Hi all,
Thought I’d throw in my two cents on this bird given that it seems to have become a popular topic of discussion. Thank you to Sally Waterhouse for bringing this bird to Cobirds so it can reach a broader audience. I presume that the bird I documented on December 29 is the same bird that has been subsequently seen by Sally Waterhouse and Greg Mihalik. In the field, this bird looked like a classic male Mexican Duck (MEDU), and I maintain that identification after reviewing photos by others. This bird demonstrates all of the characteristics of a pure male MEDU, including dark body plumage, strong contrast between the breast and neck, fine gray streaking on the face, internal markings on the body feathers, and a dark brown tail and undertail coverts. The speculum is also fairly typical of MEDU (and is generally not the most reliable field mark for separating MEDU from MALL anyways as there is some variability/overlap). When I observed this bird in flight, its speculum was bright turquoise, but in this photo (ML406400291 Mallard/Mexican Duck Macaulay Library <https://macaulaylibrary.org/asset/406400291>), it appears more purplish-blue. That is to be expected as the apparent color of the speculum can change drastically depending on the light conditions. Another possible point of contention is that in this photo (ML405633971 Mallard/Mexican Duck Macaulay Library <https://macaulaylibrary.org/asset/405633971>), the edges of the tail appear rather pale. However, this is sometimes true of MEDU when viewed from the side. More important is that, when the tail is fanned out, as seen in this photo (ML406400291 Mallard/Mexican Duck Macaulay Library <https://macaulaylibrary.org/asset/406400291>), it reveals a classic MEDU tail pattern with very little if any white. While it is impossible to say without genetic analysis that this bird’s genome doesn’t have a trace of MALL influence, I would expect a MALL x MEDU to have some combination of paler body plumage, less contrast between the breast and neck, green in the head, white in the tail and undertail coverts, black uppertail coverts, and curved tail feathers. As for the possibility that this bird is a MEDU x MODU, I would expect such a hybrid combination to have a more prominent black gape spot, as male MEDU often exhibit a small amount of black/dusky near the gape as seen in these birds: ML85267311 Mexican Duck Macaulay Library <https://macaulaylibrary.org/asset/85267311>, ML402523711 Mexican Duck Macaulay Library <https://macaulaylibrary.org/asset/402523711>, ML404334831 Mexican Duck Macaulay Library <https://macaulaylibrary.org/asset/404334831>. Also, a MEDU x MODU hybrid would likely have a paler, buffier face, whereas this bird has a colder, dirtier face due to numerous fine dark streaks. I would also expect to see thinner white borders to the trailing and leading edge of the speculum if this were a MEDU x MODU. Thanks to all who read this lengthy response! It’s always fun to try and pin down the ID of these difficult birds. Regards, Jack Bushong Louisville, CO/Hanover, NH On Monday, January 17, 2022 at 12:14:32 PM UTC-5 Nick Komar wrote: > I will go out on a limb and suggest that this is a candidate for Mexican x > Mottled based on the appearance of typical male Mexican Duck except for > three traits inherited from Mottled Duck: moderate black gape spot, purple > tinge to blue speculum, and buff patch on throat. Are these all within the > range of variation for Mexican Duck - possibly (I don’t know). I suggest > posting to the bird hybrids facebook page for more opinions. > > Nick Komar > Fort Collins CO > > On Jan 16, 2022, at 1:05 PM, Sally Waterhouse <smwa...@owu.edu> wrote: > > New photo showing speculum of same bird in question > https://ebird.org/checklist/S100849831 To me the speculum looks like > typical Mallard. > > Sally Waterhouse > Nathrop, CO > > On Sunday, January 16, 2022 at 8:19:57 AM UTC-7 Sally Waterhouse wrote: > >> Looking for some thoughts on this. The duck has been observed by several >> birders in Chaffee County just west of the 163 pond hotspot in a small pond >> area. Whether this is the same duck reported as a Mexican on Dec. 29 by >> Jack Bushong on 163 pond is unknown. After perusing many discussions about >> this "complex" I'm curious as to what people may think about this >> individual. See photos on my ebird checklist >> https://ebird.org/checklist/S100712744 and also on Greg Mihalik's >> checklist https://ebird.org/checklist/S100667677. Looking more closely >> at photos I realized that there is also a dark gape spot just to add to the >> question. So far, no speculum photos. >> Sally Waterhouse >> Nathrop, Chaffee County >> > -- > -- > You received this message because you are subscribed to the Google > Groups "Colorado Birds" group. > To post to this group, send email to cob...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/cobirds?hl=en?hl=en > * All posts should be signed with the poster's full name and city. 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Include bird species and location in the subject line when appropriate * Join Colorado Field Ornithologists https://cobirds.org/CFO/Membership/ --- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To unsubscribe from this group and stop receiving emails from it, send an email to cobirds+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/b5c2b86b-b74d-4f00-bbe3-1a8ad744da6dn%40googlegroups.com.
