| 73181. |
- Klaassen, Marcel, et al.
(författare)
-
Departure fuel loads in time-minimizing migrating birds can be explained by the energy costs of being heavy
- 1996
-
Ingår i: Journal of Theoretical Biology. - : Elsevier BV. - 1095-8541 .- 0022-5193. ; 183:1, s. 29-34
-
Tidskriftsartikel (refereegranskat)abstract
- Lindström & Alerstam (1992Am. Nat.140,477–491) presented a model that predicts optimal departure fuel loads as a function of the rate of fuel deposition in time-minimizing migrants. The basis of the model is that the coverable distance per unit of fuel deposited, diminishes with increasing fuel load. This is an effect of the increasing flight costs associated with increasing body mass. Lindström & Alerstam (1992) found that birds left at lower fuel loads than their model predicted for which they considered various ecological explanations. Alternatively, we hypothesize that the difference between prediction and empirical data might be a result of extra resting metabolic and transport costs associated with an increase in fuel load during stopover. We develop a new version of the Lindström & Alerstam (1992) model taking fuel load associated costs during stopover into account. We fit empirical data from rufous hummingbirdsSelasphorus rufus(Carpenteret al., 1983Proc. Natl. Acad. Sci. U.S.A.80,7259–7263) and bluethroatsLuscinia svecica(Lindström & Alerstam, 1992) to this new model. Estimated fuel-load costs are discussed in relation to knowledge presently available on variations in basal metabolic costs and transport costs with body mass. We show that fuel-load costs within a reasonable range can explain the observed departure fuel loads when migrating birds are time minimizers.
|
|
| 73182. |
- Klaassen, M, et al.
(författare)
-
Flight costs and fuel composition of a bird migrating in a wind tunnel
- 2000
-
Ingår i: The Condor: ornithological applications. - 0010-5422. ; 102:2, s. 444-451
-
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.
|
|
| 73183. |
|
|
| 73184. |
- Klaassen, M, et al.
(författare)
-
Metabolic rate and thermal conductance of lemmings from high-arctic Canada and Siberia
- 2002
-
Ingår i: Journal of Comparative Physiology B. - : Springer Science and Business Media LLC. - 0174-1578. ; 172:5, s. 371-378
-
Tidskriftsartikel (refereegranskat)abstract
- The arctic climate places high demands on the energy metabolism of its inhabitants. We measured resting (RMR) and basal metabolic rates (BMR), body temperatures, and dry and wet thermal conductances in summer morphs of the lemmings Dicrostonyx groenlandicus and Lemmus trimucronatus in arctic Canada, and the BMR of D. torquatus, D. groenlandicus, L. sibiricus, L. bungei and L. trimucronatus in Siberia. In contrast to previous studies the data were collected on animals that had spent only a limited time in captivity. All parameters were analysed in relation to the variations in body mass (20-90 g). Body temperature and BMR were lower in D. groenlandicus than L. trimucronatus, which coincides with greater longevity in the former species. Wet and dry thermal conductances of both species were similar and comparable with those of other Myomorpha (mouse-type rodents), indicating no evidence for a previously claimed lower thermal conductance in lemmings. BMR in lemmings appeared to be higher than in other Arvicolidae (voles, lemmings and muskrats), which could relate to their typically high-latitude distribution. However, the more southerly living Lemmus species had higher BMR than the more northerly living Dicrostonyx species, which may be explained by the former having a relatively low-quality diet.
|
|
| 73185. |
|
|
| 73186. |
- Klaassen, Raymond, et al.
(författare)
-
Flexibility in daily travel routines causes regional variation in bird migration speed
- 2008
-
Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 1432-0762 .- 0340-5443. ; 62:9, s. 1427-1432
-
Tidskriftsartikel (refereegranskat)abstract
- We used novel Global Positioning System-based satellite telemetry to reconstruct daily time budgets on travelling days of a long-distance migrant, the Osprey Pandion haliaetus, to reveal how landscape affects migratory performance. We compared daily travel routines between the Ospreys' passage of Europe and the Sahara. In Europe, where feeding habitat is abundant, Ospreys fed both before-after flights and during interruptions, thus, combining migration with foraging. This resulted in a 2.7-h shorter daily flight period in Europe than in the Sahara. A calculated energy budget indicated that a 'fly-and-forage migration strategy' is favourable in Europe because associated benefits (energy intake) more than outweigh costs (reduced flight time). The much shorter flight time in Europe was the main explanation why Ospreys covered on average 78 km less distance on a travelling day in Europe than in the Sahara. In addition, there were regional differences in hourly flight speeds that are most probably the result of variation in thermal soaring conditions. We conclude that landscape properties have a profound effect on migration through regional variation in daily routines.
|
|
| 73187. |
- Klaassen, Raymond, et al.
(författare)
-
Geographical and temporal flexibility in the response to crosswinds by migrating raptors.
