Wind-assisted sprint migration in northern swifts

Area of Science:

• Ornithology
• Animal Migration
• Bioenergetics

Background:

• Long-distance animal migration is a widespread phenomenon.
• Avian migration speed depends on fueling, flight efficiency, and wind conditions.
• Small birds like swifts are predicted to achieve high speeds using fly-and-forage strategies.

Purpose of the Study:

• To investigate seasonal migration strategies and speeds of common swifts.
• To analyze Global Location Sensing (GLS) tracking data from European common swifts.
• To compare observed migration speeds with existing theoretical predictions.

Main Methods:

• Utilized GLS tracking data from common swifts.
• Calculated overall migration speeds (km/day).
• Analyzed seasonal differences in wind support along migration routes.

Main Results:

• Common swifts exhibited average migration speeds of 570 km/day, with a maximum of 832 km/day over 9 days.
• Observed speeds significantly exceeded previous predictions for swifts.
• Spring migration routes offered 20% more tailwind support than autumn routes.

Conclusions:

• Common swifts achieve exceptional migration speeds through a combination of strategies.
• High fueling rates at stopovers and foraging during flight are crucial.
• Strategic use of tailwinds, particularly in spring, enhances migration efficiency.