A1 Refereed original research article in a scientific journal
Reproduction and survival in a variable environment: Ural owls (Strix uralensis) and the three-year vole cycle
Authors: Brommer JE, Pietiainen H, Kolunen H
Publisher: AMER ORNITHOLOGISTS UNION
Publication year: 2002
Journal:Auk
Journal name in sourceAUK
Journal acronym: AUK
Volume: 119
Issue: 2
First page : 544
Last page: 550
Number of pages: 7
ISSN: 0004-8038
DOI: https://doi.org/10.1642/0004-8038(2002)119[0544:RASIAV]2.0.CO;2
Abstract
We analyzed data oil 535 Ural Owl (Strix uralensis) breeding attempts and consecutive survival of both adults arid offspring from 1987-1998 in relation to the regional abundance of the Ural Owl's main prey, voles, which show a cycle of low, increase, and peak phases in their population numbers. Vole abundance varied tip to 49X, crashing during spring-summer every three years. The breeding population tracked abundance of voles in the previous autumn with respect to percentage of pairs breeding and their reproductive output (having date, clutch size), largely irrespective of phase. Survival depended on vote density in the preceding autumn, but was generally highest in the increase phase. There was thus a paradoxical situation in the peak phases, when vote populations crashed; the owls produced large clutches, but those survived poorly. Some adaptive and nonadaptive scenarios of the Ural Owl's life history are discussed.
We analyzed data oil 535 Ural Owl (Strix uralensis) breeding attempts and consecutive survival of both adults arid offspring from 1987-1998 in relation to the regional abundance of the Ural Owl's main prey, voles, which show a cycle of low, increase, and peak phases in their population numbers. Vole abundance varied tip to 49X, crashing during spring-summer every three years. The breeding population tracked abundance of voles in the previous autumn with respect to percentage of pairs breeding and their reproductive output (having date, clutch size), largely irrespective of phase. Survival depended on vote density in the preceding autumn, but was generally highest in the increase phase. There was thus a paradoxical situation in the peak phases, when vote populations crashed; the owls produced large clutches, but those survived poorly. Some adaptive and nonadaptive scenarios of the Ural Owl's life history are discussed.
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