Selasphorus hummers at UC Botanical Gardens
Mon, 11 Oct 1999 08:47:49 -0700
From: Tom Condit
On Saturday morning, October 9, there were at least a dozen Selasphorus hummingbirds at the Mesoamerican hill in the University of California Botanical Gardens, Centennial Drive [east of campus], Berkeley.
There were also about half a dozen Anna's Hummingbirds and two or three small hummingbirds I couldn't identify. They were so little I thought they were Calliope Hummingbirds at first, but on closer examination they weren't. Very small, all green back, dark streaking on throat, pale breast and belly. Do Black-chinned Hummingbirds ever migrate through here?
Reply #1 Reply #2 Reply #3 Reply #4 Reply #5 Reply #6 Reply #7 Reply #8 Reply #9 Reply #10 Subject Index
Re: Selasphorus hummers at UC Botanical Gardens
Mon, 11 Oct 1999 09:38:06 -0700
From: Rusty Scalf
I should think that Costa's Hummingbird cannot be discounted either. Does anyone have advice to give for distinguishing female/young Black-chinned Hummingbird from Costa's in the field? There is a vocal difference, but that's not helpful if they're silent.
Rusty Scalf
Original Message Next Reply Subject Index
Re: Selasphorus hummers at UC Botanical Gardens
Mon, 11 Oct 1999 11:16:41 -0700
From: Joseph Morlan
Rusty Scalf wrote:
Does anyone have advice to give for distinguishing female/young Black-chinned Hummingbird from Costa's Hummingbird in the field? There is a vocal difference, but that's not helpful if they're silent.
I think Costa's averages a much duller gray-green above, and they are usually pretty vocal. I don't recall a completely silent one.
Black-chinned average a brighter more glittering green above compared to Costa's. They also often seem to show considerable buff on the underparts which I don't usually see on Costa's. Black-chins often give a deep wing-whurr sound that I don't hear from the others. I'm not sure if it's made by the wings or tail. Anybody know?
Lastly, Costa's tends to have a shorter bill and a meaner look in their eyes, than Black-chinned. Black-chinned seems to me to pump its tail more deeply and deliberately than the others.
The Black-chinned Hummingbird was formerly thought to be a very rare visitor to Santa Clara County, but work by Steve Rottenborn and others have shown that it is actually a fairly common breeder in riparian corridors in the Santa Clara Valley. Nevertheless its status in Alameda County remains very rare. I've never seen it in the county and it remains very rare in Contra Costa outside the extreme northeast corner of the county, where it is well established.
Now let's get out there and find that Ruby-throat! ;)
Joseph Morlan, Pacifica, CA 94044
California Birding; Mystery Birds: http://fog.ccsf.cc.ca.us/~jmorlan/
California Bird Records Committee: http://www.wfo-cbrc.org/cbrc/
Original Message Next Reply Subject Index
Re: Selasphorus hummers at UC Botanical Gardens
Date: 11 Oct 99 12:00:38 -0700
From: Les Chibana
[Reply to Tom's original question.] Black-chinned Hummingbirds nest in several riparian areas in the South Bay. So, it's highly possible for them to be around either as dispersals or migrants, but this date might be late for them. Dark streaking on the throat and pale breast doesn't seem to fit Black-chinned. I would expect a clean, bright white throat. Caveat: I don't have enough experience with immatures for a good mental image. I would also look for a longer bill than Anna's with a slight but noticeable decurvature.
I haven't seen enough Costa's, young or adult, to comment on Rusty's question.
Les Chibana
Palo Alto, CA
Original Message Next Reply Subject Index
Re: Selasphorus hummers at UC Botanical Gardens
11 Oct 99 12:28:45 -0700
From: Les Chibana
Joseph Morlan wrote:
... Black-chinned average a brighter more glittering green above compared to Costa's. They also often seem to show considerable buff on the underparts which I don't usually see on Costa's. Black-chins often give a deep wing-whurr sound that I don't hear from the others. I'm not sure if it's made by the wings or tail. Anybody know?
Oh, yeah, good point about the flight sound! I often detect Black-chins by their characteristic buzz, which is not as sharp and metallic like Selasphorus but sharper than the Anna's hum. My impression is that this is a wing-generated sound, because I hear it associated with flight acceleration. Doesn't seem likely that the tail could produce the sound under these circumstances. Their vocalizations are a characteristic, quiet "tew" as noted in field guides. I've only heard them vocalize in-hand or in-bag, though.
Les
Original Message Next Reply Subject Index
Piper Slough
Mon, 11 Oct 1999 14:37:38 PDT
From: Steve Glover
Hello everyone,
The clear skies that have dominated recently continued today so I didn't expect much in the way of migrant passerines. And I didn't get many. Still, there were some interesting birds about.
