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Early ELEGANT TERNS 3/20/23
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This morning birding with Logan Kahle, after seeing the continuing Vesper Sparrow, we scoped the channel off Crissy Field and were slightly surprised to see at least (3) ELEGANT Terns plunge feeding among the gulls against the back drop of Fort Baker and Angel Island.
Elegant Terns arriving in spring has been a regular occurrence in the Bay Area since 2015 when they showed up in April at Bolinas Lagoon. But today’s sighting is 11 days before the previous early arrival date for SF (3/31/22) and 13 days earlier than last year (4/2/22) Apparently they were photographed a couple of days ago on the Alameda bayside as well. Dominik Mosur San Francisco |
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Correction:
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Last year elegant terns were first noted from SF by BRIAN FITCH on 3/22/22. My apologies for the omission, I stupidly relied on a quick scan of eBird records only before making my post. Should’ve done more thorough research. DM SF On Mar 21, 2023, at 06:59, Brian Fitch <fogeggs@...> wrote:
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Brian Fitch
This still represents a surprisingly early return for the species, especially considering the extremely cold and stormy conditions. Brian Fitch On Tue, Mar 21, 2023 at 7:06 AM Dominik Mosur <dominikmosur@...> wrote:
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rfs_berkeley
I wonder if March arriving Elegants might be a sign of nesting failure. From Birds of the World: "Small numbers begin arriving in California in late May, increasing through Jun; peak numbers Jul-Sep (Unitt 1984b, Small 1994). Numbers decline by early Nov (Small 1994) as birds migrate south to wintering grounds in Guatemala south to central Chile..." Normal post breeding migrants should be two months off. Even southern California breeders are just getting started.
But then:
"......probably does not breed until at least third summer. Birds 1 yr old (second summer) seen in colonies observing copulations, but not actually breeding (Schaffner 1982)."
Maybe early ones are not mature enough to breed.
Rusty Scalf
Berkeley
On 2023-03-21 07:06, Dominik Mosur wrote:
Correction: |
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Peter Pyle
Hi Rusty -
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I think instead that the early arrivers are full adults. In Bolinas Lagoon, we have been seeing increasing numbers in March-May from the late 1980s until now, so the information in BoW is out of date. My earliest there were of a pair of breeding adults on March 20, 2015: https://ebird.org/checklist/S22441152 At first we thought these were simple spring overshoots but when we started seeing 100+ in the past few years it seems there was something more to it. They began breeding in the South Bay at Don Edwards NWR a few years ago and so instead it seems their breeding range is continuing to expand north. This has been going on in California since the 1970s, as documented in the BoW account (under Demography and Populations) and by Collins et al. in 1991: https://sora.unm.edu/sites/default/files/journals/nab/v045n03/p00393-p00395.pdf They also respond positively to the abundance of anchovy off our coast, which has been high in recent years during this cold phase of the Pacific Decadal Oscillation (which may should to warm phase in the next year or so). So their increasing early presence in SF is likely a combination of expanding populations anyway (also....climate change...) and high numbers of anchovy in recent years. Cheers, Peter At 11:16 AM 3/21/2023, rfs_berkeley wrote:
I wonder if March arriving Elegants might be a sign of nesting failure. |
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Jim Chiropolos
I personally believe the “early” arrival of Elegant Terns is due to the colony at Alameda island that has successfully bred there the last two years.
Previous years there were no nesting of any significant numbers of the e terns. That has been different the last two years. I cannot find the statistics for last years breeding colony, but I believe it was a lot of e terns. The terns breed on the Alameda island wildlife preserve which has restricted access. Jim Chiropolos Orinda |
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Ryan Phillips
Jim is on it. Don't forget they are now breeders in the Bay Area. There is a "significant" number of nesting Elegants at Ravenswood in Don Edwards NWR. We do not know if they are resident, so maybe these birds are here through winter or spend time in Southern California and return early to the Bay Area than our usual migrants. On Tue, Mar 21, 2023, 2:30 PM Jim Chiropolos <jnc@...> wrote: I personally believe the “early” arrival of Elegant Terns is due to the colony at Alameda island that has successfully bred there the last two years. |
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Totally agree that these “early” terns are almost certainly local breeders arriving right on time as opposed to failed nesters from somewhere else. While watching them fishing in the channel yesterday Logan mentioned this is right about the time SoCal breeders show up at colony sites. DM On Mar 21, 2023, at 17:09, Ryan Phillips <norcalbirding@...> wrote:
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Alvaro Jaramillo
All, While a few linger in California in winter, the major wintering area for Elegant Terns is Peru down to central Chile. This is where you can see hundreds to thousands in wintering flocks, often mixed in with masses of Franklin’s Gulls. They are generally much more migratory than Caspian Terns which winter in Mexico – Central America mainly, but surprisingly Elegants hang in later on in the fall than Caspians which are notoriously early southbound migrants. Elegants are much more specialized on sardines/anchovy so I assume their winter distribution does shift a bunch depending on water temperature and productivity (positive or negative ENSO). They will also forage much farther offshore than Caspians, which are very coastal, or prefer estuarine systems. At this time of year there are NO Elegants nesting anywhere, so they can’t be failed breeders. The move north has been parallel to the Black Skimmer, but has lagged. I assume that there will many initial failed years, until a colony big enough establishes and then their breeding success will increase substantially.
Alvaro Jaramillo
From: SFBirds@groups.io <SFBirds@groups.io> On Behalf Of Ryan Phillips
Sent: Tuesday, March 21, 2023 5:01 PM To: Jim Chiropolos <jnc@...> Cc: SFBirds@groups.io Subject: Re: [SFBirds] Early ELEGANT TERNS 3/20/23
Jim is on it. Don't forget they are now breeders in the Bay Area. There is a "significant" number of nesting Elegants at Ravenswood in Don Edwards NWR. We do not know if they are resident, so maybe these birds are here through winter or spend time in Southern California and return early to the Bay Area than our usual migrants.
On Tue, Mar 21, 2023, 2:30 PM Jim Chiropolos <jnc@...> wrote:
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Megan Jankowski
Hi everyone, across the bay on Saturday I led a GGAS walk at Middle Harbor Shoreline. There were 8 Elegant Terns. We saw a pair exhibiting display behaviors, ie offering a fish and extending their necks up. I later saw one fly in the direction of Alameda with a fish.
Megan Jankowski |
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