According to The Cornell University Lab of Ornithology, "birds migrate to move from areas of low or decreasing resources to areas of high or increasing resources. The two primary resources being sought are food and nesting locations."
Migration is primarily about nutrition. Birds that nest in the northern hemisphere migrate to where insects are most abundant and where leafy spring growth provides plenty of good nesting opportunities. When these resources wane and the temperature drops, these birds head back south. This pattern is true for the majority of the more than 650 species that nest in North America. Some species take this to the extreme, migrating thousands of miles from the Arctic all the way to South America and back.
Tracking bird populations helps study the long-term health and status of bird populations across North America. In fact, data compiled from many years of the Christmas Bird Count showed scientists that due to warming winters (WHERE?), more and more hummingbirds are staying south permanently, rather than migrating north.
While anyone with a flower garden knows that some hummingbirds tend to be year-round residents in Orange County, migratory species offer special seasonal birdwatching opportunities. Any activity in the Irvine Ranch Natural Landmarks can be a "birding" activity, to celebrate and observe the fall migration there are six special programs being offered through December designed to seek out these migratory birds. Visit www.LetsGoOutside.org/activities to register for one of these programs – binoculars are provided if you need them.
Here is a preview of a few of the feathered friends you might see in the Natural Landmarks this fall:
· Sightings start in mid-September, prevalent by October
· Adults have black and white parallel stripes running along the top, or crown, of their head
· Cornell Bird Lab Cool Fact: A migrating White-crowned Sparrow was once tracked moving 300 miles in a single night. Alaskan White-crowned Sparrows migrate about 2,600 miles to winter in Southern California.
· Sightings begin around the first weeks of October.
· Named for the bright yellow patch of feathers that grows where their tail meets their body.
· Large flocks of Yellow-rumped Warblers often contain smaller numbers of other warbler species that flock with them for safety.
· Cornell Bird Lab Cool Fact: The Yellow-rumped Warbler is the only warbler able to digest the waxes found in bayberries and wax myrtles. Its ability to use these fruits allows it to winter farther north than other warblers, sometimes as far north as Newfoundland.
· The Dark-eyed Junco is actually a type of sparrow.
· While a few hang out in this area year round, most of them don’t show up until mid-October.
· In this area, they are often seen foraging in small flocks on lawns and under oak trees.
· Cornell Bird Lab Cool Fact: The Dark-eyed Junco is one of the most common birds across North America, and a recent estimate set the junco’s total population at approximately 630 million individuals.
· Cedar Waxwings are often considered one of the prettiest of our winter migrants.
· They are often seen in flocks in berry-producing plants and trees, like Toyon.
· Their very high-pitched whistling call that may be out of hearing range for some folks.
· Cornell Bird Lab Cool Fact: The Cedar Waxwing is one of the few North American birds that specializes in eating fruit. It can survive on fruit alone for several months.
· Western Tanagers are one of the most colorful birds that migrate through Orange County.
· The Western Tanager travels farther north to breed than any other of its mostly tropical family.
· Cornell Bird Lab Cool Fact: The red pigment in the face of the Western Tanager is rhodoxanthin, a pigment rare in birds. It is not manufactured by the bird, as are the pigments used by the other red tanagers. Instead, it must be acquired from the diet, presumably from insects that themselves acquire the pigment from plants.