Piper Slough and odds and ends
Fri, 3 Sep 1999 14:14:51 PDT
From: Steve Glover
Hello everyone,
First the odds and ends from other recent postings.
As far as the Selasphorus hummingbirds go, it should be mentioned at this time of year at least most of the birds coming through will be female/immature types. This means that unless you do actually find an adult male you probably have no chance of telling them apart unless you can band them. There was a prominent bird bander on a boat trip I was on last week (he wasn't actually talking to me so I won't quote him by name) and he said that he suspects all Allen's are gone by late August.
Also in the hummingbird department, I had one each of Anna's Hummingbird and Black-chinned Hummingbird today (Sept 3) at Piper Slough. It is the former, surprisingly enough, that is more interesting to me. Larry mentioned in his post that he only had Anna's and nothing interesting. In my experience it is Anna's that is rare out there. I haven't gone through my notes yet from old trips but I doubt that I have recorded it out there more than about 5 times. Black-chinned is usually the only hummingbird out there, with Rufous being the second most often seen.
And finally, Ravens. They have without a doubt increased astronomically in just the past few years. I knew of 2 or 3 Contra Costa County nest records before the atlas started last year. We had nests in 13 blocks last year! I may have mentioned this before but in 1976 a pair was noted in Hayward and Berkeley from April 19 to April 21, leaving the regional editor to wonder if they weren't the same pair! That is how rare they were. Nowadays I don't always bother to write down birds that I see on the way to work or over my house, they are that regular.
OK, today at Piper Slough [on Bethel Island]. An interesting morning despite a decent breeze. In no particular order:
Tree Swallows are on the move, today I had flocks totalling 175 , all flying southwest. This is a common event out there and I always wonder how many birds are actually passing by to the east and west that I don't see.Willow Flycatcher was abundant today. I carefully counted 23 and there were likely nearly twice that. The old high was 22 at the same location on Aug 22 a few years ago. Many were calling.
Yellow-breasted Chat - One silent individual was present today, possibly a migrant rather than one of the local breeders.
Blue Grosbeak - Today there were still 2-3 female/immature types.
Western Tanager - One
Yellow Warbler - 13, but see the following.
Warbler Species - 51. I had warbler flight calls all morning but was able to get on very few of them. I suspect that the vast majority of these were Yellows.Pacific-slope Flycatcher - 2
Bullock's Oriole - 1
Chipping Sparrow - One adult. This is probably only the second time I have had this species there and the first for fall.Black-chinned Hummingbird - One fem/imm
Anna's Hummingbird - One fem/imm
American White Pelican - 18 drifting around, eventually drifted to the southwest.
Wilson's Warbler - 1
Townsend's Warbler - 1
Warbling Vireo/ 1
On Hwy J-4 just south of Clifton Court Forebay and just north of the line with Alameda County, there was an Osprey sitting on a telephone pole.
Steve Glover
Rufous Hummingbirds at UC Botanical Gardens
Fri, 3 Sep 1999 21:11:40 -0700 (PDT)
From: Tom Condit
I got intrigued enough by all the discussion about which Selasphorus species was around that I walked up to the UC Botanical Gardens in Berkeley, always a good place for this genus if they are in town.
At the Mesoamerican section about a dozen Selasphorus hummingbirds were flying about in and between Beds 359 and 360 (mostly Penstemons and Eupatorium). Of the ones which stood still long enough to be carefully observed all but one were definitely Rufous Hummingbirds. There was one in which I couldn't detect any red at all on the back.
Most of the Rufous hummers appeared to me to be immature males. They had a distinct area of streaking on the chin, with one spot right at the wishbone which flashed a bright ruby red in the right light. Several did a lot of posing on shrub tops, preening, etc., so I was able to get some pretty good views. At least one kept returning to the same perch the way Olive-sided Flycatchers do. There was also quite a bit of flying straight up for a few meters, then straight down, both individually and in pairs, and some chasing.
This spot is far enough from the road the traffic doesn't drown out the calls and chatter, of which there was a lot, so people better at birding by ear might be able to pin this down better.
Over in the area of New World Desert and the African Hill there was also a lot of hummer activity, but all those I could identify were Anna's Hummingbirds.
Other birds seen: Chestnut-backed Chickadee, Western Scrub-Jay, American Crow, Red-tailed Hawk, Bushtit, American Robin.
Saturday, September 4, is a football game day, so the garden will be inaccessible by car from the west, but you could drive down Centennial Drive from Grizzly Peak Blvd or walk up from Berkeley.
This weekend is the last of the summer-hours period, when the garden is open until 7 PM.
Tom Condit
Original Message Next Reply Subject Index
Re: Rufous Hummingbirds at UC Botanical
Gardens
Fri, 03 Sep 1999 22:22:05 PDT
From: Joseph Morlan
East Bay Birders,
Identification of this group is not straightforward. Birds with solid red upper backs are Rufous Hummingbirds, but birds with green upper backs may be either species. Females are essentially indistinguishable in the field and male Allen's broadly overlap variation in Rufous. Thus Allen's Hummingbirds (all ages and genders) are close to being impossible to identify with certainty in the field.
Some useful identification tips by Mike Patterson are at:
http://home.pacifier.com/~mpatters/archive/humm/hummtips.html
More detail with helpful photos are at:
http://www.talstar.com/users/conover/alhu.html
Even in the hand it can be difficult. Many years ago a student brought me a dead Selasphorus that flew into a window at Point Richmond in September. Suspecting it was a Rufous, I brought it to the California Academy of Sciences where Dr. Laurence Binford compared it with a series of specimens and diagnostic rectrices (A series of r5 from both species mounted on a card). The result: Inconclusive!
