Provisioning response to manipulation of apparent predation danger by parental Pied Flycatchers
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| Authors: | Hakkarainen, H; Yli-Tuomi, I; Korpimaki, E; Ydenberg, R |
| Year: | 2002 |
| Journal: | Ornis Fennica 79: 139-144 |
| Title: | Provisioning response to manipulation of apparent predation danger by parental Pied Flycatchers |
| Abstract: | We tested whether nest visitation rate of parent Pied Flycatchers (Ficedula hypoleuca) is decreased by an experimentally increased predation risk. We simulated predation risk by placing a stuffed Pygmy Owl (Glaucidium passerinum) in the nest vicinity and by playback of pygmy owl's whistling. We used Blackbird (Turdus merula) treatment as a control. Surprisingly, the parental nest visitation rate was about 25% higher in the treatment than in the control group. The treatments were reversed on the same day. Pairs of the "control treatment" in the first phase increased their nest visitation rate by 16% as a response to the "owl treatment". Four possible explanations exist. Parents may increase delivery in order (1) to silence the begging of the nestlings, who might otherwise betray the nest location to the owl, or (2) to increase the growth rate of the nestlings so that they fledge sooner, probably disperse better and so elude the danger. Alternatively, (3) the parents may view a predator as a threat to themselves, and remain in the vicinity of the nest where they are most familiar and therefore safest. In addition, (4) increased nest visitation might form part of nest defense behaviour against the owl. |
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