Re: [cobirds] variation in juvenile Cliff Swallows

Great discussion . . . one fairly reliable field mark that hasn't been addressed (I think) in this thread . . .

Cave Swallow's auriculars are LIGHT and Cliff Swallow's auriculars are dark . . . this gives the species a very different look/feel/gizz:  "capped" in Cave and "helmeted" in Cliff.  Youngsters can look very weird, however, I'd concede. 

sebastianpatti@hotmail.com
Sebastian T. Patti
770 S. Grand Avenue

Unit 3088

Los Angeles, CA 90017 
CELL: 773/304-7488

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From: cobirds@googlegroups.com <cobirds@googlegroups.com> on behalf of tedfl...@gmail.com <tedfloyd73@gmail.com>
Sent: Saturday, August 22, 2020 8:46 AM
To: Colorado Birds <cobirds@googlegroups.com>
Subject: [cobirds] variation in juvenile Cliff Swallows

 

Hey, all.

Leaving aside for now the question of HOW juvenile cliff swallows are variable, I thought it would be cool to ask WHY juvenile cliff swallows are variable. Ask, and it will be given you:

https://academic.oup.com/auk/article/131/2/121/5148982

The preceding is a link to a 2014 paper in the journal formerly known as The Auk, by ornithologists Allison E. Johnson and Steven Freedberg ("Variable facial plumage in juvenile cliff swallows: A potential offspring recognition cue?"). The following is an oversimplification of Johnson and Freedberg's discovery, but in essence: Every juvenile cliff swallow is different! Human parents supposedly can recognize their own children's cries--which is total balderdash. But swallow parents apparently can distinguish their children from all the hundreds, and occasionally even thousands, of children out there. It's all based on the unique "finger print" of white and black on the faces of juvenile cliff swallows.

Here's a "typical" juvenile cliff swallow (except there is no such thing as "typical"):

https://macaulaylibrary.org/asset/107168241

I put this picture up at a bird talk a little while ago, and nobody knew what it was. I'm not talking cliff vs. cave. I'm saying, people were talking American robin vs. white-throated sparrow. More votes for the former than the latter, but more votes for either than for any swallow species! We all know it's a cliff swallow because we're having a conversation about cliff swallows ("don't think about an elephant!"), that's all.

Thanks to David Tønnessen and to his interlocutors for the edifying learning experience.

Ted Floyd
smoky Lafayette, Boulder County

On Friday, August 21, 2020 at 12:54:10 PM UTC-6 rori...@earthlink.net wrote:

What a wonderful, illuminating discussion we are having on Cobirds

David Tonnessen alludes in his recent posts in the difficulty in separating juvenile Cliff swallows from juvenile  and perhaps adult Cave Swallow. 

Tony's post, in part, concurs with that premise but suggest that phase of juvenile plumage may not be that prevalent?

In the Sibley Guide the notation adjacent to the depiction of the juvenile Cliff Swallow (Jun-Dec) "juveniles extremely variable…"

So what do we do about this dilemma in Colorado. Could we just say that any well documented record of a Cave Swallow before June would be more viable than any juvenile record of a Cave Swallow discovered after June which would to have to have an exceptional level of documentation. Would even photographic evidence be satisfactory or would it take just  specimen evidence?

Bob Righter

Denver CO 

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