How Wing Shape and Weather Affect Songbird Migration Costs
Author Information
Author(s): Melissa S. Bowlin, Martin Wikelski
Primary Institution: Princeton University
Hypothesis
Pointed wings and low wingloading reduce energy consumption during migratory flight in songbirds.
Conclusion
Pointed wingtips and low wingloading help small birds save energy during migration, and high winds and atmospheric instability increase their energy use.
Supporting Evidence
- Birds with more pointed wingtips had lower heart rates during flight.
- Higher wind speeds were associated with increased heart rates.
- The study provides the first direct test of the relationship between morphology and energy expenditure in migrating songbirds.
Takeaway
Birds with pointy wings use less energy when flying, and strong winds make them work harder. This means that climate change could make migration tougher for them.
Methodology
The study measured heart rates of 15 Swainson's Thrushes during migratory flights using radio transmitters to assess energy expenditure.
Limitations
The study could not obtain exact altitudes for the birds, which limited the accuracy of atmospheric condition estimates.
Participant Demographics
Swainson's Thrushes (Catharus ustulatus), small passerine birds weighing 25-35 g.
Statistical Information
P-Value
p=0.009 for wingtip pointedness, p=0.008 for wingloading
Statistical Significance
p<0.001
Digital Object Identifier (DOI)
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