Figures are mean values. From Moreau & Dolp (1970).

Figures are mean values. From Moreau & Dolp (1970).

the types of journeys undertaken. Some studies have also examined the composition of different components of the body separately, such as the various muscles and digestive organs (see later).1

The bodies of resident bird species, or of migrants outside the migration season, typically contain fuel amounting to 3-5% of their lean body mass. Some

1The following terms are commonly used by researchers studying migratory fattening: live weight (of the living bird), fresh weight (of a carcass preserved without evaporative water loss, and therefore equivalent to live weight), dry weight (fresh weight minus the water component of the body), lean (or fat-free) weight (fresh weight minus the entire fat component of the body), lean dry weight (fresh weight minus the lipid and water components), and fat (lipid) weight (of the lipid component). In this field of study, the terms fat and lipid are usually used interchangeably (as here), as are the terms weight and mass, and body stores and body reserves. In the recent literature, the term mass is used much more often than weight.

Table 5.3 Mean body composition of migrants killed at a Television Tower at Tallahassee, Florida, and presumably about to cross the Gulf of Mexico in autumn


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