Sub-lethal effects of permethrin exposure on a passerine: Implications for managing ectoparasites in wild bird nests

Mariana Bulgarella, Sarah Knutie, Margaret A. Voss, Francesca Cunninghame, Brittany Florence-Bennett, Gemma Robson, Robert Keyzers, Lauren Taylor, Phil Lester, George Heimpel, Charlotte Causton

Research output: Contribution to journalArticle


Pyrethroids are commonly used for parasitic insect control in bird nests. We present the first formal evaluation of the effects of continued permethrin exposure on the reproductive success of a passerine, the zebra finch (Taeniopygia guttata), for two generations. We experimentally treated all nesting material with a 1% permethrin solution or a water control and provided the material to breeding finches for nest building. The health of two consecutive clutches produced by the parental generation and one clutch produced by first-generation birds were tracked. Finches in the first generation were able to reproduce and fledge offspring after permethrin exposure, ruling out infertility. Permethrin treatment had no statistically significant effect on the number of eggs laid, incubation time, egg hatch rate, fledgling mass or nestling sex ratio in either generation. However, the treatment of nesting materials with permethrin significantly increased the number of hatchlings in the first generation, and decreased fledgling success in the second generation. Moreover, body mass on hatching was significantly lower and the growth rate was slower for nestlings exposed to permethrin than for the control nestlings for both generations. Permethrin treatment had no effect on liver function tests for any generation. In addition, permethrin accumulated inside non-embryonated eggs. Overall, results suggest a negative effect of permethrin from generation to generation. Although we recommend caution when using this insecticide to eliminate ectoparasites, we also suggest that treating nests with low concentrations of permethrin provides a necessary, stop-gap measure to prevent the imminent extinction of species of conservation concern.
Original languageEnglish (US)
Number of pages33
JournalJournal of Experimental Biology
Issue number1
StatePublished - Sep 8 2020


  • birds
  • nest parasites
  • permethrin
  • reproductive success
  • zebra finch

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