Senior citizen hummingbirds and a "green-backed" Rufous
This weekend we banded birds at the house and in the wildlife shelterbelt leading to the orchard. We caught 62 hummingbirds, including 38 which were newly banded, and 24 recaptures from previous years. The new birds included 28 adult Black-chinned males, 6 adult females, 2 juvenile males, and 1 juvenile female. We also banded an adult male Rufous. Of the returning birds, 13 were male, 11 were female.
Two returning males had been banded as adults in July and August 2001, which means they are at least six years old now. So, they have flown to Mexico for the winter and back at least five times, possibly more. One of the birds had never been recaptured in the past five years, the other had been recaught only once, in 2002.
Also, two returning Black-chinned females had been banded as adults in June and July 2002, making them at least five years old. One of these is "Bronco Girl", so named for the orange and blue color marking which she has sported each year. She also has a unique physical characteristic, a lower mandible which is 2 millimeters longer than the upper mandible or maxilla. This characteristic has remained constant through the years and has helped us identify her in the field and to ascertain which nest locations she has used from year to year. We have recaptured Bronco Girl every year, a total of ten times.
According to the Bird Banding Laboratory's longevity database, the oldest known Black-chinned Hummingbird was 8 years, 11 months old at the time it had been re-encountered. Surely this qualifies these five and six+ year old hummers as senior citizens in the hummingbird world. But just because they are senior doesn't mean they're over the hill. Bronco Girl is currently incubating her second brood of the summer while still feeding her first brood young.
Finally, I'd like to share two photos of the male Rufous we caught yesterday. Most adult male Rufous have a more or less solid rufous colored back, some with varying amounts of green or partially green feathers. It is how one can tentatively ID a male Rufous over the similar male Allen's Hummingbird, most of which have green backs. But the stickler is that some Rufous have more green than rufous, and some Allen's have significant amounts of rufous in the back. What's more, both birds have rufous upper tail coverts, and determining where the back feathers end and the upper tail coverts begin isn't so easily done. In the field, these birds can look identical. So, a careful examination of the bird including shape and measured width of the R2 and R5 tail feathers is necessary to positively ID these green-backed Rufous/Allen's. With females and immatures, details are even more difficult so an in-hand examination is necessary.
Note the bird in the photo has a lot of green in the back, enough that when seen on a perch or feeder, a sharp-eyed birder might reasonably call it "a possible Allen's Hummingbird". We have banded many Rufous that look like this. But like the others, the deeply emarginated or notched R2 (second retrice or tail feather out from center two), reveals this is what I would call a "green-backed" Rufous. Also, his R5 or outer tail feather, measured 2.74 mm at the widest point, more than twice the width of an Allen's R5. I think early summer is a good time to find an Allen's in Colorado. If you see a likely candidate, please give me a call. Together, we may be able to verify a questionable Rufous/Allen's hummingbird.
********************************** Steve & Debbie Bouricius 3412 C Road Palisade, CO 81526 970-434-5918 Hummingbird Orchards ....Banding and Research Station USGS Bird Banding Laboratory permit #23198 CDOW Scientific Collections permit #06BD834 NABC certified master hummingbird banders **********************************