Survey of aflatoxin concentrations in wild bird seed purchased in Texas

The use of backyard feeders to attract avian wildlife is a common practice throughout the United States. However, feeding wildlife may create a problem due to aflatoxin, a harmful fungal metabolite, which can affect wildlife that are fed contaminated grain. Our study was initiated to determine if songbirds were being exposed to aflatoxin-contaminated feed throughout Texas. Bags of wild bird seed (n = 142) were purchased from grain cooperatives, grocery stores, and pet shops located in the panhandle, central, south, east, and west regions of Texas during spring and summer 1999. Aflatoxin concentrations in bird seed ranged from non-detectable to 2,780 micrograms/kg. Overall, 17% of samples had aflatoxin concentrations greater than 100 micrograms/kg, of which 83% contained corn as an ingredient. Retail establishment effects were noted in the southern and western regions of Texas, with average concentrations of aflatoxin greater from bags of bird seed purchased from grain cooperatives, followed by pet shops, then grocery stores. Regional differences in aflatoxin levels were not apparent from bags of seed purchased at pet shops: however, regional differences were noted in aflatoxin levels from seeds obtained at grocery stores and grain cooperatives. Average aflatoxin concentration from seed purchased at grocery stores was greatest in the panhandle region, followed by the remaining regions. Within grain cooperatives, the panhandle, south, and west regions of Texas exhibited higher levels of aflatoxin-contaminated bird seed than cooperatives within the east and central regions of Texas. Granivorous songbirds in Texas are exposed to aflatoxins at backyard feeders, which may be a significant morbidity and mortality factor.