Regardless of its cause, the phenomenon has clear implications for conservation. Effective management of coastal habitats for migrants during stopover would enhance many songbird populations by improving survival of first-year birds. Long-term data from banding stations, however, tells us little about the process of bird migration, how the birds actually do the work of migrating. Much of my research in association with graduate and undergraduate students at URI is focused on this aspect of bird migration. Birds prepare for migration by increasing their body weight, sometimes by as much as 100 percent, while storing fat and protein.
Birds accumulate fat and protein reserves by eating more and by being selective in what they eat.
Migrating birds may increase their feeding rates fourfold. They are able to eat more food in part because the size of their guts increases. Without changes in their digestive system, the size of the gut would limit food intake and slow the accumulation of fat and protein reserves. Interestingly, this increase in feeding rate and gut size can be induced in captive migratory birds by decreasing daylight hours in the fall or increasing daylight hours in the spring. Seasonal changes in daylength initiate hormonal changes that mediate a host of physiological changes that include eating more, gaining weight, and flight activity at night.