Mexican Duck ID question (Pleasant View Marsh, Boulder Cty)

[Thomas Heinrich]

After several misses, I finally was in the right place at the right time to see the Mexican Duck that's been in residence in the Pleasant View/Sale Lake area in Boulder apparently for quite some time.  I've got a question about the purity of this particular individual stemming from the upcurling tail feathers as shown in the photo below.  Does this character mean that it is not a pure Mexican Duck, but rather a hybrid to some degree?  I read Jack Bushong's excellent piece on Mexican Ducks on the ABA website which mentions this very issue.

Thanks for any input,

Thomas

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Thomas Heinrich
Boulder, CO
TEHei...@gmail.com
www.pbase.com/birdercellist

[Caleb A]

Hi Thomas!

I'll start with a disclaimer: I'm not an expert on Mexican Ducks.

The reason I'm putting in a word is because I remember learning from a waterfowl presentation that Mallard ducks (both sexes) and Northern Shovelers are the only dabbling ducks that have white tail feathers. Since Mexican Duck is not either Mallard or Northern Shoveler, a pure Mexican Duck should not have white tail feathers. I do agree that this bird looks to have Mexican genes. The bill and head look consistent with Mexican, but the tail looks more Mallard to me. I'd suggest this is a Mexican x Mallard, although I'm eagerly awaiting the experts to weigh in on this one. Great photo!

The birds are happy, and so am I

~Caleb Alons, Larimer County

[David Tønnessen]

Thomas, Caleb,

Yes, as pointed out in a Facebook discussion earlier today, the bird appears to be a hybrid (albeit more Mexican looking than your average F1). The black uppertail coverts, as well as whitish rectrices and curling are indicative of Mallard genes, and in some photos the tertials appear gray-tinged as well (another Mallard trait). Pure Mexican Ducks also typically pop out as pretty dark, which this bird didn't to my eye in comparison to female Mallards it was photographed with (albeit still slightly darker). Still, a very cool bird with great discussion to be had.

Cheers,

David Tonnessen

Colorado Springs, CO

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David Andreas Tonnessen

Student @ CU Boulder

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[Thomas Heinrich]

Thank you David and Caleb for your replies to the question of Mallard/Mexican/hybrid ID!  I appreciate your insight, observations, and the discussion of details to note when considering IDs of this sort.   I've had a couple other replies off-list both in support of Mallard x Mexican hybrid as well.  They mentioned the curled upper tail coverts and light tail feathers being indicative of hybrids with Mallards, both in Mexican and Mottled Ducks. 

I have photos of another likely Mexican x Mallard somewhere in my photo archives taken several years ago that I'm curious to have another look at now.  

Thanks again!

Thomas

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