Pigweed (Amaranthus spp) (IMAGE) Cambridge University Press Caption Many pigweed species (Amaranthus spp.) have been found as contaminants in commercially available bird feed mixes. Pigweeds were found at an average of 384 seeds kg-1 but reached levels as high as 6,525 seeds kg-1. This photo shows a variety of pigweed species that germinated following extraction from commercial bird feed mixes. Photo credit: Mindy Ward of Penton Media Credit Photo credit: Mindy Ward of Penton Media Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.