Plumage quality mediates a life-history trade-off in a migratory bird

Patrycja Podlaszczuk,Krzysztof Kaczmarek,Piotr Minias,Maciej Kamiński,Radosław Włodarczyk,Tomasz Janiszewski

doi:10.1186/s12983-016-0179-4

Patrycja Podlaszczuk, Krzysztof Kaczmarek + Show 4 more

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https://doi.org/10.1186/s12983-016-0179-4

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Abstract

BackgroundMoult is one of the most costly activities in the annual cycle of birds and most avian species separate moult from other energy-demanding activities, such as migration. To this end, young birds tend to undergo the first post-juvenile moult before the onset of migration, but in some species the time window for the pre-migratory feather replacement is too narrow. We hypothesized that in such species an increased investment in the structural quality of juvenile feathers may allow to retain juvenile plumage throughout the entire migratory period and delay moult until arriving at wintering grounds, thus avoiding a moult-migration overlap.MethodsThe effect of juvenile plumage quality on the occurrence of moult-migration overlap was studied in a migratory shorebird, the common snipe Gallinago gallinago. Ca. 400 of first-year common snipe were captured during their final stage of autumn migration through Central Europe. The quality of juvenile feathers was assessed as the mass-length residuals of retained juvenile rectrices. Condition of migrating birds was assessed with the mass of accumulated fat reserves and whole-blood hemoglobin concentration. Path analysis was used to disentangle complex interrelationships between plumage quality, moult and body condition.ResultsSnipe which grew higher-quality feathers in the pre-fledging period were less likely to initiate moult during migration. Individuals moulting during migration had lower fat loads and hemoglobin concentrations compared to non-moulting birds, suggesting a trade-off in resource allocation, where energetic costs of moult reduced both energy reserves available for migration and resources available for maintenance of high oxygen capacity of blood.ConclusionsThe results of this study indicate that a major life-history trade-off in a migratory bird may be mediated by the quality of juvenile plumage. This is consistent with a silver spoon effect, where early-life investment in feather quality affects future performance of birds during migration period. Our results strongly suggest that the juvenile plumage, although retained for a relatively short period of time, may have profound consequences for individuals’ fitness.Electronic supplementary materialThe online version of this article (doi:10.1186/s12983-016-0179-4) contains supplementary material, which is available to authorized users.

Highlights

Moult is one of the most costly activities in the annual cycle of birds and most avian species separate moult from other energy-demanding activities, such as migration
Juvenile feathers are simpler in structure and generally weaker than later generations, as chicks usually face a trade-off between investment in feather quality and rapid body growth [9]
The common snipe breeds in Poland and neighbouring Central European countries, we have no evidence that local individuals use Jeziorsko reservoir as a fuelling site prior to autumn migration and ringing recoveries indicate that long-distance migrants from Central Russia are mostly captured at this site [20]

Summary

Introduction

Moult is one of the most costly activities in the annual cycle of birds and most avian species separate moult from other energy-demanding activities, such as migration. To this end, young birds tend to undergo the first post-juvenile moult before the onset of migration, but in some species the time window for the pre-migratory feather replacement is too narrow. While there is abundant empirical evidence for silver spoon effects mediated by nestling condition [4,5,6], information on how an investment in the quality of the first post-natal (juvenile) plumage affects future performance in birds is almost lacking [7]. High-quality juvenile feathers should be more wear-resistant [12], which means that birds could retain them longer before they need to be replaced with a next-generation plumage during the post-juvenile moult

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