Observations Of Imported Fire Ant Predation On Nestling Cottontails

During a five year study of cottontail reproduction in Alabama, frequent observations were made of activities and mortality of nestling cottontail rabbits in five 50' x 50' pens, in six 200' x 200' pens, and in five large enclosures ranging from 6 to 40 acres in size. During this study 371 cottontail nests were found in which 231 litters were born. Evidence, some of which is circumstantial, indicates that 68 whole litters and parts of two other litters were destroyed by fire ants. From these observations it appears that significant fire ant disturbances to cottontail nesting can be expected in pens and enclosures where fire ant populations are of medium to high density. This is not meant to imply that fire ant predation would seriously alter cottontail populations in an unrestricted natural environment containing fire ant populations. Where fire ant populations are considered to be of medium to high density, the data indicates that predation on cottontail nests is not related to proximity of the nest to active fire ant mounds. No fire ant predation was observed in nesting cottontails older than seven days. Field tests in which fire ants were introduced into cottontail nests and into simulated nests of white rats indicated that cottontails reaching pelage development characteristic of approximately four days of age were relatively free from fire ant disturbances. The guard hairs on the back, neck, and head prevented the fire ants from inserting their stingers into these critical areas. Nest construction, particularly the amount and distribution of the fur lining in the nest, appeared significant in preventing mortalities in nestling cottontails. With the possible exception of intensity managed rabbit enclosures, fire ant control measures are not recommended. No indications of fire ant predation were found in 7 active litters and in 18 old nests of cottonrats located incidental to the study. Ant predation on various species of wildlife and fish has been a subject of interest and concern to many writers. Numerous studies (Stoddard, 1931 :139, Travis 1938 :705-708, Moore 1940 :37-42, Schillinger and Morley 1942 :31, Emlen and Glading 1945 :45-46, and Lehmann 1946: 111-123) have resulted in reports of ant disturbances to bird nesting activities. The ants usually involved belonged to the genus Solenopsis, and there were conflicting opinions regarding the damage these ants caused.

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