Callan, L. M., F. A. La Sorte, T. E. Martin, and V. G. Rohwer. 2019. Higher nest predation favors rapid fledging at the cost of plumage quality in nestling birds. American Naturalist 193: 717-724.
Life-history theory predicts that rapid growth comes at a cost to trait quality or adult longevity. However, this predicted trade-off has been weak or absent in passerine birds that vary in their growth rates. Trade-offs associated with fast growth and short development time might be better expressed in ephemeral traits because costs associated with these traits can be recovered or eliminated when they are replaced. We examined whether shorter development time yielded lower quality nestling body feathers, an ephemeral trait. We found a strong trade-off whereby nestlings that spend more time in the nest growing slowly produced higher quality plumage across 123 temperate and tropical species. This trade-off appears largely driven by nest predation because high predation rates favor rapid nestling growth and short development times at the cost of plumage quality. Our results suggest that ephemeral traits, like nestling body feathers, which can be replaced later, have the potential to minimize other longer-term trade-offs that arise during the rapid development of multiple traits.