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All species of plants and animals— including people—need a proper combination of food, water, cover, and space to survive and reproduce.
Together, these elements make up a “habitat.” Without habitat, a species cannot survive.
Since bird species are so diverse in their forms and lifestyles, their habitats vary tremendously. However, regardless of location, be it sandy seashore, tropical forest, arid grassland, or urban neighborhood, a habitat must fulfill four essential needs.
FOOD
Some species of birds are herbivores, eating seeds, fruits, buds, or flowers. Some are carnivores, eating insects, snails, fish, other birds, or carrion.
Many species are omnivores, eating both plant and animal matter. A bird’s bill shape and size offer excellent clues to the bird’s diet. The type of food that a bird selects depends on availability, and on its nutritional requirements, which change with season and age.
Breeding adults and developing chicks need additional protein, for example. Birds that eat plant matter much of the year, such as the American Tree Sparrow, will turn to insects to fulfill that need. Birds undertaking strenuous migrations will increase and alter their diets prior to their journeys in order to accumulate large amounts of energy in the form of fat. As an extreme example, the Blackpoll Warbler doubles its body weight prior to migration!
WATER
Birds, like all living things, require water. Most birds obtain water by drinking—dipping with their bills and tipping their heads back to swallow. Pelicans have been seen standing with their mouths open in the rain. Sea-going birds, such as albatross, can drink saltwater because of specialized nasal glands that extract excess salt from the blood.
However, species with very moist diets,such as hummingbirds and other nectar-feeders, obtain water almost completely from their food, and in very arid regions, some species also rely on metabolic water, produced as their bodies burn fat.
Water can also be essential as a medium for feeding and other activities. Herons wade, puffins dive, ducks dabble, and gulls skim the water in search of aquatic foods. Many birds stay on the water to rest, court, and preen. In fact, pelagic (oceanic) species spend most of their time out at sea, returning to land only to nest.
COVER
Birds need shelter from predators and the elements. Cover, including trees, grasses, and rocks, also harbors foods for birds and provides space or materials for nesting.
The requirements for cover can be quite specific. Species often show a preference for nesting and foraging at certain heights and in certain structures of vegetation. Cavity nesters, such as woodpeckers, require trees of the age and size to support suitable holes.
A bird’s needs may also change over time. Open meadows and grasslands provide good cover for wild turkey chicks; as adults, turkeys can better avoid predators in areas with mature trees and little underbrush. Some birds prefer no cover. Nesting terns require sandy stretches of beach nearly devoid of vegetation and use their bodies to shelter their eggs and chicks.
SPACE
Birds simply need the room to find food, water, and cover. The amount
of space needed depends largely on the availability of these elements. For
example, hawks and other raptors require more acreage for hunting when
the abundance of prey decreases. The need for space also mirrors the social habits of the species. In winter, Darkeyed Juncos flock together, but on their breeding grounds, these birds disperse and defend territories.
Most species of birds space themselves out for breeding, with males or breeding pairs defending their territory. In contrast, one-eighth of all bird species nest in colonies, including swallows, herons, gulls, and cormorants, and a large number of young may be produced in a small area. However, although a nesting colony occupies less space than if nests were widely dispersed, the birds often require large areas nearby in which to find food.
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Community care of local bird habitat is essential for the health of our Important Bird Area system – and for the birds.
Nature Canada supports community-based conservation programs across Canada to further stewardship and restoration efforts. Your support of Nature Canada ensures that these conservation activities at IBAs in your community continue. Support our IBA protection efforts.
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This information was adapted from materials provided from International Migratory Bird Day.
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