Aspects of the Molt Migration

Jehl, Joseph R.

doi:10.1007/978-3-642-74542-3_7

Cited by 37 publications

(30 citation statements)

References 12 publications

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“…Another variant is the moult migration of waterfowl, in which birds travel after breeding to special areas, offering security and food, where they moult all their flight feathers simultaneously (becoming temporarily flightless), before moving on to wintering areas (Salomonsen 1968;Jehl 1990). Moult migration adds another component to the annual cycle.…”

Section: The Moult Migration Of Waterfowlmentioning

confidence: 99%

Migration within the annual cycle: species, sex and age differences

Newton

2011

J Ornithol

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International audienceThe three main energy-demanding events in the yearly cycles of birds--breeding, moult and migration--tend to occur at different times of year from one another, with minimal overlap. The sequence in which these various events occur varies according to the ecological conditions (including those encountered during migration) in which particular populations live, and in general, moult is more variable in timing than other events. Some migratory birds moult in their breeding areas after nesting is over, others moult at a staging area on migration, while others moult in winter quarters. Yet others show a split moult, replacing part of their plumage in one place and part in another, moult usually being arrested during the intervening migration. Split moults are often associated with split migrations, as the birds pause for several weeks on their journeys to replace their feathers. Different variants in these patterns occur in different geographical populations of the same species. Some types of birds overlap breeding and moult, and some also overlap moult and migration, especially body moult, which can occur without reducing flight efficiency. A few bird species, with short breeding cycles, have been found to nest in two different areas in a single year, separated by migration. In species in which the young are raised by only one parent, the other parent is able to begin post-breeding moult or migration at a much earlier date. In species in which individuals do not breed in their early years of life, moults and migrations are shifted into the more favourable period which in older birds is occupied by breeding. The main message of this review is the huge variation that occurs in the annual cycles of birds, in the timing and duration of different processes, the sequence in which they occur, and the degree of overlap between them. Variations occur not only between species and populations but also between sex and age-groups within the same population. It is suggested that many species remain in a state of suspended readiness for breeding, moult or migration, and can undertake any of these processes over a greater part of the year than that in which they are normally expressed. Two or more of these processes can remain in this state of readiness simultaneously, enabling the bird to suppress, advance or delay a particular process, according to the conditions in which it finds itself

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Section: The Moult Migration Of Waterfowlmentioning

confidence: 99%

Migration within the annual cycle: species, sex and age differences

Newton

2011

J Ornithol

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“…Indeed, moult rarely overlaps with breeding or with the cruellest months of the winter (Payne 1972;Masman et al 1988;Dietz et al 1992). Furthermore, migration and moult rarely overlap (Payne 1972) and in some taxa, such as waterfowl and grebes, moult completely constrains migration as it prevents the birds from flying (see Jehl (1990) for a review). However, in other taxa flying remains possible but moult imparts an energetic cost, limiting overlap with migration.…”

Section: Introduction: Annual Cycles and Life-history Trade-offs In Amentioning

confidence: 99%

Travelling on a budget: predictions and ecological evidence for bottlenecks in the annual cycle of long-distance migrants

Buehler

Piersma

2007

Phil. Trans. R. Soc. B

204

228

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Long-distance migration, and the study of the migrants who undertake these journeys, has fascinated generations of biologists. However, many aspects of the annual cycles of these migrants remain a mystery as do many of the driving forces behind the evolution and maintenance of the migrations themselves. In this article we discuss nutritional, energetic, temporal and disease-risk bottlenecks in the annual cycle of long-distance migrants, taking a sandpiper, the red knot Calidris canutus, as a focal species. Red knots have six recognized subspecies each with different migratory routes, well-known patterns of connectivity and contrasting annual cycles. The diversity of red knot annual cycles allows us to discuss the existence and the effects of bottlenecks in a comparative framework. We examine the evidence for bottlenecks focusing on the quality of breeding plumage and the timing of moult as indicators in the six subspecies. In terms of breeding plumage coloration, quality and timing of prealternate body moult (from non-breeding into breeding plumage), the longest migrating knot subspecies, Calidris canutus rogersi and Calidris canutus rufa, show the greatest impact of bottlenecking. The same is true in terms of prebasic body moult (from breeding into non-breeding plumage) which in case of both C. c. rogersi and C. c. rufa overlaps with southward migration and may even commence in the breeding grounds. To close our discussion of bottlenecks in long-distance migrants, we make predictions about how migrants might be impacted via physiological 'trade-offs' throughout the annual cycle, using investment in immune function as an example. We also predict how bottlenecks may affect the distribution of mortality throughout the annual cycle. We hope that this framework will be applicable to other species and types of migrants, thus expanding the comparative database for the future evaluation of seasonal selection pressures and the evolution of annual cycles in long-distance migrants. Furthermore, we hope that this synthesis of recent advancements in the knowledge of red knot annual cycles will prove useful in the ongoing attempts to model annual cycles in migratory birds.

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“…Because birds become flightless, they may be more vulnerable to changes in food resources, weather, or predation. Increased nutrient demands or predator avoidance (Panek and Majewski 1990;Guillemette et al 2007) may drive some species to specific locations to molt ("molt migration" ;Jehl 1990;Peterson et al 2006). Such strategies are deployed by many species that undergo simultaneous molt (Little and Furness 1985;Storer and Jehl 1985;Petersen et al 2006).…”

Section: Western Grebes (Aechmophorus Occidentalis)mentioning

confidence: 98%