The Effect of Hemosporidian Infections on White‐Crowned Sparrow Singing Behavior

Relatively little is known about the effects of specific parasites on sexually selected behavioral traits. We subjected free‐living mountain white‐crowned sparrows ( Zonotrichia leucophrys oriantha ) to a playback experiment to identify the effect of hemosporidian parasites on potentially sexually selected song characteristics. We recorded song after a playback of a novel white‐crowned sparrow song, meant to simulate a territorial intrusion. Infections with Leucocytozoon or Plasmodium influenced singing behavior, while infection with Haemoproteus had no detectable effect. Specifically, song consistency, as measured using a spectrogram correlation, was influenced by both Plasmodium and Leucocytozoon infection. Additionally, birds infected with Plasmodium sang fewer songs following experimental playback. Thus, relatively widespread parasites, like Plasmodium , may have a strong effect on potentially sexually selected song characteristics.