Reproductive tactics under severe egg predation: an eider's dilemma.

• Parental defence against predators may increase offspring survival but entail other costs. Egg predation is frequent early in the laying sequence of the common eider, which differs in this and in several other ways from most other waterfowl. We test the hypothesis that permanent presence at the nest from the second or third egg is an adaptation for reducing egg predation in eiders. Two other alternative hypotheses for lower predation at later nest stages are early predation loss of the most vulnerable nests and seasonal decrease in predation risk. Analyses of predation rates at the one-egg and later stages refute these two alternatives. Early nest attendance by eider females is estimated to increase clutch survival by about 20% in four-egg and 35% in five-egg clutches, albeit probably at a cost of smaller clutch size.

Ämnesord

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Nyckelord

Animals

Clutch Size

physiology

Ducks

physiology

Female

Nesting Behavior

physiology

Ovum

physiology

Predatory Behavior

physiology

Reproduction

physiology

Egg survival

Laying sequence

Nest predation

Parental defence

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)