Mexican Duck-Fossil Creek Reservoir (Swede Lake side)-Larimer

[Josh Bruening]

All,

There is duck that looks quite good for a full-on Mexican Duck in the Southeast arm of Fossil Creek Reservoir a.k.a Swede Lake.  I am reporting it as such at the present time. The bird has been present since at least Friday.  Several of us have gotten pics of the bird ranging from decent to not so decent.  But there is some question as to whether this bird is pure Mexican or could possibly be a Mallard x American Black Duck.  I have attached my ebird checklist here for people to review the photos I have.  This bird show absolutely no white on the tail or undertail coverts.  No curled tail feathers.  There are white margins around the speculum (eliminating pure American Black Duck).  No black spot at gape to eliminate Mottled.   The short views I got of the speculum showed turquoisy-blue to dark blue. The color depended on the angle of the light and I at best saw it for a couple seconds three times.  If anyone out there fancies themselves a Mexican Duck or Mallard x American Black Duck expert, please take a look.  This bird does not remind me of the Black Ducks I grew up watching in PA.  But, the only crosses I've seen of Mallard/ABDUs the birds were showing much green on their heads.  This bird may be a back-cross if it is a hybrid.  It also does not appear to be a Mallard x Mexican either.  Thanks in advance for the help.  

https://ebird.org/checklist/S75697655

Bird is the word y'all!

Josh Bruening

Fort Collins