Birds of prey and grouse in Finland:do avian predators limit or regulate their prey numbers?
Abstract Relationships between predators and prey may affect population dynamics of both parties. Predators may also serve as a link between populations of different prey, e.g., small game and small mammals. I used available data on the diet and reproduction of birds of prey (mainly common buzzards...
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University of Oulu
2008
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ftunivoulu:oai:oulu.fi:isbn978-951-42-8805-0 2023-07-30T03:55:23+02:00 Birds of prey and grouse in Finland:do avian predators limit or regulate their prey numbers? Reif, V. (Vitali) 2008-05-28 application/pdf http://urn.fi/urn:isbn:9789514288050 eng eng University of Oulu info:eu-repo/semantics/altIdentifier/pissn/0355-3191 info:eu-repo/semantics/altIdentifier/eissn/1796-220X info:eu-repo/semantics/openAccess © University of Oulu, 2008 birds of prey functional response grouse numerical response population dynamics predation small mammals info:eu-repo/semantics/doctoralThesis info:eu-repo/semantics/publishedVersion 2008 ftunivoulu 2023-07-08T20:01:34Z Abstract Relationships between predators and prey may affect population dynamics of both parties. Predators may also serve as a link between populations of different prey, e.g., small game and small mammals. I used available data on the diet and reproduction of birds of prey (mainly common buzzards Buteo buteo and goshawks Accipiter gentilis) and video surveillance of their nests, as well as multiannual data on numbers of grouse and small mammals for studying food habits and population dynamics of raptors and their links with population fluctuations of voles and grouse (capercaillie Tetrao urogallus, black grouse Tetrao tetrix and hazel grouse Bonasa bonasia) in western Finland during 1980–1990s when grouse and vole numbers fluctuated in regular cycles. Microtus voles were the main prey of the buzzards which partly switched their diet to small game (juvenile grouse and hares) in years when vole numbers declined. The nesting rate of buzzards also correlated with vole abundance, but the productivity rate and brood size tended to lag behind the vole cycle. This mismatch between the buzzards’ functional and numerical responses resulted in a fairly small impact of buzzards on juvenile grouse, which did not correlate with vole density. The productivity of goshawks followed the fluctuations of grouse density closely whereas the occupancy rate of goshawk territories did so with a two-year lag. The annual numerical ratio of goshawk to grouse was inversely related to grouse density, suggesting that this predator may be a destabilising factor for grouse population dynamics. However, the goshawks’ kill rate of grouse showed no clear relations to grouse density. In June–July, these birds of prey (including hen harriers Circus cyaneus) usually killed a relatively small number of grouse chicks. Losses to raptors constituted up to one quarter of grouse juvenile mortality during the two months. We did not find a strong effect of avian predators on grouse juvenile mortality. In boreal forests, predators and other factors of ... Doctoral or Postdoctoral Thesis Accipiter gentilis Circus cyaneus Jultika - University of Oulu repository Hen ENVELOPE(-64.914,-64.914,61.317,61.317) |
institution |
Open Polar |
collection |
Jultika - University of Oulu repository |
op_collection_id |
ftunivoulu |
language |
English |
topic |
birds of prey functional response grouse numerical response population dynamics predation small mammals |
spellingShingle |
birds of prey functional response grouse numerical response population dynamics predation small mammals Reif, V. (Vitali) Birds of prey and grouse in Finland:do avian predators limit or regulate their prey numbers? |
topic_facet |
birds of prey functional response grouse numerical response population dynamics predation small mammals |
description |
Abstract Relationships between predators and prey may affect population dynamics of both parties. Predators may also serve as a link between populations of different prey, e.g., small game and small mammals. I used available data on the diet and reproduction of birds of prey (mainly common buzzards Buteo buteo and goshawks Accipiter gentilis) and video surveillance of their nests, as well as multiannual data on numbers of grouse and small mammals for studying food habits and population dynamics of raptors and their links with population fluctuations of voles and grouse (capercaillie Tetrao urogallus, black grouse Tetrao tetrix and hazel grouse Bonasa bonasia) in western Finland during 1980–1990s when grouse and vole numbers fluctuated in regular cycles. Microtus voles were the main prey of the buzzards which partly switched their diet to small game (juvenile grouse and hares) in years when vole numbers declined. The nesting rate of buzzards also correlated with vole abundance, but the productivity rate and brood size tended to lag behind the vole cycle. This mismatch between the buzzards’ functional and numerical responses resulted in a fairly small impact of buzzards on juvenile grouse, which did not correlate with vole density. The productivity of goshawks followed the fluctuations of grouse density closely whereas the occupancy rate of goshawk territories did so with a two-year lag. The annual numerical ratio of goshawk to grouse was inversely related to grouse density, suggesting that this predator may be a destabilising factor for grouse population dynamics. However, the goshawks’ kill rate of grouse showed no clear relations to grouse density. In June–July, these birds of prey (including hen harriers Circus cyaneus) usually killed a relatively small number of grouse chicks. Losses to raptors constituted up to one quarter of grouse juvenile mortality during the two months. We did not find a strong effect of avian predators on grouse juvenile mortality. In boreal forests, predators and other factors of ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Reif, V. (Vitali) |
author_facet |
Reif, V. (Vitali) |
author_sort |
Reif, V. (Vitali) |
title |
Birds of prey and grouse in Finland:do avian predators limit or regulate their prey numbers? |
title_short |
Birds of prey and grouse in Finland:do avian predators limit or regulate their prey numbers? |
title_full |
Birds of prey and grouse in Finland:do avian predators limit or regulate their prey numbers? |
title_fullStr |
Birds of prey and grouse in Finland:do avian predators limit or regulate their prey numbers? |
title_full_unstemmed |
Birds of prey and grouse in Finland:do avian predators limit or regulate their prey numbers? |
title_sort |
birds of prey and grouse in finland:do avian predators limit or regulate their prey numbers? |
publisher |
University of Oulu |
publishDate |
2008 |
url |
http://urn.fi/urn:isbn:9789514288050 |
long_lat |
ENVELOPE(-64.914,-64.914,61.317,61.317) |
geographic |
Hen |
geographic_facet |
Hen |
genre |
Accipiter gentilis Circus cyaneus |
genre_facet |
Accipiter gentilis Circus cyaneus |
op_relation |
info:eu-repo/semantics/altIdentifier/pissn/0355-3191 info:eu-repo/semantics/altIdentifier/eissn/1796-220X |
op_rights |
info:eu-repo/semantics/openAccess © University of Oulu, 2008 |
_version_ |
1772809892068851712 |