Early-life patterns of growth are linked to levels of phenotypic trait covariance and postfledging mortality across avian species

Loren Merrill, Todd M. Jones, Jeffrey D. Brawn, Michael P. Ward

Research output: Contribution to journalArticlepeer-review


Life history studies have established that trade-offs between growth and survival are common both within and among species. Identifying the factor(s) that mediate this trade-off has proven difficult, however, especially at the among-species level. In this study, we examined a series of potentially interrelated traits in a community of temperate-zone passerine birds to help understand the putative causes and consequences of variation in early-life growth among species. First, we examined whether nest predation risk (a proven driver of interspecific variation in growth and development rates) was correlated with species-level patterns of incubation duration and nestling period length. We then assessed whether proxies for growth rate covaried with mean trait covariance strength (i.e., phenotypic correlations (rp), which can be a marker of early-life stress) among body mass, tarsus length, and wing length at fledging. Finally, we examined whether trait covariance strength at fledging was related to postfledging survival. We found that higher nest predation risk was correlated with faster skeletal growth and that our proxies for growth corresponded with increased trait covariance strength (rp), which subsequently, correlated with higher mortality in the next life stage (postfledging period). These results provide an indication that extrinsic pressures (nest predation) impact rates of growth, and that there are costs of rapid growth across species, expressed as higher mean rp and elevated postfledging mortality. The link between higher levels of trait covariance at fledging and increased mortality is unclear, but increased trait covariance strength may reflect reduced phenotypic flexibility (i.e., phenotypic canalization), which may limit an organism's capacity for coping with environmental or ecological variability.

Original languageEnglish (US)
Pages (from-to)15695-15707
Number of pages13
JournalEcology and Evolution
Issue number22
StatePublished - Nov 2021


  • canalization
  • developmental flexibility
  • early-life stress
  • nest predation
  • phenotypic correlation
  • trait covariance

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Nature and Landscape Conservation


Dive into the research topics of 'Early-life patterns of growth are linked to levels of phenotypic trait covariance and postfledging mortality across avian species'. Together they form a unique fingerprint.

Cite this