Background Reading on Birds:
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.
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.
Its 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.
Mixed Evergreen Forests
Oak Woodland and Oak Savannah
Bishop Pine Forest
Coast Redwood Forest
Grassland
Coastal Beach-Dune Vegetation
Northern Coastal Scrub
Coastal Salt Marsh
Coastal Riparian Forest
Freshwater Marsh
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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