Hybrids have never been confidently detected, but with their morphology so similar how would one determine it? There is no pair bond and the females are essentially indistinguishable anyway.
I do not personally believe that these two are in actually valid species.
Joseph Morlan, Pacifica, CA 94044
Fall Birding Classes begin Sept 7:
http://fog.ccsf.cc.ca.us/~jmorlan/
California Bird Records Committee:
http://www.wfo-cbrc.org/cbrc/
Original Message Next Reply Subject Index
FWD: Eucalyptus and birds
Sat, 04 Sep 1999 08:31:13 -0700
From: Mike Feighner
Hello Fellow Birders:
The Calbird archive at
http://www-stat.wharton.upenn.edu/~siler/CALB.html
has not been updated in ages. So, Kimball Garret's latest post will not be in there. Apologies to those who regularly get posts through Calbird and to those who subscribe to more than one local listserv. I feel that Kimball's post is equally relevant to us here in the Bay Area. So, I am forwarding it in its entirety. Certainly you have heard through the news media about the insect pest that is affecting (and in some cases decimating) eucalyptus trees in Southern and Northern California. It is the Red Gum Psyllid, Glycaspis brimblecombei. The larvae of these psyllids excrete a small conical "lerp" (made of sticky, sugary "honeydew") that encapsulates the larva. An affected eucalyptus is easy to spot because of the sticky lerps on the leaves, a virtual "rain" of sticky honeydew from the tree, and, ultimately, lots of dead leaves and even complete mortality.
See Kimball's post below for more details on this insect pest and its impact on birds. See also
http://www.egroups.com/group/central_valley_birds/?isDecendingSort=0&searchStart=166&isThreaded=0&fetchForward=0&start=166
messages 160-163.
In the Bay Area I have noticed the Red Gum Psyllid in the eucalyptus trees in my yard in Livermore several days before the news hit the press. The grove of eucalyptus behind the Arco Gas Station in Livermore in Alameda County at Stanley and Murrieta are dying as well as the grove along Hwy I-680 in Fremont in Alameda County between Durham and Washington. Just yesterday I noticed the Red Gum Psyllid in the eucalyptus trees at the new south parking garage at the Valley Fair Shopping Center in Santa Clara County.
I haven't had time to check the trees in San Francisco County (Golden Gate Park and Stern Grove), San Mateo County (Crystal Springs Reservoir), other areas of Santa Clara County like Stevens Creek County Park and Saint Joseph's Hill Open Space Preserve, or the eucalyptus grove at Moon Glow Dairy in Monterey County. These locations all contain large groves of eucalyptus.
Mike Feighner, Livermore, CA
To: CalBird
From: Kimball Garrett
Subject: Eucalyptus and birds
Date: Fri, 3 Sep 1999 12:14:57 -0700Calbird:
Most of you are aware of the extent to which birds in the coastal regions of California exploit eucalyptus trees for nectar, particularly in winter. Searching groves of flowering eucalyptus has become a requisite modus operandi on Christmas Bird Counts, with the rewards often being good counts of overwintering hummingbirds, orioles, tanagers, grosbeaks, and wood-warblers. Given that eucalyptus are among the dominant trees in many urban and suburban regions of California, it is hard to imagine birding in the region before (and after?) the establishment of these exotic trees.
You might have heard of a recent insect pest that is affecting (and in some cases decimating) eucalyptus trees in southern California. It is the Red Gum Psyllid, Glycaspis brimblecombei. The larvae of these psyllids excrete a small conical "lerp" (made of sticky, sugary "honeydew") that encapsulates the larva. An affected eucalyptus is easy to spot because of the sticky lerps on the leaves, a virtual "rain" of sticky honeydew from the tree, and, ultimately, lots of dead leaves and even complete mortality. Infestations grow fastest in the warmer months, and are exacerbated by drought and other stresses. For example, Elysian Park (near downtown Los Angeles, and so productive last winter for orioles, tanagers, and warblers) has been severely impacted, with hundreds of apparently dying eucalyptus trees. Maintenance agencies will almost certainly cut down affected trees rather than risk injury to the public from falling branches, etc. Some eucalyptus species are more susceptible to this pest than others; impacted species include Red Gum Eucalyptus, sugar gum, blue gum, and a few other.
For more information on this pest, see the Los Angeles County Agricultural Commission's web site:
http://acwm.co.la.ca.us/Where it gets interesting is that there are entire guilds of birds in Australasia which exploit these lerps for food. Such feeding habits are especially typical of honeyeaters and pardalotes. I'm not suggesting that we import these birds, but it will be very interesting to see if our native birds will exploit this potentially abundant food source. So I urge all of you who bird in a favorite park or other site with infested eucalyptus trees to pay attention to this.
Furthermore, should this infestation result in widespread loss of large numbers of "our" eucalyptus trees, then the ramifications for overwintering hummingbirds, orioles, tanagers, and wood-warblers are potentially severe (though one might view this as more of a "readjustment" to pre-European conditions). These things are hard to monitor, so birders this winter should pay close attention to bird numbers in affected areas.
G'day,
Kimball Garrett**********************************************************
Kimball L. Garrett
Ornithology Collections Manager
Natural History Museum of Los Angeles County
900 Exposition Blvd., Los Angeles CA 90007 USA
213/763-3368 phone; 213/746-2999 FAX
**********************************************************