Spatial and temporal patterns of brown rat (Rattus norvegicus) abundance variation in poultry farms

The temporal and spatial patterns of rat abundance variations were studied, and which factors might affect these patterns in poultry farms. Forty-eight poultry farms were sampled from spring 1999 to winter 2001 in Buenos Aires, Argentina. Environmental variables of farms, meteorological variables and distances among farms were registered to evaluate a possible association with rat abundance estimated by trap success. Rattus norvegicus was the dominant rat species in the study area. Rat abundance did not vary temporally and there was reproduction at all times. Trap success was more similar among neighboured farms than among farms further apart. Contrary to the abundance of other small rodents, rat abundance was not significantly related to farm characteristics. The lack of coincidence between rats and other small rodents suggests the existence of a differential response of rats to environmental factors of the poultry farms.