The quantitative study of marked individuals in ecology, evolution ...

EURING 2003 Radolfzell
duckling size and condition, and 5) weather. We defined ducklings as belonging to
one of 3 social strata: (A) natal mother with no foster ducklings, (B) foster mother and
conspecific non-siblings, (C) natal mother with conspecific non-siblings and limited
our study of movement probabilities to two weeks after hatch because this period is
when most mortality and movement occurred. Thus, we estimated probabilities of
survival, recapture, and movement for each stratum focusing on covariates for movement.
We evaluate hypotheses suggested to motivate PHBA (e.g., accidental mixing,
brood size and brood success, and energetic stress hypotheses) and evaluate
the influence on duckling survival. Because the importance of predation in motivating
abandonment or adoption of ducklings remains equivocal, we discuss how duckling
traits, in a population located near high gull densities, may provide insights into the
relative importance of predation to PHBA.
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