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      Whatbird Forums Rules   01/08/17

      'Help Me Identify a Bird' rules: When posting a new thread, please: 1. Read the FAQ and forum rules before posting 2. Include the location in your Post when seeking ID 3. Include the date of the sighting 4. Provide a photo or detailed description of the bird Forum rules: By posting in the WhatBird forums you agree to the following board rules: 1. You will be tolerant and respectful of your fellow members 2. You will not spam 3. You will not post sexually explicit, vulgar or racist material 4. You will not advertise or sell products 5. You will not discuss illegal activities 6. You will keep topics of religion and politics to a bare minimum 7. You will not take advantage of chat to break any of the above rules. 8. Members will not discuss homosexuality nor make any comments about others' sexuality. Breaking any of these rules may result in a suspension or a permanent ban from the forums!! Furthermore, anyone who causes continuous dissent and disarray in the forums will be banned as seen fit by the forum moderators under the pretense of "trolling." Gallery photos: Regarding photos in the Whatbird gallery, please keep in mind that the copyright belongs to the person who took the photo. So please do not use any of the Gallery photos without requesting permission from the photographer. Forum Photos: If you use photos other than your own, please place a link to the referenced photo and do not post other photographer's work directly.
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      Found a baby bird or a sick or injured bird?   07/11/17

      Here is a short article with advice for what to do if you find a baby bird or one that appears to be sick or injured. Bird rescue article Please feel free to post here if you have questions or need more help.
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Colorado Owl

Mallard/Mexican

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Since it's in Colorado, I'd happily call that a Mexican-Northern intergrade.  It's not a pure Mexican because of the white borders of the speculum and maybe other things, though.

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9 minutes ago, Jerry Friedman said:

Since it's in Colorado, I'd happily call that a Mexican-Northern intergrade.  It's not a pure Mexican because of the white borders of the speculum and maybe other things, though.

The Mexican Duck does have white borders on the speculum and I believe it's speculum and borders are identical to that of a female Mallard. It's out of the area where you would expect to see A Mexican Duck (Especially this time a year) and with the extensive interbreeding with Mallards, it could have some Mallard blood in it, but it looks like a male (yellow bill) Mexican duck. Ducks pair up in the wintertime and the male follows the female to her nesting ground. Perhaps he paired with a hen Mallard last winter and followed her North.

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@JacksonBounds: There seems to be some disagreement on the wing pattern of the Mexican Duck.  Hubbard (1977) said the "bars" on its wings are "narrower, anterior one often suffused with dusky".  Scott and Reynolds (1984) were more definite: "The white band in front of the speculum is missing in the Mexican Duck, contrary to the belief of Bellrose (1976) and many previous authors."  Both papers say that the Mexican's speculum has a greenish sheen, unlike the purplish sheen of the Northern.  I'll let people with better color vision than me comment on the color of this bird's speculum.

Edit: Also, this bird's tail looks to me more like the "grayish brown" that Hubbard says intergrades have than the "rich brown... outermost feathers largely dark" that he says pure Mexicans have.

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One problem with subspecies ID in most cases where the two forms intergrade, is that the decision as to what's a "pure" bird and what's an "intergrade" is purely arbitrary. There aren't discrete populations to work with, rather there's two that blend into each other, and the degree of blending that's acceptable varies with the author.

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2 hours ago, psweet said:

One problem with subspecies ID in most cases where the two forms intergrade, is that the decision as to what's a "pure" bird and what's an "intergrade" is purely arbitrary. There aren't discrete populations to work with, rather there's two that blend into each other, and the degree of blending that's acceptable varies with the author.

On that subject, Hubbard said the tail as well as the wings is more variable than other characteristics in ducks of central Mexico, though most birds there still have the "pure" characteristics.  That's a point in favor of calling this bird Mexican.

However, no matter where authors draw the line, all agree that Mallard intergrades are far more common in the U.S. than pure diazi, so I'd call anything north of the border an intergrade unless it has 100% diazi characteristics.

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I agree that where to draw the line between pure Mexican and intergrade is clearly in the eyes of the author. I did not know there was so much disagreement among the "experts" or that some considered the pure Mexican to have no white border on the front of the speculum, thanks for the information. 

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