WILD ABOUT BIRDS: On orioles and cowbirds | PostIndependent.com

WILD ABOUT BIRDS: On orioles and cowbirds

Larry Collins
Free Press Home & Garden Columnist

Brown-headed cowbirds have some very strange yet interesting tendencies. So strange, they are worth mentioning.

Some birders feel they should be named the “Bison Bird” for its pre-settlement role in following the constantly moving herds of bison on the Great Plains while feeding on the insects that they dislodged from the vegetation. This nomadic lifestyle was not conducive to nesting in one place, thus they evolved into a parasitic nester. A parasitic nester is a bird that lays her eggs in another birds nest to be hatched and raised by the other bird.

Since cowbirds are raised by different species, they do not imprint on their biological parents. So how do they recognize their own kind for mating? Research suggests that young cowbirds might actually look at their own feather coloration and then seek out other birds that look like them.

Orioles are another species becoming quite abundant in this area. Have you noticed a large orange, white, and black bird trying to drink from your hummingbird feeder? Chances are it could be an oriole.

Orioles are insect and fruit eaters. They usually stay hidden in the trees eating and singing their beautiful whistling notes. They can be drawn down from their perches with foods like orange slices, grape jelly, mealworms and nectar feeders. When not feeding on nectar, orioles seek out caterpillars, fruits, insects and spiders. Bullock’s orioles may feed almost entirely on grasshoppers when they are plentiful; one bird was found to have feasted on 45 of them in one day. While in their tropical winter habitats, orioles feed on nectar from numerous flowering trees, which explains their attraction to nectar feeders upon their springtime return to North America.

While in their tropical winter habitat, the Baltimore and Bullock’s oriole play an important role in pollinating several tree species as they transfer pollen from tree to tree while eating nectar from their flowers.

The oriole nest is an engineering masterpiece. They weave a hanging-basket nest with plant fibers, grasses, vine and tree bark and sometimes string or yarn placed out on the small twigs of a branch 6-45 feet in the air. This type of nest helps keep them safe from most predators. It can take as many as 12 days for an oriole to weave its nest. One Baltimore oriole was observed spending 40 hours building a nest with about 10,000 stitches and the tying of thousands of knots, all with its beak. The female Bullock’s oriole is the primary nest weaver, but she may get some help from her mate in both the weaving and collection of nest material. Only the female incubates and broods, while both feed the young. Modern-day oriole nests are made primarily of plant fibers, whereas oriole nests collected in the late 1800s, before the age of the automobile, were made almost exclusively of horsehair.

Orioles will lay four to five eggs anywhere from April to June. The young will fledge as late as 30 days from egg laying.

Orioles are found across North America in the summer. Some species winter in the tropics and others in Mexico. Most Bullock’s orioles spend their winters in central and southern Mexico, with a few staying along the coast of Southern California. Both the Bullock’s and Baltimore orioles start their southerly migration as early as July, with August being the prime migration month. Both migrate at night and are known to be victims of collisions with buildings and communication towers.

The Bullock’s oriole was named in honor of William Bullock and his son, also named William, for their ornithological work in Mexico in the early 1800s. The Baltimore oriole, found in the east, and the western Bullock’s oriole were once considered to be the same species under the name Northern oriole. While they do inter-breed in areas where their ranges overlap, genetic studies have shown them to be two distinct species.

The Bullock’s oriole is the most common visitor to this area, while the Orchard and Hooded orioles are infrequent visitors. The Scott’s oriole passes through this area during their spring migration and has been known to be a summer resident. Baltimore orioles have never been seen in this area.

Local bird expert Larry Collins owns Wild Birds Unlimited, 2454 Hwy. 6&50. Email your birdfeeding and birding questions to lcollins1@bresnan.net.

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