropical evergreen forest and its bird community are to be restored.
Brush, T., & Cantu, A. (1998). Changes in the breeding bird community of subtropical evergreen forest in the lower Rio Grande Valley of Texas, 1970s-1990s. Texas Journal of Science, 50(2), 123–132.
Texas Journal of Science