Habitat Effects On Monthly Foods Of Bullfrogs In Eastern Texas

A bullfrog food habit study was conducted during 1969 in Nacogdoches County, Texas. Frogs were collected from two diverse vegetational types: (1) open habitat (farm ponds, lakes, and areas void of trees) and (2) wooded habitat (ponds, lakes, and river bottoms in heavily forested areas). There were 55 animal groups and 12 plant groups represented as food items in open habitat samples and 65 ani. mal groups and 20 plant groups in wooded habitat. Total volume of food consumed by all frogs was greater in open habitat than in wooded, however, volume of plant matter consumed was greater in wooded than in open. Crayfish were the main food item consumed, forming over 60 percent by volume in open habitat and over 40 percent by volume in wooded habitat. There was a positive correlation between volume of food consumed and percent crayfish in the diet but a negative correlation between percent insects and volume of food. Amphibians, reptiles, insects, and miscellaneous invertebrates composed the remainder of the diet. The much greater food volume of amphibians, reptiles, and plant materials consumed in wooded habitat and the larger consumption of crayfish in open habitat marked the greatest variations between habitats. Food habits in both habitats varied significantly throughout the study; due mainly to variations in availability of foods. Crayfish and recently metamorphosed bullfrogs were the only examples of gorging on locally abundant foods by bullfrogs. Crayfish, however, were almost absent in bullfrog diets in both habitats during late summer and fall. Amphibians comprised a large percentage of bullfrog diets during this period when crayfish were not taken.

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