RTHU Study

Rufous Hummingbird banded 11-25-2008 from Montgomery, Ohio

Rufous Hummingbird banded 11-30-2007 in Springfield Township, OH.

Rufous Hummingbird

photo courtesy Bob Foppe

Small, centralized patch of dark, "bronzish", or in this case, more red as you can see by the one gorget feather spread open on the finger. Not as "ruby" as a Ruby-throated Hummingbird.

This bird has an unusual molt limit. The primaries (outermost wing feathers) and secondaries (innermost wing feathers) are dull and worn. More study is being conducted on this. It is not common this time of year and more data is needed to understand the molt sequence of this bird which, among other things, could help age these birds more accurately.

The tail feathers are one of the "definitive" indicators differentiating Allen's with Rufous. From left to right, tail feather 5 is much wider than an Allen's ... only detectible with measurements in-hand. Tail feather 2 (from left to right starting with the number 5) has a slight notch, or in this case a "dip" at the tip. Some Rufous show a more distinct notch. Allen's also will "usually" lack any significant rufous coloration on feather 1. There is some showing on tail feather 1 (center green one) near the thumb.

Other indicators that separate Rufous from Allen's are wing length, tail length, and culmen (bill) length.

Rufous are larger than Allen's. Larger is relative as it is only by mm differences.

This bird weighed 3.75 grams.

About 1 gram more than a copper penny!

In-flight, because of it's fast movement, the bird photographed below had enough oddities to fool even the best of birders into thinking it could be a western hummingbird. The molting rump, coverts and tail looked, in flight, very much like a Calliope hummingbird. Even photos of the bird hinted a Calliope, and even a tropical species. Along with it's atypical Ruby-throat behavior, it left us wondering until we captured and banded the bird. It turned out to be a Juvenal Male Ruby-throated Hummingbird with a very late molt of it's entire bottom half of it's body.

Male Juvenal Ruby-throated Hummingbird banded 10-18-07. The entire rump and all the upper tail coverts and tail feathers are molting. Mostly what is showing are pin feathers (feathers with the plastic-like covering still over the majority of the incoming new feathers).

We are not sure why this bird is going through this type of pre-basic molt so late. Nearly all the Ruby-throats have left our area while this one still has some time before his feathers are ready for the long flight.

The bird was healthy with a considerable amount of fat stored up. It's ready to migrate, but the feathers are not.

Notice the small red spot at the base of the throat. This shows the typical beginnings of a red gorget on a male. This, along with the darker streaks, makes this bird a young male. (there are other plumage characteristics taken into consideration when aging/sexing a bird in-hand)

Measurements in-hand confirm all the visual identifiers for species and sex of the hummer. There are times when measurements are the only way to differentiate, without a doubt, certain species of hummingbirds. Especially in the winter months.