Limits...
The cost of migration: spoonbills suffer higher mortality during trans-Saharan spring migrations only.

Lok T, Overdijk O, Piersma T - Biol. Lett. (2015)

Bottom Line: Although in some studies, the relationships between migration distance and breeding success or annual survival are established, none has investigated whether mortality during the actual migration increases with migration distance.Here, we compared seasonal survival between Eurasian spoonbills (Platalea leucorodia leucorodia) that breed in The Netherlands and migrate different distances (ca 1000, 2000 and 4500 km) to winter in France, Iberia and Mauritania, respectively.On the basis of resightings of individually marked birds throughout the year between 2005 and 2012, we show that summer, autumn and winter survival were very high and independent of migration distance, whereas mortality during spring migration was much higher (18%) for the birds that wintered in Mauritania, compared with those flying only as far as France (5%) or Iberia (6%).

View Article: PubMed Central - PubMed

Affiliation: Chair in Global Flyway Ecology, Animal Ecology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, PO Box 11103, 9700 CC Groningen, The Netherlands Department of Marine Ecology, NIOZ Royal Netherlands Institute for Sea Research, PO Box 59, 1790 AB Den Burg, Texel, The Netherlands tamarlok@gmail.com.

ABSTRACT
Explanations for the wide variety of seasonal migration patterns of animals all carry the assumption that migration is costly and that this cost increases with migration distance. Although in some studies, the relationships between migration distance and breeding success or annual survival are established, none has investigated whether mortality during the actual migration increases with migration distance. Here, we compared seasonal survival between Eurasian spoonbills (Platalea leucorodia leucorodia) that breed in The Netherlands and migrate different distances (ca 1000, 2000 and 4500 km) to winter in France, Iberia and Mauritania, respectively. On the basis of resightings of individually marked birds throughout the year between 2005 and 2012, we show that summer, autumn and winter survival were very high and independent of migration distance, whereas mortality during spring migration was much higher (18%) for the birds that wintered in Mauritania, compared with those flying only as far as France (5%) or Iberia (6%). As such, this study is the first to show empirical evidence for increased mortality during some long migrations, likely driven by the presence of a physical barrier (the Sahara desert) in combination with suboptimal fuelling and unfavourable weather conditions en route.

Show MeSH

Related in: MedlinePlus

Seasonal survival of birds wintering in France, Iberia and Mauritania.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4321157&req=5

RSBL20140944F2: Seasonal survival of birds wintering in France, Iberia and Mauritania.

Mentions: Survival differed between the seasons and was especially low during spring migration (table 1 and figure 2). There was also a strong effect of migration strategy on spring migration survival (the sum of Akaike weights of models including the effect (∑wi) = 1.00, table 1), with birds wintering in Mauritania being three times more likely to die during spring migration (17.7%) than birds wintering in France (5.1%) or Iberia (5.6%) (figure 2). This result was not explained by an incidental mass mortality of Mauritanian winterers during spring migration [18], as modelling annual variation revealed that the pattern was consistent in four of the six years. During the other three seasons, survival was very high and independent of migration strategy (∑wi = 0.41, 0.33 and 0.29 for the models including an effect of migration strategy on autumn, winter and summer survival, respectively; table 1 and figure 1).Table 1.


The cost of migration: spoonbills suffer higher mortality during trans-Saharan spring migrations only.

Lok T, Overdijk O, Piersma T - Biol. Lett. (2015)

Seasonal survival of birds wintering in France, Iberia and Mauritania.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4321157&req=5

RSBL20140944F2: Seasonal survival of birds wintering in France, Iberia and Mauritania.
Mentions: Survival differed between the seasons and was especially low during spring migration (table 1 and figure 2). There was also a strong effect of migration strategy on spring migration survival (the sum of Akaike weights of models including the effect (∑wi) = 1.00, table 1), with birds wintering in Mauritania being three times more likely to die during spring migration (17.7%) than birds wintering in France (5.1%) or Iberia (5.6%) (figure 2). This result was not explained by an incidental mass mortality of Mauritanian winterers during spring migration [18], as modelling annual variation revealed that the pattern was consistent in four of the six years. During the other three seasons, survival was very high and independent of migration strategy (∑wi = 0.41, 0.33 and 0.29 for the models including an effect of migration strategy on autumn, winter and summer survival, respectively; table 1 and figure 1).Table 1.

Bottom Line: Although in some studies, the relationships between migration distance and breeding success or annual survival are established, none has investigated whether mortality during the actual migration increases with migration distance.Here, we compared seasonal survival between Eurasian spoonbills (Platalea leucorodia leucorodia) that breed in The Netherlands and migrate different distances (ca 1000, 2000 and 4500 km) to winter in France, Iberia and Mauritania, respectively.On the basis of resightings of individually marked birds throughout the year between 2005 and 2012, we show that summer, autumn and winter survival were very high and independent of migration distance, whereas mortality during spring migration was much higher (18%) for the birds that wintered in Mauritania, compared with those flying only as far as France (5%) or Iberia (6%).

View Article: PubMed Central - PubMed

Affiliation: Chair in Global Flyway Ecology, Animal Ecology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, PO Box 11103, 9700 CC Groningen, The Netherlands Department of Marine Ecology, NIOZ Royal Netherlands Institute for Sea Research, PO Box 59, 1790 AB Den Burg, Texel, The Netherlands tamarlok@gmail.com.

ABSTRACT
Explanations for the wide variety of seasonal migration patterns of animals all carry the assumption that migration is costly and that this cost increases with migration distance. Although in some studies, the relationships between migration distance and breeding success or annual survival are established, none has investigated whether mortality during the actual migration increases with migration distance. Here, we compared seasonal survival between Eurasian spoonbills (Platalea leucorodia leucorodia) that breed in The Netherlands and migrate different distances (ca 1000, 2000 and 4500 km) to winter in France, Iberia and Mauritania, respectively. On the basis of resightings of individually marked birds throughout the year between 2005 and 2012, we show that summer, autumn and winter survival were very high and independent of migration distance, whereas mortality during spring migration was much higher (18%) for the birds that wintered in Mauritania, compared with those flying only as far as France (5%) or Iberia (6%). As such, this study is the first to show empirical evidence for increased mortality during some long migrations, likely driven by the presence of a physical barrier (the Sahara desert) in combination with suboptimal fuelling and unfavourable weather conditions en route.

Show MeSH
Related in: MedlinePlus