Food availability affects migratory restlessness in caged garden warblers (Sylvia borin)

1985 ◽  
Vol 72 (1) ◽  
pp. 51-52 ◽  
Author(s):  
E. Gwinner ◽  
H. Biebach ◽  
I. v. Kries
Keyword(s):  
Food Availability ◽  
Migratory Restlessness ◽  
Sylvia Borin

Time-place learning, food availability and the exploitation of patches in garden warblers, Sylvia borin

1994 ◽  
Vol 48 (2) ◽  
pp. 273-284 ◽  
Author(s):  
Herbert Biebach ◽  
John R. Krebs ◽  
Helene Falk
Keyword(s):  
Food Availability ◽  
Place Learning ◽  
Sylvia Borin

scholarly journals Ghrelin affects stopover decisions and food intake in a long-distance migrant

2017 ◽  
Vol 114 (8) ◽  
pp. 1946-1951 ◽  
Author(s):  
Wolfgang Goymann ◽  
Sara Lupi ◽  
Hiroyuki Kaiya ◽  
Massimiliano Cardinale ◽  
Leonida Fusani
Keyword(s):  
Food Intake ◽  
Peptide Hormone ◽  
Migratory Behavior ◽  
Migratory Restlessness ◽  
Long Distance ◽  
Stopover Site ◽  
Blood Concentrations ◽  
Timing Of Migration ◽  
Fat Stores ◽  
Sylvia Borin

Billions of birds migrate long distances to either reach breeding areas or to spend the winter at more benign places. On migration, most passerines frequently stop over to rest and replenish their fuel reserves. To date, we know little regarding how they decide that they are ready to continue their journey. What physiological signals tell a bird’s brain that its fuel reserves are sufficient to resume migration? A network of hormones regulates food intake and body mass in vertebrates, including the recently discovered peptide hormone, ghrelin. Here, we show that ghrelin reflects body condition and influences migratory behavior of wild birds. We measured ghrelin levels of wild garden warblers (Sylvia borin) captured at a stopover site. Further, we manipulated blood concentrations of ghrelin to test its effects on food intake and migratory restlessness. We found that acylated ghrelin concentrations of garden warblers with larger fat scores were higher than those of birds without fat stores. Further, injections of unacylated ghrelin decreased food intake and increased migratory restlessness. These results represent experimental evidence that appetite-regulating hormones control migratory behavior. Our study lays a milestone in migration physiology because it provides the missing link between ecologically dependent factors such as condition and timing of migration. In addition, it offers insights in the regulation of the hormonal system controlling food intake and energy stores in vertebrates, whose disruption causes eating disorders and obesity.

scholarly journals The amount of available food affects diurnal locomotor activity in migratory songbirds during stopover

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Andrea Ferretti ◽  
Ivan Maggini ◽  
Sara Lupi ◽  
Massimiliano Cardinale ◽  
Leonida Fusani
Keyword(s):  
Locomotor Activity ◽  
Food Availability ◽  
Migratory Birds ◽  
Migratory Restlessness ◽  
Locomotory Activity ◽  
Central Mediterranean ◽  
Stopover Site ◽  
Stopover Sites ◽  
Migrating Birds ◽  
Spring Stopover

AbstractMigratory passerine birds fly long distances twice a year alternating nocturnal flights with stopovers to rest and replenish energy stores. The duration of each stopover depends on several factors including internal clocks, meteorological conditions, and environmental factors such as availability of food. Foraging entails energetic costs, and if birds need to refuel efficiently, they should modulate their activity in relation to food availability. We investigated how food availability influences locomotor activity in migrating birds of six passerine species at a spring stopover site in the central Mediterranean Sea. We selected birds with low fat scores which we expected to be strongly motivated to refuel. We simulated stopover sites of different quality by providing temporarily caged birds with different amounts of food to simulate scarce to abundant food. We analysed the diurnal locomotory activity as a proxy for food searching effort. Low food availability resulted in an increased diurnal locomotor activity in almost all species, while all birds showed low intensity of nocturnal migratory restlessness. In conclusion, our study shows that food availability in an important determinant of behaviour of migratory birds at stopover sites.

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