Direct and Indirect Effects of the El Niño Southern Oscillation on Development and Survival of Young of a Tropical Passerine

The El Niño Southern Oscillation (ENSO) is a global phenomenon that influences climate variation and, in turn, the ecological processes affecting the abundance and distribution of populations across taxa. For example, the ENSO can profoundly influence the development and survival of pelagic species, but the extent to which the ENSO affects offspring of terrestrial species is less well known. We used piecewise structural equation modeling to investigate the direct and indirect relationship between the ENSO and offspring development and survival in a terrestrial tropical passerine, the lance-tailed manakin (Chiroxiphia lanceolata). The Oceanic Niño Index (ONI), a measure of the ENSO, was negatively related to individual growth rate, maximum number of lesion developed by nestlings, and hatching day-of-year; which in turn mediated indirect effects on fledging success and recruitment. Further the ONI was a better predictor of nestling development compared to local temperature and rainfall. Our study establishes a link between the ENSO and the development and survival of young of a terrestrial species and underscores the need to better understand how offspring cope with global climate variation.