- 2011
-
Ingår i: Proceedings of the Royal Society B: Biological Sciences. - : The Royal Society. - 1471-2954 .- 0962-8452. ; 278, s. 1339-1346
-
Tidskriftsartikel (refereegranskat)abstract
- Wind and ocean currents may potentially have important effects on travelling animals, as an animal which does not respond to lateral flow will be drifted from its intended direction of movement. By analysing daily movements of migrating ospreys Pandion haliaetus and marsh harriers Circus aeruginosus, as recorded by satellite telemetry, in relation to global wind data, we showed that these raptors allow on average 47 per cent drift. Furthermore, our analyses revealed significant geographical and temporal variation in the response to crosswinds. During some parts of the migration, the birds drifted and in other parts they compensated or even overcompensated. In some regions, the response of marsh harriers depended on the wind direction. They drifted when the wind came from one side and (over)compensated when the wind came from the opposite side, and this flexible response was different in different geographical regions. These results suggest that migrating raptors modulate their response to crosswinds at different places and times during their travels and show that individual birds use a much more varied repertoire of behavioural responses to wind than hitherto assumed. Our results may also explain why contrasting and variable results have been obtained in previous studies of the effect of wind on bird migration.
|
|
| 73188. |
- Klaassen, Raymond, et al.
(författare)
-
Great flights by great snipes: long and fast non-stop migration over benign habitats.
- 2011
-
Ingår i: Biology letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 7, s. 833-835
-
Tidskriftsartikel (refereegranskat)abstract
- Migratory land birds perform extreme endurance flights when crossing ecological barriers, such as deserts, oceans and ice-caps. When travelling over benign areas, birds are expected to migrate by shorter flight steps, since carrying the heavy fuel loads needed for long non-stop flights comes at considerable cost. Here, we show that great snipes Gallinago media made long and fast non-stop flights (4300-6800 km in 48-96 h), not only over deserts and seas but also over wide areas of suitable habitats, which represents a previously unknown migration strategy among land birds. Furthermore, the great snipes achieved very high ground speeds (15-27 m s(-1)), which was not an effect of strong tailwind support, and we know of no other animal that travels this rapidly over such a long distance. Our results demonstrate that some migratory birds are prepared to accept extreme costs of strenuous exercise and large fuel loads, even when stopover sites are available along the route and there is little tailwind assistance. A strategy of storing a lot of energy before departure, even if migration is over benign habitats, may be advantageous owing to differential conditions of fuel deposition, predation or infection risk along the migration route.
|
|
| 73189. |
- Klaassen, Raymond, et al.
(författare)
-
Loop migration in adult marsh harriers Circus aeruginosus, as revealed by satellite telemetry
- 2010
-
Ingår i: Journal of Avian Biology. - 0908-8857 .- 1600-048X. ; 41:2, s. 200-207
-
Tidskriftsartikel (refereegranskat)abstract
- Loop migration among birds is characterized by the spring route lying consistently west or east of the autumn route. The existence of loops has been explained by general wind conditions or seasonal differences in habitat distribution. Loop migration has predominantly been studied at the population level, for example by analysing ring recoveries. Here we study loop migration of individual marsh harriers Circus aeruginosus tracked by satellite telemetry. We show that despite a generally narrow migration corridor the harriers travelled in a distinct clockwise loop through Africa and southern Europe, following more westerly routes in spring than in autumn. We used the Normalized Difference Vegetation Index (NDVI) to identify potential feeding habitat in Africa. Suitable habitat seemed always more abundant along the western route, both in spring and autumn, and no important stopover site was found along the eastern route. Observed routes did thus not coincide with seasonal variation in habitat availability. However, favourable habitat might be more important during spring migration, when the crossing of the Sahara seems more challenging, and thus habitat availability might play an indirect role in the harriers' route choice. Grid-based wind data were used to reconstruct general wind patterns, and in qualitative agreement with the observed loop marsh harriers predominantly encountered westerly winds in Europe and easterly winds in Africa, both in autumn and in spring. By correlating tail- and crosswinds with forward and perpendicular movement rates, respectively, we show that marsh harriers are partially drifted by wind. Thus, we tentatively conclude that wind rather than habitat seems to have an overriding effect on the shape of the migration routes of marsh harriers. General wind conditions seem to play an important role also in the evolution of narrow migratory loops as demonstrated for individual marsh harriers.
|
|
| 73190. |
- Klaassen, Raymond, et al.
(författare)
-
Migration strategy of a flight generalist, the Lesser Black-backed Gull Larus fuscus
- 2012
-
Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 23:1, s. 58-68
-
Tidskriftsartikel (refereegranskat)abstract
- Migrating birds are believed to minimize the time spent on migration rather than energy. Birds seem to maximize migration speed in different ways as a noteworthy variation in migration strategies exists. We studied migration strategies of a flight mode and feeding generalist, the Lesser Black-backed Gull Larus fuscus, using GPS-based satellite telemetry. We expected the gulls to achieve very high overall migration speeds by traveling via the shortest direct route, traveling during a large part of the day and night, and making few and short stopovers. Fourteen individuals were tracked between the Dutch breeding colony and the wintering sites in England, southern Europe and northwest Africa. The gulls did not travel via the shortest possible route but made substantial detours by their tendency to follow coasts. Although the gulls traveled during most of the day, and sometimes during the night, they did not achieve long daily distances (177 and 176 km/day in autumn and spring, respectively), which is explained by the gulls stopping frequently on travel days to forage. Furthermore, due to frequent and long migratory stopovers, their overall migration speed was among the lowest recorded for migratory birds (44 and 98 km/day, in autumn and spring, respectively). A possible explanation for the unexpected frequent stopovers and low migration speeds is that gulls do not minimize the duration of migration but rather minimize the costs of migration. Energy rather than time might be important for short-distance migrating birds, resulting in very different migration strategies compared with long-distance migrants.
|
|
