Date: 6/18/25 2:32 pm From: Wayne Hoffman <whoffman...> Subject: Re: [BIRDWG01] Booby ID
Hi -
I do not contest your suggestion the features you describe tend to favor Brown Booby, but I am not sure that "the location strongly favors Brown." Many years ago I chased a Blue-footed Booby in central Texas, and I doubt it got there via the gulf. In addition, I think there is a pattern of at least occasional vagrancy of seabirds from the Sea of Cortez into the southwest. Oklahoma has a Great Frigatebird record, Blue-footed Booby vagrancy has reached Arizona, Nevada, Utah, and New Mexico, as well as Texas.
Wayne Hoffman
----- Original Message -----
From: "David Sibley" <sibleyguides...>
To: "BIRDWG01" <BIRDWG01...>
Sent: Wednesday, June 18, 2025 3:59:23 PM
Subject: Re: [BIRDWG01] Booby ID
I did a lot of work on this question a year ago, starting from the excellent work by Eric VanderWerf and looking at lots of photos. This bird is a subadult, and I could not find any reliable way of separating Brown and Cocos Booby at that age. The yellow facial skin and pinkish bill seem more typical of Atlantic (but can be matched by some Cocos), and the impression that the neck is darker than the back favors Atlantic. Other features like forehead color and underwing pattern can be helpful on adults but not on subadults.
As Paul says the location strongly favors Brown. All of the identifiable photos (adults) that I saw from eastern North America are Brown, but there is one Cocos record from the Caribbean off Panama.
Best,
David
<sibleyguides...>
www.sibleyguides.com
> On Jun 18, 2025, at 2:25 PM, Paul Lehman <00000ae015dd4920-dmarc-request...> wrote:
>
> Slide presentation from wfo meeting in San Diego last October. Bill color potential differences would suggest Colorado bird may be a Cocos, given all the brownish in the bill, which seems surprising in Southeast Colorado where one would think it's a bird up from the Gulf of Mexico and therefore a Brown.
> Paul Lehman
> Sent from AOL on Android
>
> Archives: https://listserv.ksu.edu/birdwg01.html
