Meeting Abstract
Lead exposure has been a major public health concern for decades, but recent research has highlighted the extreme vulnerability of the developing brain to even very low levels of lead. Few experimental studies have directly measured the effects of lead on learning. Songbirds provide an opportunity to examine the impacts of early lead exposure on learning, because they are a model for studying cognition and they learn their songs. In addition to song, many birds possess other condition-dependent traits, such as ornamental coloration, that could be susceptible to lead exposure and like song, have ramifications for future reproductive success. To resolve how lead exposure may impact learning, we reared 40 zebra finches in captivity and exposed them to levels of lead in water within the range reported in Flint, MI [high (1000 ppb, n=12) or moderate (100 ppb, n=16)], or reared them under control conditions (n=12). We then compared the songs of male birds against those of their tutors to assess their vocal learning and evaluated all birds in a motoric and a spatial cognition task. Finally, we measured bill coloration in male birds to infer potential impacts on reproductive success that are independent of song learning. We found that males exposed to lead imitated tutor song less precisely than controls indicating impaired learning. We detected no differences in motoric or spatial learning among treatments but found that males exposed to lead had brighter, yellower beaks than control males. These preliminary data demonstrate that exposure to lead in water compromises subtle measures of song learning and may also impact male attractiveness to females.
