Folktales, myths, and natural history prose often describe one bird, arising from the ashes, turning into a beautiful swan, or learning to sing. More serious writings describe birds’ courtship, food, plumages, and nest construction. Today in the U.S., on average, one book a day with some sort of avian theme is published. Often missing in these writings is the real context in which birds live and confront the challenges of survival. Birds do not sing in a vacuum, forage at all-you-can-eat buffets, or build nests at random. They inhabit a locale with a complex set of physical features and share the space with many other organisms. Birds live and function in a vibrant community, without covenents or edicts, but certainly with restrictions.

            I taught field biology to budding elementary school teachers for many years, exposing them to all sorts of plants and animals and teaching them how organisms behave and interact in an ecosystem. My goal was for them to eventually be able to look at a forest or grassland or lake and see not just a field of green or brown or expanse of water, but to visualize a super-organism of intertwined individual lives, all striving to pass the tests of survival in an environment of continual challenges. That’s the goal of this chapter – to try to peel back the veneer of descriptive natural history and expose the dynamic workings of avian communities.

Alexander von Humboldt wrote of the spectacular sounds and sights of the tropical forest and speculated that the trees and understory are so dense “that there was simply no room to add another plant.” Early naturalists wrote about the flashing specks of light filtering through the thick canopy onto the forest floor, oppressive humidity, hordes of army ants following undulating trails over thin soil, magnificent butterflies, enormous buttress roots supporting trees reaching to the sky, thorny palm trees, and masses of intertwined vines. And birds of every color, shape, and voice.  The environment presented squawking parrots in the canopy, antbirds in the litter, brown creepers on tree trunks, toucan bills jutting out of tree cavities, and hummingbirds flitting around dazzling flowers. Natural selection refined the adaptations of these birds of the tropical forest; few of them could survive elsewhere. Every habitat, every location, has its own defined set of birds- its avifauna. The individual members of the avifauna do not act singly and unfettered; they are evolutionarily obliged to confine themselves to certain roles (niches) to survive.

The arctic tundra, Namibian desert, Lake Baikal, and the boreal forests of Canada are all ecosystems and as such have much in common. Each ecosystem contains a unique collection of organisms surrounded and constrained by a distinctive set of physical elements– soil, weather, water, topography, and geology. An ecosystem – a collection of organisms interacting with each other and the physical environment - results from the gradual arrival and incorporation of different species, each one possessing its own physical, physiological, and behavioral attributes. A group of living organisms in any area constitutes a community; it may be an insect community, a plant community, or a community of birds, the avifauna. Communities are not random assemblages of organisms – they evolved over very long periods of time as each species in the community fit itself into the mosaic of the ecosystem piece by piece.

In a human context, a community is a group of people living in a particular location. The idea of community conveys the various roles that individuals play, such as shopkeepers, teachers, construction workers, firemen, and doctors. In the beginning a community might be rural with few people and the only doctor a general practitioner. As the community grows and becomes more complex, more roles are added and existing occupations become more specialized. Now there are pediatricians, surgeons, and ophthalmologists, as well as family doctors. Ecosystems and avifaunal communities develop similarly.