| 1. |
- Bäckman, Johan, et al.
(författare)
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The influence of fat stores on magnetic orientation in day-migrating Chaffinch, Fringilla coelebs
- 1997
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Ingår i: Ethology. - : Wiley. - 1439-0310 .- 0179-1613. ; 103:3, s. 247-256
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Tidskriftsartikel (refereegranskat)abstract
- Earlier experimental studies have demonstrated the ability of day-migrating birds to perform migration under overcast skies, thereby indicating use of cues other than solar. The orientation behaviour of the chaffinch, a diurnal migrant, was investigated in orientation cage experiments during the autumn migration period. The aim of our experiments was to examine the relationship between different orientation cues and the influence of body condition on directional choices. We obtained the following results: 1. Chaffinches displayed a bimodal distribution of headings along a SW-NE axis when tested in the local geomagnetic field (controls); 2. When the geomagnetic field was experimentally deflected 90° counterclockwise, the chaffinches responded by changing their preferred axial orientation to SE-NW; and 3. The predictive power of stored fat reserves became evident when both the control and experimental samples were subdivided into fat and lean individuals. The majority of fat controls orientated towards a seasonally appropriate SW direction, whereas lean controls chose mean directions towards the NE. Experimentals followed the same pattern, but with the expected deflection, i.e. fat birds selected SE headings and lean individuals chose a NW mean direction.
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| 2. |
- Nilsson, Jan-Åke
(författare)
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Establishment success of experimentally delayed juvenile marsh tits (Parus palustris)
- 1990
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Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 85:1, s. 73-79
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Tidskriftsartikel (refereegranskat)abstract
- By experimentally manipulating the time when young marsh tits, Parus palustris, could become established, I tested the influence of size, hatching date, social dominance in caged situations, and time of season on establishment success. Individuals that managed to become established were divided into two groups: those that became established in new territories and those that were found in the same territory as the one where they were caught. In no circumstances did size, hatching date or social dominance influence establishment success. The only factor tested that had a significant effect on establishment success, was when the juveniles were released; those that established themselves in new territories had been released earlier than unsuccessful ones. Thus, prior occupancy rather than hatching date per se is the factor determining establishment in new territories. Juveniles that became re‐established in their former territory had been released significantly later than those not becoming re‐established. As the season progresses, increasingly fewer unestablished juveniles are present to fill vacancies. Thus, late‐released juveniles stood a better chance of finding their flock position still vacant compared with juveniles released early, whose previous positions would already have been occupied by other juveniles.
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| 3. |
- Sundberg, Jan
(författare)
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Absence Of Mate Guarding In The Yellowhammer (Emberiza-Citrinella)
- 1992
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Ingår i: Ethology. - 0179-1613 .- 1439-0310. ; 92:3, s. 242-256
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Tidskriftsartikel (refereegranskat)abstract
- The mate guarding behaviour of male yellowhammer (Emberiza citrinella) was studied with special reference to the effects of age, body size (tarsus length) and coloration of males. Measurements of intra-pair distance do at the most provide evidence for relatively lax mate guarding. On the other hand, patterns of male song activity and inter-male aggression were more in agreement with the predictions of the mate guarding hypothesis. The reasons for the comparatively low mate guarding intensity in the yellowhammer may be that males do not need to guard their mates intensely. Age differences were found in song and aggressive activity, older males singing and fighting the most. Size had no effect on guarding behaviour. Coloration was correlated with inter-male aggressiveness and conflict initiation propensity. Less colourful males fought the most in the pre-fertile period of their mates, whereas colourful and old males fought the most during the fertile period. This suggests that coloration may be an indicator of individual fighting and guarding ability.
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| 4. |
- MERILA, J, et al.
(författare)
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DO GREAT TITS (PARUS-MAJOR) PREFER ECTOPARASITE-FREE ROOST SITES - AN EXPERIMENT
- 1995
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Ingår i: ETHOLOGY. - : BLACKWELL WISSENSCHAFTS VERLAG GMBH. - 0179-1613. ; 99:1, s. 53-60
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- To investigate whether great tits (Parus major) avoid roosting in flea-(Ceratophyllus sp.) infested nest boxes, roost-site selection in relation to naturally occurring flea numbers was studied in two nest box areas on Gotland, Sweden. In one area (A), eve
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| 5. |
- OLSSON, K, et al.
(författare)
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DO FLEAS, AND/OR OLD NEST MATERIAL, INFLUENCE NEST-SITE PREFERENCE IN HOLE-NESTING PASSERINES
- 1995
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Ingår i: ETHOLOGY. - : BLACKWELL WISSENSCHAFTS VERLAG GMBH. - 0179-1613. ; 101:2, s. 160-170
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- This study examined nest-site choice in a migratory population of pied flycatchers (Ficedula hypoleuca) and sympatric populations of three resident tit species (Parus major, P. caeruleus and P. palustris) in central Sweden. All four species are secondary-
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| 6. |
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| 7. |
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| 8. |
- Pelabon, C, et al.
(författare)
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Social interactions of yearling male fallow deer during rut
- 1999
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Ingår i: ETHOLOGY. - : BLACKWELL WISSENSCHAFTS-VERLAG GMBH. - 0179-1613. ; 105:3, s. 247-258
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Despite a low probability of achieving copulations, yearling male (1.5-year-old) fallow deer Dama dama display behavioural changes during rut, interacting with both females and older males. Juvenile interactions in polygynous ungulates may affect further
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