Data from: 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
elevation areas of the marsh than those that flooded. Successful nests had
more canopy cover and were comprised of a lower proportion of high marsh
vegetation (Spartina patens) than those that were flooded or depredated.
Females with nests that failed due to flooding constructed subsequent
nests higher in the vegetation and at higher elevation than those that
were successful in their prior attempt, consistent with a response to
previous experience. 85% of females renested within the average core home
range distance (77 m), indicating a high degree of nest placement
fidelity. Females for which nests were depredated in their prior nesting
attempt renested at a greater distance than females for which the previous
nesting attempts were successful. Our findings suggest saltmarsh sparrows
exhibit plasticity in nesting behavior, which may be important for
balancing selective pressures in a dynamic environment. This plasticity,
however, is insufficient to enable them to adapt to the increased flooding
predicted with sea-level rise.