According to University of Rhode Island researcher, physiological ecologist Scott McWilliams, the digestive systems of birds adjust to meet the changing energy demands of migration. The birds’ bellies increase in size and the cells get larger so they can eat more and store energy for their long flights. The digestive systems of migratory birds essentially shut down during migration so most of their energy can be used in flight. When they stop to eat along their routes, they eat less, until finally their systems re-adjust when they arrive at their destinations where food is plentiful again.
As birds migrate, what food do they need?
Migrating birds require foods high in protein and low in fat. To help our feathered friends have a successful migration, we should fill our feeders and plant our yards with shrubs and seeds that contain higher amounts of protein. Try hanging some suet feeders stocked with suet cakes that contain high-protein ingredients such as shelled peanuts, sunflower kernels, shelled pumpkin seeds, rendered beef suet, pecans, and pistachios.
In addition to high energy food, like suet and Lyric Delite, which contains high protein shelled peanuts, sunflower kernels, tree nut pieces, and shelled pumpkin seeds, you can encourage migratory birds to use your yard as a stopover by offering everything they need for refueling. Think of the fueling and watering stations that appear at various milestones along the route of the New York Marathon. Your visiting marathon flyers need water, cover, and berries, available either in trees and shrubs like dogwoods, holly, viburnums, American highbush cranberry and service berry. They also need insects. Birds will seek out the insects in the mulch of leaves, so keep a pile in the corner of your landscape, and do not deadhead perennials like coneflowers and sunflowers, so these travelers will have plenty of high protein seed to eat as well. Keep your feeders filled with a variety of seed along with cut or dried fruit.
When will you see these long distance flyers?
When the seasons change, look up! Birds will begin to migrate when food sources diminish. Food that was abundant in summer in your area may not be available in the autumn so the birds previously feeding on these supplies will fly toward the equator where food is more plentiful. They often breed north in the summer and then spend the non-breeding season in warmer climate. They will only migrate if the quality and quantity of the food source at their target destination compensates for the energy it takes to get there and the risk of becoming prey. Many birds are migrating earlier now as temperatures warm along the East Coast of the United States. However, no matter where they fly or how far, it is a challenge for them to keep up with the earth’s rapidly changing temperatures.