Energy of flight in Swallows and Swifts

Report on

Lyuleeva, D.S. (1970): Energy of flight in Swallows and Swifts (Russian). Doklady Akademii Nauk SSSR, Series biol. 190, No 6, p. 1467-1469

Люлеева, Д. С. (1970): Энергия полета у ласточек и стрижей

(APUSlist No. 0422)

by IGOR FEFELOV

Experiments on the mass loss in flight were carried out on ten adult nesting Barn Swallows (Hirundo rustica), eight House Martins (Delichon urbica), and five Common Swifts (Apus apus) in 1961. First, breeding birds were caught in colonies or nests and ringed. Later they were captured, kept in darkness for several hours, and then were moved to distances of 1, 40, or 70 km southwards from their nestsite and released to test their nesting fidelity.

After the fidelity was proven the second experiment was executed. The birds were weighed and again brought to the same distant locations where they were released. Their bills were closed with a thread so that they could not take food during their return flight to the nests. Immediately after the return, they were recaptured and weighed.

The body mass of Swifts was from 39.15 to 42.55 gr before the experiment and 31.22 to 37.97 gr after it. The mass loss was from 2.15 to 4.58 gr in four birds that returned quickly; one individual that returned after 20 hours had lost 8.43 gr. The Swifts lost from 0.216 to 0.498 gr per hour in flight (an average 0.318 gr per hour), which is equal to 0.007 gr per hour for 1 gr of their own weight. Thus it was found that the flight of the Swift is almost twice as energy-efficient as that of the Swallow or the House Martin.