On Jun 17, 2019, at 11:58 AM, Alvaro Jaramillo <chucao@...> wrote:

John
Before the hybrid hypothesis catches too much fire. I am convinced that these birds are dark billed Elegants. Dark on the bill in Elegant Terns is common, the rarity in these cases is the extent. They can be nearly all black, like this one I saw in 2013 here in Half Moon Bay:

https://www.flickr.com/photos/alvarojaramillo/9442203562/in/photolist-XsSNif-wSAYus-wnvJR7-fCuq4m-fo8utM-fonLa9-fdmzyT-fdmziP-fdmzr8-dUozc2-d75zfy-d75yGs-d75BBs-cRqARh-agA1zx-9VJghg

The hybrids that have been identified on Isla Rasa, Baja California to my eye are again just Elegants with dark on the bill. There are color photos in the paper:
http://www.marineornithology.org/PDF/40_1/40_1_25-29.pdf
They spot various birds with dark on the bill, and assume they are all backcrosses from some original hybridization some time back. But they did not see any Sandwich (Cabot's) Tern while they performed their study. Again, I do not think they were considering that these were merely a variation in Elegant Tern. The bill shapes of these birds are classic Elegant, no sign of the shorter and straighter bill of Sandwich.
So in summary, I do not think the current bird is a hybrid. I think it is a dark billed Elegant Tern.
Alvaro

Alvaro Jaramillo
alvaro@...
www.alvarosadventures.com

-----Original Message-----
From: CALBIRDS@groups.io <CALBIRDS@groups.io> On Behalf Of John Sterling
Sent: Sunday, June 16, 2019 8:38 PM
To: jtnikon@...
Cc: EBB-Sightings@groups.io; calbirds@groups.io
Subject: Re: [CALBIRDS] [EBB-Sightings] Sandwich Tern (6/16/2019) - photos

I received a text message from an expert who I totally trust who saw the bird and determined that it was a hybrid. I’ll let him comment but just wanted to get the word out. Several records in recent years in California have proven to be hybrids. I’m in China so I haven’t seen the bird.
John Sterling
530 908-3836
26 Palm Ave
Woodland, CA 95695

On Jun 17, 2019, at 10:26 AM, Jerry Ting via Groups.Io <jtnikon=yahoo.com@groups.io> wrote:

As Bob Toleno stated in his previous posts, the Sandwich Tern reported by Bob Richmond and John Luther continued to be seen in the tern colony pond in Hayward Marsh that can be seen (using a scope) from the Least Tern sign and spent most of the time preening on the south side of the island (37.630029, -122.144366) on northeast of the Least Tern island. I have included 2 distant shots of the bird in my eBird report in which you can see the yellowish tip on the dark bill and dark legs.

https://ebird.org/view/checklist/S57431258

Happy Birding,
Jerry Ting
Fremont

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