At Piper Slough on Bethel Island there were, in no particular order, the following:
Common Raven (1)
Tree Swallow (75)
White-crowned Sparrow (44) Both pugetensis and gambelii
Orange-crowned Warbler (5)
Virginia Rail (3)Marsh Wren (7) This may be my high here and indicates a substantial movement of this species. I normally get 0 to 2.
Lincoln's Sparrow (5)
Hermit Thrush (4)
Yellow Warbler (5)
Pied-billed Grebe (35)
Forster's Tern (22)
Sandhill Crane (Heard to the north at Webb Tract but not seen)
Bufflehead (One early female)
Green Heron (1)
Wilson's Warbler (2)
Black-throated Gray Warbler (1)
American Pipit (2)
Fox Sparrow (2)
Barn Swallow (5) All heading southwest. The summer nesters have cleared out.
Barn Owl (1)
At Clifton Court Forebay, the lack of wind made scoping conditions pretty good. There has been a substantial movement of American Coots with 4200 today. There were also 225 Ruddy Ducks, 125 Aechmophorus Grebes, one Eared Grebe, and a very early female Common Goldeneye. I wouldn't have expected the goldeneye for another couple of weeks, but then again Common Goldeneyes rarely get reported. My files culled from various sources contain 5.5 pages of Barrow's Goldeneye sightings and only 0.75 page of Common Goldeneye sightings. A typical Barrow's arrival date seems to be in the neighborhood of Nov. 4 to 8.
Finally, a note on Cliff Swallows. There have been a couple of reports in the last week of Cliff Swallows or possible Cliff Swallows. In the past couple of years there have been a few October records of Cliff Swallow in Northern California, but they are still very rare by this time. Most of our breeders have departed well before September. Basically I'm not saying that I don't believe claims of Cliff Swallow in October (I had two at Miller/Knox Regional Shoreline on 10/17/96 that I was actually able to look down on), but everyone should be aware of the status of this bird so late and know that they should be looked at carefully and identified with certainty.
Steve Glover
Dublin
Re: Selasphorus hummers at UC Botanical Gardens
Mon, 11 Oct 1999 17:48:48 -0700 (PDT)
From: Richard Mix
I don't think we saw the mystery birds, but for what it's worth, Ann Callaway and I took a few moments and slipped into the botanical gardens today at 4:00 (admission is free 45 minutes before closing). In the shade at bed 603 we were surrounded by hummers, as well as chickadees and goldfinches drinking out of the sprinkler. One interesting bird looked like a possible Black-throated, but Ann thought there was a flash of red when it flew away. We saw a variety of Selasphorous, including a totally orange male - even the crown was rufous. The gorget, when it caught the light, was more copper colored than the usual fire-orange, so in the shade I might, I suppose, have missed a hint of green in the grey border between the back and the white underparts. As I recall, 70% green-backed Rufous and/or 70% red-backed Allen's have been documented; is there any chance this individual could be an unambiguous Rufous?
Richard Mix, El Cerrito
Original Message Next Reply Subject Index
Re: Selasphorus hummers at UC Botanical Gardens
11 Oct 99 19:45:49 -0700
From: Les Chibana
Richard Mix wrote:
One interesting bird looked like a possible Black-throated, but Ann thought there was a flash of red when it flew away.
Do you mean Black-chinned, as in, Hummingbird?
is there any chance this individual could be an unambiguous Rufous?
I think that the only unambiguous Rufous Hummingbird is a male with an entirely rufous back. You might have high confidence in a Rufous identification if the green in the back appears as isolated flecks in a mostly rufous back. I'm not sure that you would see a gray border between the back and underparts (do you mean the flanks?). I think Selasphorus usually show some degree of rufous in the flanks. Gray in this area implies Anna's, to me.
Mike Patterson, up in Oregon, did a study of back color in Rufous Hummingbirds in 1990 [Oregon Birds, 16(3):218-222]. He felt that most male Rufous showed some amount of green on the back. He had a system of scoring the amount of green by dividing the back into quadrants and averaging them. He confirmed the species identification by way of tail feather shape (R2 notched and emarginated in Rufous), width of the outermost tail feather (R5 greater than 2.7 mm), and I don't recall any other keys right now. His sampling was 37 male Rufous that keyed out well within the proper range. His results:
16% showed no green on the back
52.7% showed from 1 to 25% green
27.8% showed 26 to 50% green
One bird had nearly 70% green
He also checked with the collection at the National Museum of Natural History. The curator said that he found a few skins of Rufous that had green backs, including a couple that estimated in the 51 to 75% green range. Patterson felt that there was evidence to suggest that these green-backed individuals were first alternate males, that is, males in their first season as a breeding adult. He also felt that the Rufous hummers from the more northwestern extent of the breeding range showed more green on their backs.
I wonder if any systematists are planning to use some kind of genetic analysis to compare Rufous and Allen's. Wouldn't it be interesting if they did and decided to lump them as two races of the same species?
Les Chibana
Palo Alto, CA
Original Message Next Reply Subject Index