Most neonatal mammals and many young birds require very different nutritional regimes than do their parents. Protein and energy needs are generally higher and are required as a greater percentage of the diet. Most songbirds and raptors fall into this category.
Adults capture or collect food and return it to nest basically unprocessed.
Other young birds are dependent upon provision of predigested or restructured foods. Doves, Pigeons, and some seabirds fall into this category. We covered diets for young and adults of this bird category in a previous lecture. Mammals Mammals by definition provide milk secretions as a food source for the neonate. The composition of milk varies tremendously between species.