Blowfly Trypocalliphora braueri (Diptera: Calliphoridae) larvae infestation in willow warblers Phylloscopus trochilus breeding in a hybrid zone.
We examined the occurrence of blowfly larvae Trypocalliphora brauneri in Swedish willow warbler Phylloscopus trochilus nestlings at three nearby breeding sites in Central Sweden. The occurrence of parasites was examined in nestlings by visual inspection during ringing. Larvae were encapsulated in the wings, head, neck, or the sides of the body of the nestlings and caused large swellings. Some of t