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Master Naturalists: Not your 'usual' hummingbird

By By Paul and Mary Meredith
Dec. 19, 2013 at 6:19 a.m.

Buff-bellied hummingbirds, like this one on a feeder outside our kitchen window, overwinter on the Texas coast.  They generally do not migrate south as most other summer-resident North American hummingbirds do.  Some do migrate from their nesting grounds in our part of Texas, but they go east - as far as western Florida.  Rarely, they are spotted wintering in south Georgia.

A buff-bellied hummingbird (once known as fawn-bellied) visits our feeders daily this winter. One feeder hangs just outside our kitchen window. We're enjoying watching him and learning more about Amazilia yucatanensis (his species).

He attracted our attention this fall because he is noticeably larger than the migrating ruby-throated and other migrating hummers we often see. And he's not shy. He eats, then sits (yes, sits) and looks around (including at the window where we stand watching), then eats again. He's in no hurry to leave.

How to tell it's a buff-bellied hummingbird

An adult buff-bellied male is described as "dark-greenish overall with a rusty-brown, (or 'rufous'), tail." He also has a "rich buffy-colored belly, glittery green throat and upper parts and a conspicuous red bill with a dark tip." An adult female looks similar. They're described as "not shy."

Buff-bellieds are regularly found nesting in the Lower Rio Grande Valley and along the Gulf Coast up to about Victoria. Some don't migrate. A few have been reported wintering in Central Texas. Some migrate and winter eastward to western Florida.

Several other similar hummingbird species

Several other hummingbird species are similar enough to buff-bellieds, also known as buffies, to be confused with them. But their ranges generally do not overlap the buffies in Texas.

Beryllines look somewhat like buffies but have some differences. Emerald green (Berylline) is the main color of their head and throat, with gray bellies and a rusty "flash" from their wings.

Bills are "slightly drooped and darkish with hints of a reddish tone" versus buffies' red with a dark tip. Berylline sexes are quite similar, with females "less glittery green." They're native to West Texas, New Mexico and Arizona.

Rufous-tailed hummingbirds (Amazilia tzacatl) are also described as similar-looking to buffies. They're found from the Atlantic slopes of eastern Mexico from southern Veracruz on down throughout Central America to northern South America. Undocumented records of Rufous-taileds in southern Tamaulipas exist.

For that reason, in the Valley, vagrant rufous-tailed might show up and be confused for buffies. However, no documentation exists for "rufous-tailed" in the U.S. - except for two old records from southern Texas that could have been misidentified buffies.

Some authors report Amazilia (Amazilia a. Amazilia), a South American species that escaped from captivity in the U.S is similar, with a bright rufous lower breast and belly. Their bills look like buffys. They are an aggressive species, typically dominant on feeders and flowers in an area in their native Peru and Ecuador.

Fellow visitors to hummingbird feeder

The other regulars at the feeder are honeybees. They are attracted to a nearby Lantana but get on the feeder to clean up spilled sugar water. We have not seen them since the weather turned colder. Bees are cold-blooded insects, so they cannot fly in cold weather (below about 50 degrees).

In fact, they must shiver to stay warm in their hives under cold conditions. They are adapted to be able to temporarily unconnect their wings from their flight-muscles to shiver. When flying in cool temperatures, they will stop and tremble to heat back up. (Another fascinating subject, huh?)

Sources: Hummingbirds of North America, Sheri L. Williamson

Birds of Texas, Fred J. Alsop III

The Behavior of Texas Birds, Kent Rylander

http://scientificbeekeeping.com/old-bees-cold-bees-no-bees-part-2/

Paul and Mary Meredith are master naturalists. Contact them at paulmary0211@sbcglobal.net.

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