Where are Baltimore Orioles?

Do orioles breed in Massachusetts?
Baltimore orioles breed throughout North America, east of the Rockies. Orioles winter from Florida to Jamaica, and from southern Mexico to northern South America.

Northern migration begins in February. Baltimore orioles generally arrive in Massachusetts during the first week of May.

The preferred breeding habitat for Baltimore orioles is open deciduous woods with edges, including suburban and urban sites. For nesting, the birds prefer tall elms, sycamores, cottonwoods, and maples.

The birds depart Massachusetts in early August (immature birds in late August-September) and arrive on wintering grounds from late August to mid-October.

After the Fall
A great time to find oriole nests you missed during the breeding season is to wait until just after the leaves are off the trees and then explore likely habitats. Later in the season nests are often blown down by successive storms, but they are often quite conspicuous in November and December.

Where do Massachusetts Orioles go in the winter?
It's not that hard to figure out where Baltimore Orioles as a whole spend the winter. All you need is the price of a plane ticket to Mexico, Colombia or somewhere in between and a decent pair of binoculars. Nowadays, gringo birders, visiting the many hot birding venues in the Neotropics may see more Baltimore Orioles sipping tropical nectar from flowering trees in a few days than they see in a whole season at home.

Discovering where Massachusetts orioles spend the winter, however, is a much knottier problem, requiring the tracking of individual birds from nesting grounds to winter quarters. In the not very distant future, we will no doubt be able to harmlessly implant tiny transmitter chips in the smallest of songbirds and follow every zig and zag made by these remarkable migrants. But for now we continue to depend on the efforts of hundreds of bird banders, to capture their subjects in mists nets and attach lightweight aluminum rings to their legs in the hope that someone else somewhere else will read the number on the band and report back.

Quite a lot of birds have been banded in Massachusetts, so we e-mailed Kathy Klimkiewicz of the Bird Banding Laboratory at the USGS Wildlife Research Center in Patuxent, Maryland to see what is known about the travel itineraries of "our" orioles. The result sharply clarifies the magnitude of the challenge. Of the hundreds (thousands?) of orioles banded in Massachusetts since the 1920's, only 69 were ever recaptured and the great majority of these were re-netted back in Massachusetts, mostly at the same banding station where they were first trapped. Only two of the banded orioles were tracked to the Neotropics. One was a first year bird "caught due to injury" in the foothills of the Sierra Madre Oriental not far from the village of Tlapacoyan in the state of Veracruz, Mexico; that it was found in early September suggests that it may not have reached its final destination. The other, an adult male shot in November about 17 miles SE of Oaxaca may have succumbed in its winter home.

This doesn't tell us a great deal - we don't even know if the ill-fated orioles nested in the Commonwealth - and it took an awful lot of work to come up with these two records. But there something a bit thrilling about firing up Google Earth and verifying with your own eyes the "miracle of migration."