Plasticity in nesting adaptations of a tidal marsh endemic bird

If individuals can perceive and manage risks, they may alter their behaviors based on prior experience. This expectation may apply to nest site selection of breeding birds, for which adaptive behavioral responses may enhance fitness. Birds that nest in tidal marshes have adapted to the challenges posed primarily by periodic, monthly tidal flooding and secondarily, by predation. We investigated adaptive responses in nesting behavior of the saltmarsh sparrow (Ammodramus caudacutus), an obligate tidal-marsh-breeding bird, using 536 nests monitored across five years. Using linear mixed effects models, we tested whether nest characteristics differed among nests that were successful, depredated, or flooded, and we investigated if females made changes in nest structure and placement according to outcome of their previous nesting attempt. Nest characteristics differed among females with different nest fates. Fledged and depredated nests were built higher in the vegetation and in higher elevatio...