Vireo reports


 

With all due respect to those posting: Regarding these reports of multiple Cassin’s Vireos from multiple locations , please note that over many decades now a typical arrival
Date for Cassins Vireo in SF is around the first days of April. A few exceptionally early birds have been noted by the third week of March.

Cassin’s vireos winter in Mexico. There’s typically a pulse of migrants noted in SoCal before we start seeing them up here.

Good birding,

Dominik


On Mar 1, 2021, at 10:40, Ken Moy <ken.moy62@...> wrote:


Hi all, 2 Cassin's vireos (1 seen, 2 heard) on Oak Woodlands on the wooden box steps leading to Stanyan and Fulton.

Good birding.

Ken Moy


 

John,

A Cassin’s vireo at this time of year in SF would almost certainly be an overwintering bird.

While we have a couple of winter records over the years, this seems to me a very normal occurrence of one inexperienced observers making an erroneous report that then convinces other inexperienced observers that’s it’s not time to start reporting the species.
This happens every year and is part of the learning process. No harm done.


On Mar 1, 2021, at 19:20, John Facchini <john.facchini@...> wrote:


Hello Dominik,

I followed up on Ken's post and saw a vireo that was mostly gray and had clear (but not very bold) white spectacles - the bill eliminated kinglets and warblers.  I only saw one and didn't hear any vocalizations.  I was focused on making sure I got a clear look at the spectacles and didn't get much of a view of the underside of the bird.  I was comfortable with a cassin's vireo ID.  Your post makes this seem like either an exceptional sighting or a mistaken ID.  I don't mean to ruffle any feathers and am ok removing my sighting from ebird if you would like me to. 

Regards, 
John Facchini

On Mon, Mar 1, 2021 at 2:10 PM Dominik Mosur <dominikmosur@...> wrote:
With all due respect to those posting: Regarding these reports of multiple Cassin’s Vireos from multiple locations , please note that over many decades now a typical arrival
Date for Cassins Vireo in SF is around the first days of April. A few exceptionally early birds have been noted by the third week of March.

Cassin’s vireos winter in Mexico. There’s typically a pulse of migrants noted in SoCal before we start seeing them up here.

Good birding,

Dominik


On Mar 1, 2021, at 10:40, Ken Moy <ken.moy62@...> wrote:


Hi all, 2 Cassin's vireos (1 seen, 2 heard) on Oak Woodlands on the wooden box steps leading to Stanyan and Fulton.

Good birding.

Ken Moy


Adam Winer
 

As Dominik notes, there are exceedingly few records of any members of the "Solitary" Vireo complex at this time of year.  The image attached below is the eBird barcharts for the combined Bay Area counties - you'd conclude from this data that Plumbeous Vireo is equally likely if not more so than Cassin's, but none are likely at all.  (No, I'm not suggesting people saw Plumbeous.)  And none of those January/February/early March records in eBird are from San Francisco.  I can't say that any one of these records is certainly erroneous, but I can say that the notion that *all* of these reports are correct strains credulity.

At any rate, the basic rule applies:  these would be exceptional records, and therefore they need good documentation.  Even if one was seen well enough to confidently identify it as a "Solitary" Vireo, you'd still need careful elimination of both Blue-headed and Plumbeous Vireos.  And note that at this time of year, these would all typically be on the dull side, making identification even more challenging.

image.png

-- Adam Winer

On Mon, Mar 1, 2021 at 8:22 PM Dominik Mosur <dominikmosur@...> wrote:
John,

A Cassin’s vireo at this time of year in SF would almost certainly be an overwintering bird.

While we have a couple of winter records over the years, this seems to me a very normal occurrence of one inexperienced observers making an erroneous report that then convinces other inexperienced observers that’s it’s not time to start reporting the species.
This happens every year and is part of the learning process. No harm done.


On Mar 1, 2021, at 19:20, John Facchini <john.facchini@...> wrote:


Hello Dominik,

I followed up on Ken's post and saw a vireo that was mostly gray and had clear (but not very bold) white spectacles - the bill eliminated kinglets and warblers.  I only saw one and didn't hear any vocalizations.  I was focused on making sure I got a clear look at the spectacles and didn't get much of a view of the underside of the bird.  I was comfortable with a cassin's vireo ID.  Your post makes this seem like either an exceptional sighting or a mistaken ID.  I don't mean to ruffle any feathers and am ok removing my sighting from ebird if you would like me to. 

Regards, 
John Facchini

On Mon, Mar 1, 2021 at 2:10 PM Dominik Mosur <dominikmosur@...> wrote:
With all due respect to those posting: Regarding these reports of multiple Cassin’s Vireos from multiple locations , please note that over many decades now a typical arrival
Date for Cassins Vireo in SF is around the first days of April. A few exceptionally early birds have been noted by the third week of March.

Cassin’s vireos winter in Mexico. There’s typically a pulse of migrants noted in SoCal before we start seeing them up here.

Good birding,

Dominik


On Mar 1, 2021, at 10:40, Ken Moy <ken.moy62@...> wrote:


Hi all, 2 Cassin's vireos (1 seen, 2 heard) on Oak Woodlands on the wooden box steps leading to Stanyan and Fulton.

Good birding.

Ken Moy