| 1. |
- Klaassen, M, et al.
(författare)
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Flight costs and fuel composition of a bird migrating in a wind tunnel
- 2000
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Ingår i: The Condor: ornithological applications. - 0010-5422. ; 102:2, s. 444-451
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Tidskriftsartikel (refereegranskat)abstract
- We studied the energy and protein balance of a Thrush Nightingale Luscinia luscinia, a small long-distance migrant, during repeated 12-hr long Eights in a wind tunnel and during subsequent two-day fueling periods. From the energy budgets we estimated the power requirements for migratory flight in this 26 g bird at 1.91 Watts. This is low compared to flight cost estimates in birds of similar mass and with similar wing shape. This suggests that power requirements for migratory flight are lower than the power requirements for nonmigratory Eight. From excreta production during Right, and nitrogen and energy balance during subsequent fueling, the dry protein proportion of stores was estimated to be around 10%. A net catabolism of protein during migratory flight along with that of fat may reflect a physiologically inevitable process, a means of providing extra water to counteract dehydration, a production of uric acid for anti-oxidative purposes, and adaptive changes in the size of Eight muscles and digestive organs in the exercising animal.
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| 2. |
- Lillandt, B G, et al.
(författare)
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Family structure in the Siberian Jay as revealed by microsatellite analyses
- 2003
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Ingår i: The Condor: ornithological applications. - 0010-5422. ; 105:3, s. 505-514
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Tidskriftsartikel (refereegranskat)abstract
- The Siberian Jay (Perisoreus infaustus) lives in resident, territorial family groups outside the breeding season, but does not breed cooperatively. Thereby it offers an opportunity to study the evolution of territorial group living, without confounding effects of reproductive cooperation. During a long-term study in Finland 1974-2000, we observed Siberian Jay group composition in autumn. Using microsatellite analysis based on feather or blood samples we clarified kin relations within the groups. We found that out of 311 groups that included at least one more individual than the territory holders, 74% were nuclear families, including breeding birds and 1-3 retained offspring. However, 26% of the groups were not families, but consisted of pairs accompanied only by individuals that were not their offspring. According to extensive pedigrees we found that 70% of the 82 immatures associated with a nonparent pair were not related to either territory holder. Of these 82 immatures, 91% were associated with pairs that had no offspring on their own, suggesting that they were failed breeders or newly established pairs. The composition of groups was mostly unchanged during the observation period within each season, regardless of kinship. Previous studies have reported apparent nepotism between parents and retained offspring in the Siberian Jay, and a high degree of aggression toward nonoffspring, so we did not expect to find such high frequency and remarkable within-season stability of nonfamily groups. These observations suggest that there are important fitness benefits to gain from territoriality and group living, regardless of kinship.
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| 3. |
- Lindström, Åke, et al.
(författare)
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High basal metabolic rates of shorebirds while in the arctic: A circumpolar view
- 2003
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Ingår i: The Condor: ornithological applications. - 0010-5422. ; 105:3, s. 420-427
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Tidskriftsartikel (refereegranskat)abstract
- The basal metabolic rate (BMR) of Old World long-distance-migrant shorebirds has been found to vary along their migration route. On average, BMR is highest in the Arctic at the start of fall migration, intermediate at temperate latitudes, and lowest on the tropical wintering grounds. As a test of the generality of this pattern, we measured the BMR of one adult and 44 juvenile shorebirds of 10 species (1-18 individuals of each species, body-mass range 19-94 g) during the first part of their southward migration in the Canadian Arctic (68-76degreesN). The interspecific relationship between BMR and body mass was almost identical to that found for juvenile shorebirds in the Eurasian Arctic (5 species), although only one species appeared in both data sets. We conclude that high BMR of shorebirds in the Arctic is a circumpolar phenomenon. The most likely explanation is that the high BMR reflects physiological adaptations to low ambient temperatures. Whether the BMR of New World shorebirds drops during southward migration remains to be investigated.
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| 4. |
- Hou, Lianhai, et al.
(författare)
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A middle Eocene shorebird from China
- 2002
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Ingår i: The Condor. - 0010-5422 .- 1938-5129. ; 104, s. 896-899
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Tidskriftsartikel (refereegranskat)abstract
- We describe a new species of shorebird, tentatively referred to the family Charadriidae, from the Huadian Formation (Middle Eocene) in Jilin Province, China. In general morphology the specimen closely matches that of an extant charadriid, and correspondsin size to the Killdeer (Charadrius vociferus). If correctly identified this is the oldest record of the Charadriidae. The Middle Eocene paleoenvironment of the Huadian region is thought to have resembled a subtropical swamp.
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