Diurnal exposure as a risk sensitive behaviour in tawny owls Strix aluco?
(2003) In Journal of Avian Biology 34(4). p.409-418- Abstract
- Tawny owls Strix aluco generally roost in cryptic locations during the day. To test the hypothesis that this cryptic behaviour is an effort to avoid mobbers or avian predators, we measured diurnal behaviour and cause-specific mortality of radio-tagged birds. Non-breeding adults (assumed to be well fed individuals, optimising their own survival) roosted in less exposed locations than adults with young and newly independent juveniles. Parents roosted in the most exposed sites when their young were immature and vulnerable to depredation, probably to guard offspring. Newly independent juveniles apparently selected roosting sites in exposed places to get access to food, as this behaviour was associated with lower perching heights and higher... (More)
- Tawny owls Strix aluco generally roost in cryptic locations during the day. To test the hypothesis that this cryptic behaviour is an effort to avoid mobbers or avian predators, we measured diurnal behaviour and cause-specific mortality of radio-tagged birds. Non-breeding adults (assumed to be well fed individuals, optimising their own survival) roosted in less exposed locations than adults with young and newly independent juveniles. Parents roosted in the most exposed sites when their young were immature and vulnerable to depredation, probably to guard offspring. Newly independent juveniles apparently selected roosting sites in exposed places to get access to food, as this behaviour was associated with lower perching heights and higher prey abundance beneath their roosting sites. They also perched in more exposed sites, closer to the ground, in summers with low prey abundance compared to summers with high prey abundance. After previous encounters with goshawks Accipiter gentilis, dependent juveniles roosted in less exposed places compared to other young. The increased risk of being mobbed was highly significant with increasing roosting exposure. Once an owl was mobbed, the intensity of the mobbing correlated positively with the mass of the mobbers, but mobbing birds never killed any owls. In contrast, diurnal raptors caused 73% of natural owl deaths (n = 15) and the depredation rate by raptors was 3.8 times higher in population classes that generally roosted in more exposed locations than did non-breeding adults. We therefore suggest that depredation by diurnal raptors is the main factor shaping the diurnal behaviour of tawny owls. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/137090
- author
- Sunde, Peter LU ; Bolstad, M S and Desfor, K B
- organization
- publishing date
- 2003
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Journal of Avian Biology
- volume
- 34
- issue
- 4
- pages
- 409 - 418
- publisher
- Wiley-Blackwell
- external identifiers
-
- wos:000187792000015
- scopus:0346009376
- ISSN
- 0908-8857
- DOI
- 10.1111/j.0908-8857.2003.03105.x
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Animal Ecology (Closed 2011) (011012001)
- id
- b2b48a11-4a14-4359-b3df-e95e6e013401 (old id 137090)
- date added to LUP
- 2016-04-01 12:20:59
- date last changed
- 2022-02-26 05:55:11
@article{b2b48a11-4a14-4359-b3df-e95e6e013401,
abstract = {{Tawny owls Strix aluco generally roost in cryptic locations during the day. To test the hypothesis that this cryptic behaviour is an effort to avoid mobbers or avian predators, we measured diurnal behaviour and cause-specific mortality of radio-tagged birds. Non-breeding adults (assumed to be well fed individuals, optimising their own survival) roosted in less exposed locations than adults with young and newly independent juveniles. Parents roosted in the most exposed sites when their young were immature and vulnerable to depredation, probably to guard offspring. Newly independent juveniles apparently selected roosting sites in exposed places to get access to food, as this behaviour was associated with lower perching heights and higher prey abundance beneath their roosting sites. They also perched in more exposed sites, closer to the ground, in summers with low prey abundance compared to summers with high prey abundance. After previous encounters with goshawks Accipiter gentilis, dependent juveniles roosted in less exposed places compared to other young. The increased risk of being mobbed was highly significant with increasing roosting exposure. Once an owl was mobbed, the intensity of the mobbing correlated positively with the mass of the mobbers, but mobbing birds never killed any owls. In contrast, diurnal raptors caused 73% of natural owl deaths (n = 15) and the depredation rate by raptors was 3.8 times higher in population classes that generally roosted in more exposed locations than did non-breeding adults. We therefore suggest that depredation by diurnal raptors is the main factor shaping the diurnal behaviour of tawny owls.}},
author = {{Sunde, Peter and Bolstad, M S and Desfor, K B}},
issn = {{0908-8857}},
language = {{eng}},
number = {{4}},
pages = {{409--418}},
publisher = {{Wiley-Blackwell}},
series = {{Journal of Avian Biology}},
title = {{Diurnal exposure as a risk sensitive behaviour in tawny owls Strix aluco?}},
url = {{https://lup.lub.lu.se/search/files/2887276/624634.pdf}},
doi = {{10.1111/j.0908-8857.2003.03105.x}},
volume = {{34}},
year = {{2003}},
}