Oriole native to Mexico found in Berks County

Black-backed Oriole in Berks County (from the Reading Eagle)

A male Black-backed Oriole, a native of central Mexico, is creating a stir in Berks County.

A bird is being seen at backyard feeders along Indiana Street in Heidelberg Township near Sinking Spring. If the sighting is validated, this would be the time the bird has been seen in the United States. A Black-backed Oriole was reported in southern California in 2000 but it was not accepted as valid because of a question of whether it was an escaped cage bird.

Rudy Keller, who compiles bird sightings for the Pennsylvania Ornithological Records Committee, theorized that a number of severe storms in the Pacific Ocean may have swept the bird far from its home range in Central Mexico, the Reading Eagle reported on February 4. Keller said the bird was in fresh breeding plumage and doesn't have the characteristics of a bird that escaped captivity.

Within two hours of news spread on the Internet, birders from as far away as Philadelphia and York lined the street, according to the Reading Eagle. Crowds gathered.

The bird is accessible but please follow these rules:

• Visiting hours are from 7:30 a.m. to 4 p.m. only.
• Park only on Indiana Street. Do not block driveways or mailboxes.
• Please don't stand in front of the house. It might scare the bird away from the feeder, which is located near the front window. The bird is shy.
• Please stay on the sidewalks and do not enter people's yards. Respect the neighborhood's privacy and property.
• Please sign the logbook. The homeowners are interested in knowing who visits the bird and where they come from.

The Black-backed Oriole is a neotropical bird native to the central plateau of Central Mexico, according to the Cornell Lab or Ornithology. During non-breeding season, the bird flies southwest to Oaxaca, in the the extreme southwest of the country. The species inhabits forests in arid to semi-humid environments, including riparian groves and pine oak forests.

Birders visiting the site (from the Reading Eagle)

The appearance is similar to that of the Bullock's Oriole except that the male Black-backed is mostly black on the back, rump and sides. The orange underparts of the Black-backed is yellower than in the Bullock's. Female and immature birds of the two species are comparable but the Black-backed's heads and sides are duskier. 

The birds' diet consists primarily of insects and spiders but they also consume fruit and nectar. They are one of the few birds able to consume Monarch Butterflies, which ordinarily are toxic to most predators. (The Monarchs spend their winters in central Mexico.) The Black-backed Orioles get around the problem by eating only the internal parts of the butterfly.

The Black-backed Oriole seems to be fairly common within its normal range, according to the Handbook of Birds of the World. The global population is estimated at somewhere between 50,000 and 500,000 individuals. 

The bird is protected in areas around Pico de Orizaba, a dormant volcano rising 18,000 feet above sea level. It is the highest peak Mexico and third highest in North America. The climate varies widely. The base of the volcano is a rainy semitropical environment, midway up is alpine vegetation. Nine glaciers originate at the northern peak.