Does predation danger on southward migration curtail parental investment by female western sandpipers?
Theory predicts that if extending parental care delays migratory departure, and if later migration is more dangerous, then parental care should be curtailed to make an earlier departure. Adult western sandpipers (Calidris mauri) depart Alaska in July, and the presence of peregrine falcons (Falco per...
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| Format: | article |
| Langue: | EN |
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De Gruyter
2015
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| Accès en ligne: | https://doaj.org/article/e7e5e1b8b47b40ab977715e4ea8ba39f |
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| Résumé: | Theory predicts that if extending parental care
delays migratory departure, and if later migration is
more dangerous, then parental care should be curtailed
to make an earlier departure. Adult western sandpipers
(Calidris mauri) depart Alaska in July, and the presence
of peregrine falcons (Falco peregrinus) along their route
rises steeply during the migratory period. Pacific dunlins
(C. alpina pacifica) are ecologically similar, but do not
depart Alaska until October, after peregrine passage
has peaked. Because peregrine migration begins earlier
in years with early snowmelt, we predicted that the
curtailment of parental investment by western sandpiper,
but not of Pacific dunlins, should be more pronounced
in these more dangerous years. We measured breeding
phenology of these species on the Yukon Delta National
Wildlife Refuge during three seasons with strongly
differing snowmelt timing. We found that they initiated
breeding simultaneously, and that western sandpipers,
but not Pacific dunlins, ceased laying increasingly earlier,
provided increasingly less parental care and departed
increasingly sooner as snowmelt was earlier. Advancing
departure date by the overall average of 5.2d relative to
dunlin reduces migratory exposure to peregrines by an
estimated 18%. Our results support the hypothesis that
natural selection has favored curtailment of parental
investment by western sandpipers to advance migratory
departure. |
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