Background Reading on Birds

The Role of Birds in Their Habitat

Birds are dependent on their habitat and its natural community. In turn, the natural communities depend on bird species found in that habitat. A community refers to the complex web of interrelationships existing between the groups of plants and animals in a habitat. Let's consider the role of birds in one type of habitat, for example, riparian habitat.

Riparian habitats border the edges of streams and rivers. They comprise the area between the stream and the rest of its watershed. Riparian forests support the greatest total number of plant and animal species.

More birds - over 135 species - depend on riparian habitat during their lifetime than on any other kind of habitat in all of California. Why? This habitat has it all: water, shelter in lush forests, lots of layers, and an abundant food supply.

Some birds depend on a riparian habitat for their survival year round. Others depend on riparian areas for part of their yearly cycle - for example for feeding, resting, and for shelter during their migratory period. Some use riparian habitats only during the breeding season.

Birds provide a variety of services within the natural community of a riparian area. They can be seed dispersers and pollinators. Their waste products add nutrients to the soil. Woodpecker holes provide shelter for other species that can't make their own. Birds can be food for creatures high on the food chain such as a Song Sparrow eaten by a Copper's Hawk. They can help control population numbers of creatures lower on the food chain like a Yellow Warbler eating a caterpillar.

Different species of birds utilize different food sources. Their beaks and feet are adapted in a variety of ways to allow them to do so. In learning about the birds mentioned in this project, be sure to look carefully at the type of beak and feet a birds has, and how that relates to what it can or can't eat in their habitat.

Birds in Your North Bay Watershed Neighborhood

Do you live in the San Francisco Bay Area? Then you live in a watershed. A watershed extends from the ridges above a stream or creek and includes the habitats where water flows down into a creek or stream that drains out into the Bay (or some other major body of water.) A watershed includes all the plants, animals, and people who live in it, as well as the non-living components like rocks and soil.

Keeping our watershed healthy is important to keeping ourselves healthy. Keeping our watershed healthy involves making sure the water stays clean and preserving local habitats for the natural diversity of native plants, birds, and other animals.

Birds are found in all areas of your watershed - at the ridge tops, in vegetation along the sides of the creek, in grassy fields, down along the muddy shoreline and marshes, and out on the San Francisco Bay waters which eventually flow under the Golden Gate into the Pacific Ocean. By learning about local birds and their habitats, you can learn a lot about your own watershed.

Habitats in Marin County

The type of plant community often classifies a habitat. The distribution of birds is closely related to the distribution of plant communities. Plant communities are often referred to by the type of plant that give the habitat its distinctive appearance. An excellent reference is "Plant Communities of Marin County" by W. David Shuford and Irene C. Timossi published by the California Native Plant Society. Below are the plant communities listed in that book.

Important Words to Know

Habitat: the environment where a plant or animal lives and get all its needs to survive.

Watershed: the land area from which surface runoff drains into a stream channel, lake, bay, or other body of water.

Plant community: an association of plants, each occupying a certain position or niche, inhabiting a common environment and interacting with each other.

Food chain: the transfer of food energy from the source in plants through a series of animals, with repeated eating and being eaten.

Riparian: the area of vegetation along a stream bank.

Pollinator: an animal that transfers pollen from the male part of a plant to the female.

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