Flight muscle hypertrophy and ecophysiological variation of Yellow wagtail Motacilla flava races at Lake Chad
Article first published online: 20 AUG 2009
Journal of Zoology
Volume 167, Issue 3, pages 293–306, July 1972
How to Cite
Fry, C. H., Ferguson-Lees, I. J. and Dowsett, R. J. (1972), Flight muscle hypertrophy and ecophysiological variation of Yellow wagtail Motacilla flava races at Lake Chad. Journal of Zoology, 167: 293–306. doi: 10.1111/j.1469-7998.1972.tb03113.x
- Issue published online: 20 AUG 2009
- Article first published online: 20 AUG 2009
- Accepted 14 December 1971
During the few days before emigration to the Palaearctic, the weight of Yellow wagtails wintering in Africa doubles. Most of the increase is due to the deposition of fat, as is well known, but a part of it is shown to result from hypertrophy of the pectoral muscles. The same applies to other Palaearctic birds, four warblers and a hirundine, that winter in Africa.
Eleven subspecies of M. flava occur at Lake Chad in spring. The four black-headed ones have more restricted habitat requirements than some of the others; however, no differences in diet have been found. There is no evidence of hyperphagia and little of diet change when fattening. Broadly, the races that have farthest to migrate leave earliest, and their sexual recrudescence and fattening are early.
Yellow wagtails wintering at or passing through Lake Chad breed mainly in eastern Europe (from the Adriatic to the Gulf of Finland, between about 12° and 30°E). They probably migrate on a great circle route, and during the flight lose one gram of weight, mainly fat, per 200 km.