Re: Global warming and early shorebird migration
Sun, 11 Jul 2004 13:54:08 -0700
From: Rusty Scalf
Hello Phila,
I don't know about shorebirds, but I have read several places that day length (photo-period) is a probable pre-migratory stimulus in passerines. See this USGS web page, which goes into some detail, especially the third paragraph:
http://www.npwrc.usgs.gov/resource/othrdata/migratio/stimulus.htm
It does seem to me that springs have come earlier in recent years. But it's so hard to know, given how small our time slice is.
Rusty Scalf
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Re: Global warming and early shorebird migration
Sun, 11 Jul 2004 19:31:16 -0700
From: Mark Eaton
Actually, much more detailed studies have been done by climatologists and environmentalists investigating global warming. Among the many changes expected from global warming is earlier and earlier migrations and northward range expansion of a species breeding range. The really scary thing is that most of the models, even by the most conservative estimates, suggest that we're seeing only the beginning of this change and considerable northward shifts in the migratory birds in the next 25 years. Since plant communities are not capable of such rapid changes in this time frame, it's hard to imagine this not having a significant impact on some of these species.
I don't have any written references on this, but do have a program I recorded off of UC TV that might be of interest to folks on this list. Follow up off list...
Mark
Mark W. Eaton
Personal Web Site: http://www.markeaton.org
SFFO Web Site: http://www.sffo.org
SFBirds mailing list: http://groups.yahoo.com/group/SFBirds
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White-tailed Kites in Pleasanton
Sun, 11 Jul 2004 21:44:55 -0700
From: Rich Cimino
At 8 PM tonight (Sunday July 11) near the corner of Harvest Rd & Vailmeadows there were 7 White-tailed Kites gliding and hovering and in general what appeared to be loafing in the air, certainly in no hurry to go anywhere.
Then about 8:15 some 50+ Crows launched themselves from the cottonwoods lining Del Valle Creek and flew into the kites. The kites immediately landed and perched on some tall liquid amber trees.
Rich Cimino
Pleasanton
Las Trampas Regional Wilderness near San Ramon
Sun, 11 Jul 2004 22:51:23 -0700
From: Larry Tunstall
I am forwarding this message to the list for Michelle Brodie:
Sun, 11 Jul 2004 22:07:11 -0700 (PDT)
Hello Birders,
On July 10, I went for a hike in Las Trampas Regional Wilderness near San Ramon. I saw half a dozen Grasshopper Sparrows on the Rocky Ridge Trail and then two Rufous-crowned Sparrows on the Sycamore Trail. The complete list of birds as saw was as follows:
- Turkey Vulture
- Red-Shouldered Hawk
- California Quail
- Mourning Dove
- White-throated Swift
- Anna's Hummingbird
- Northern Flicker
- Western Wood-Pewee
- Pacific-slope Flycatcher
- Ash-throated Flycatcher
- Horned Lark, Violet-green Swallow
- Cliff Swallow
- Steller's Jay
- Western Scrub-Jay
- Chestnut-backed Chickadee
- Oak Titmouse
- House Wren
- Blue-gray Gnatcatcher
- Western Bluebird
- Wrentit
- Hutton's Vireo
- Lazuli Bunting
- Spotted Towhee
- California Towhee
- Rufous-crowned Sparrow
- Lark Sparrow
- Grasshopper Sparrow
- Song Sparrow
- Dark-eyed Junco
- Western Meadowlark
- Brewer's Blackbird
- Purple Finch
- House Finch
- Lesser Goldfinch
Michelle Brodie
Posted to EBB by Larry Tunstall
Probable Greater White-fronted Goose on Emeryville mudflats
Mon, 12 Jul 2004 11:20:46 -0700 (PDT)
From: Peter Diegutis
Good Morning
Is this another Emeryville notable, or are my eyes getting worse? As I sped along the on-ramp to the Bay Bridge this morning, I can (almost) swear I saw a lone Greater White-Fronted Goose standing in a little estuary where a drainage culvert outlets to the bay.
There are certainly Canada Geese who live in the area, but I feel reasonably confident that this wasn't one of them. I must take this short section a little slower tomorrow!
Have a nice day.
Cheers
Peter
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White geese at Berkeley Aquatic Park
Mon, 12 Jul 2004 13:05:11 -0700 (PDT)
From: Alan Howe
I was down at Berkeley Aquatic Park yesterday afternoon (and finally saw the Pied-billed Grebe nest) and noticed some white geese among the Canada Geese there. I didn't note a lot of details and thought they might be Snow Geese; they certainly didn't look like domestics. Are Greater White-fronted Geese all white? (I don't have a field guide nearby right now. Guess I'll have to look it up.) I did find it interesting that 2 of the white geese were swimming along in line with some Canada Geese.
Take care,
Alan
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Identifying geese
Mon, 12 Jul 2004 23:43:27 -0700
From: Larry Tunstall
Alan Howe asked if Greater White-fronted Geese are all white. Just for the record, Greater White-fronted Geese are not very white at all. The "white front" is a little white area adjoining the base of the bill. See
http://www.saltgrassflats.com/birds/white_fronted_goose.html
Ross' Goose and Snow Goose are wild geese that are almost all white, but with black wingtips. The all-white geese that are quite common around this area, often hanging out with Canada Geese (as do Greater White-fronted Geese and most any other goose around), are domestic breeds.
Furthermore, there are domestic geese that look very similar to the Greater White-fronted Goose, and they also are common in this area. And then there are all kinds of hybrids!
This page has some useful tips and pictures about such things:
http://birds.cornell.edu/crows/domgeese.htm
Best wishes, Larry
Larry Tunstall
El Cerrito CA
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