Tuesday, May 13, 2008

Spring Birds

Nature Watch
May 13, 2008

By Susan Benson,
CNHM Director of Education

If you have bird feeders at home, this past week you might have found the songbirds “eating you out of house and home.” My parents are feeding at least a pound of bird seed a day. There are many species of birds at my parents’ bird feeders, and almost daily my mother lists off to me the birds she’s seen. Here’s a list of returned migrants and year-round resident birds list from one day this past week: song sparrows, white-throated sparrows, white-crowned sparrow, chipping sparrow, downy woodpecker, hairy woodpecker, mourning dove, purple grackles, slate-colored junco, Eastern towhee, chickadees, blue jays, American goldfinch, American robin, ruby-throated hummingbird (yes-they’re back!), red-bellied woodpecker, purple finches, cardinal, red-winged blackbird, evening grosbeaks, rose-breasted grosbeaks, Baltimore oriole, brown-headed cowbird, and red-breasted nuthatch. Species seen in their yard include a catbird, house wren, flicker and yellow-bellied sapsucker. Other species visiting include chipmunk, red and gray squirrel, cottontail rabbit and white-tailed deer. The striking blend of colors is a continued pleasure to the eye.

The particular species that caused me excitement while feeder watching this week included the rose-breasted grosbeak, evening grosbeak, and Baltimore oriole. Go outdoors and listen for the rich, warbling song of a rose-breasted grosbeak, sounding a bit like a robin that has taken singing lessons. These birds prefer to nest in deciduous woodlands, especially at the edges. They eat seeds, fruits, buds and insects. The nest, an open cup of sticks, twigs, grasses, decayed leaves, or weed stems, is lined with fine twigs, roots or hairs that they place in trees or shrubs. The nest of this grosbeak is so thinly constructed that the eggs can sometimes be seen from below through the nest. The male spends about 1/3 of its day participating in the incubation of the eggs. When you hear the male, it probably means it is near or actually on the nest.

The large, stocky finch with a bright yellow back, rump and underparts, is the evening grosbeak. Their song, a series of short, musical whistles, appears not to be used in the functions of mate attraction and territory defense. Evening grosbeaks nest in coniferous forests, built mostly by the female and constructed loosely from sticks, moss, lichen and rootlets. The inside can be lined with grasses, roots, lichens, hair and plant fibers. Evening grosbeaks feed on a wide variety of natural foods such as seeds (especially maples,) small fruits, insects and other invertebrates. Some years you may see flocks at feeders, while in other years they stay further north and are not seen in their winter range. Results from the Christmas Bird Count show that the evening grosbeak is an irruptive species across much of North America. Long-term research shows that these birds exhibit a biennial pattern of irruption; plentiful years followed by years when low numbers are reported.

I squealed with delight this week at the arrival of the brilliant orange and black Baltimore oriole. This bird received its name from the fact that the male's colors resemble those on the coat-of-arms of Lord Baltimore, after whom the city of Baltimore, Maryland is named. Young male Baltimore orioles do not have adult plumage until the fall of their second year. In spite of this, some first-year males with female-like plumage succeed in attracting a mate. The orioles appetite consist of caterpillars, fruits, spiders, and nectar. Their gourd-shaped nest is hung from the thin branches or a fork in a tall tree, and is woven from hair and plant fibers. In our backyards, they can be enticed to visit feeders with oranges, nectars, grape jelly, or peanut butter. Most feeders are orange, as orioles probably recognize the color orange from afar, matching their own plumage; if they spot the bright orange color of an oriole feeder, they usually drop down to investigate.
While watching the orioles feed on oranges and grape jelly this past weekend, I started wondering: like many humans, can birds have a food allergy to jelly containing high fructose corn syrup? I looked to our regional bird expert, Laura Erickson’s birding blog, where participants recommended feeding only small amounts of natural grape jelly, real grapes, or grapes mashed in with jelly. One birder shared the following from Kent Mahaffey, manager of the San Diego Wild Animal Park: “Natural nectars contain 12% to 30% sugars, while jams and jellies are more than half sugar…We do our best for them when we stick as closely as possible to their natural diets.” Could it be that we need to shop at the nearest health food store for our birds as well?

Nature Watch is brought to you by the Cable Natural History Museum. For 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility in Cable at 43570 Kavanaugh Street or on the web at www.cablemuseum.org to learn more about exhibits and programs.

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