The suspension of moult by trans-Saharan migrants in Crete

Swann, Robert L.; Baillie, Stephen R.

doi:10.1080/00063657909476617

Cited by 33 publications

(38 citation statements)

References 5 publications

(3 reference statements)

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“…There is a general trend for moult to be more likely to occur after autumn migration in the winter quarters as migration distance increases (Svensson & Hedenströ m 1999;Hall & Tullberg 2004). Populations breeding at northerly latitudes, with increased time stress, tend to interrupt postbreeding moult more often than southern conspecifics (Swann & Baillie 1979;Hedenström et al 1995). Similarly, late breeders among American redstarts Setophaga ruticilla initiate southbound migration but stop for moult during migration (Norris et al 2004).…”

Section: Moultmentioning

confidence: 99%

Adaptations to migration in birds: behavioural strategies, morphology and scaling effects

Hedenström

2007

Phil. Trans. R. Soc. B

243

217

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The annual life cycle of many birds includes breeding, moult and migration. All these processes are time and energy consuming and the extent of investment in any one may compromise the others. The output from breeding is of course the ultimate goal for all birds, while the investment in moult and migration should be selected so that lifetime fitness is maximized. In particular, long-distance migrants breeding at high latitudes face severe time pressures, which is a probable reason why natural selection has evolved efficient behaviours, physiological and morphological adaptations allowing the maximum possible migration speed. Optimal migration theory commonly assumes time minimization as an overall strategy, but the minimization of energy cost and predation risk may also be involved. Based on these assumptions, it is possible to derive adaptive behaviours such as when and at which fuel load a stopover site should be abandoned. I review some core components of optimal migration theory together with some key predictions. A review of accumulated empirical tests of the departure rule indicates that time minimization is an important component of the overall migration strategy, and hence gives support to the assumption about time-selected migration. I also briefly discuss how the optimal policy may be implemented by the bird by applying a set of simple rules. The time constraints on migrants increase with increasing body size. Some consequences of this are discussed.

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Section: Moultmentioning

confidence: 99%

Adaptations to migration in birds: behavioural strategies, morphology and scaling effects

Hedenström

2007

Phil. Trans. R. Soc. B

243

217

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“…Above all, it has been detected and studied in about 30 European trans-Saharan migrants and in some American migrants including Zonotrichia capensis hypoleuca, possibly the only altitudinal migrant (Murton 1968, Williamson 1968, Pimm 1970, King 1972, Payne 1972, Svensson 1975, Mead & Watmough 1976, Swann & Baillie 1979. More examples of European long-distance migrants will most certainly be found (s. Kasparek 1979Kasparek , 1981 dences, which will be treated in the following section.…”

Section: Introductionmentioning

confidence: 99%

“…According to Stresemann (1967) Mead & Watmough (1976) established three categories of interspecific variation, related to the proportion of individuals suspending their moult and the major tracts affected: (1) species in which most individuals migrate with suspended primary moult , (2) species usually completing moult before migration, but a variable proportion migrating with some old feathers (usually secondaries) retained, and (3) species usually moulting after migration, but a few individuals migrating with some new feathers (usually secondaries). Intraspecific geographical differences have been shown by Swann & Baillie (1979 According to Mead & Watmough (1976) the high variation in the moult course and its suspension especially in Muscicapa striata "suggests that there are adaptive pressures currently* affecting the moult". On the other hand, the same authors conclude from a short-term experiment undertaken by Lofts et al (1967) in all those cases in which the time to insert the moult between breeding and migration is so short that moult could not be completed it could be started and then on an individual basis facultatively interrupted whenever external circumstances related to migration require.…”

Section: Introductionmentioning

confidence: 99%

“…Suspended moult (e. g. Williamson 1968, King 1972, Mead & Watmough 1976, Swann & Baillie 1979, or "interrupted moult", Payne 1972, in earlier papers occasionally called "arrested moult", Murton 1968, Pimm 1973 pause", Stresemann & Stresemann l. c.) means moult of wing and tail feathers with a "temporary int erruption of feather replacement" (King 1972) in which normally part of the feathers is moulted before departure from the breeding grounds and the rest after the migratory period or before and after a breeding period, respectively.…”

Section: Introductionmentioning

confidence: 99%

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On the Control of Suspended Moult in an European Trans-Saharan Migrant, the Orphean Warbler

Berthold

Querner

1982

Journal of the Yamashina Institute for Ornithology

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Suspended moult is a special adaptive moult strategy which is widespread in longdistance migrants. The replacement of remiges and rectrices in this type of moult starts before migration but then is interrupted during migration. So far, it has virtually not been investigated experimentally.We carried out an investigation on the Orphean Warbler, Sylvia hortensis, an European trans-Saharan migrant known commonly to suspend its moult. We studied 15 trapped adults and 8 handraised young individuals, which were kept in light conditions simulating those to which freeliving conspecifics are normally exposed in the course of a year. In the first experimental year, the adults, caught during breeding, all suspended their moult and retained some old primaries, secondaries, and tertials. In the second experimental year, when the same birds were prevented from breeding, they moulted weeks earlier, and, as a result, completed their moult before the migratory period. Similarly, the handraised birds showed a complete moult in their second year. Thus, the suspended moult of the Orphean Warbler is not based on strictly endogenously controlled moult programs with preprogrammed moult pauses. Moult in this species can be adapted on a facultative basis to various conditions experienced. The course of the moult and its suspension appear to be linked to the preceeding individual breeding season, and some conceivable control mechanisms are discussed in detail.

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“…In some cases, the timing of moult is intermediate, such as in the barred warbler, Sylvia nisoria, where the flight feather moult is split between summer and winter grounds (Hasselquist et al 1988;Lindström et al 1993a). In addition, depending on the population, the degree of moult suspension may vary a great deal (Swann & Baillie 1979;Hedenström et al 1995). There is hence some correlation between migration distance and the timing and location of moult (Svensson & Hedenströ m 1999).…”

Section: Introductionmentioning

confidence: 99%

Optimal moult strategies in migratory birds

Barta

McNamara

Houston

et al. 2007

Phil. Trans. R. Soc. B

146

187

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Avian migration, which involves billions of birds flying vast distances, is known to influence all aspects of avian life. Here we investigate how birds fit moult into an annual cycle determined by the need to migrate. Large variation exists in moulting patterns in relation to migration: for instance, moult can occur after breeding in the summer or after arrival in the wintering quarters. Here we use an optimal annual routine model to investigate why this variation exists. The modelled bird's decisions depend on the time of year, its energy reserves, breeding status, experience, flight feather quality and location. Our results suggest that the temporal and spatial variations in food are an important influence on a migratory bird's annual cycle. Summer moult occurs when food has a high peak on the breeding site in the summer, but it is less seasonal elsewhere. Winter moult occurs if there is a short period of high food availability in summer and a strong winter peak at different locations (i.e. the food is very seasonal but in opposite phase on these areas). This finding might explain why only long-distance migrants have a winter moult.

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The suspension of moult by trans-Saharan migrants in Crete

Cited by 33 publications

References 5 publications

Adaptations to migration in birds: behavioural strategies, morphology and scaling effects

Adaptations to migration in birds: behavioural strategies, morphology and scaling effects

On the Control of Suspended Moult in an European Trans-Saharan Migrant, the Orphean Warbler

Optimal moult strategies in migratory birds

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