First, as a brand new birder, welcome to this great pastime, Karen! And thanks for your good question.
Some would label those funky birds "Mallard (Domestic type)" which is a checkbox on the eBIrd list.
My personal name for them is "ducks of uncertain heritage."
In the Sibley field guide and some others, there is a drawing of similar birds in the "domestic duck" section.
Keep on birding'! Joe Roller, Denver
To paraphrase an old saw - "Its a wise duckling who knows who his father is."
On Wed, Feb 7, 2018 at 8:23 AM, Karen Strong <kstrong1109...> wrote:
> Please forgive my ignorance - I'm a brand new birder & have only been > observing for a little over a month. > > I saw these ducks yesterday (2/6/18) in the pond in Prospect Park, Wheat > Ridge. My best guess is that they are Mallard-Northern Shoveler hybrids. > They resemble male Mallards, in that they have green heads, yellow bills, > and those curly "butt" feathers (I'm sure there's a more proper term for > those). But they were significantly larger than a Mallard they paddled by > - they were about the size of a cackling goose that was also nearby. And > then there are those white chest markings. Northern Shovelers have white > chests, and the front duck's bill definitely looks Shoveler-like in shape. > But Northern Shovelers are even smaller than Mallards. Could the offspring > of a Mallard-N. Shoveler mating be larger than either species? Do these > species even "commingle"? > > > <https://lh3.googleusercontent.com/-NiB2TQd-V00/WnsY4grz4cI/AAAAAAAACHw/rt1YahlKDXULyHpRseQAIOS-c7cE2ObugCLcBGAs/s1600/2.6.18%2Bodd%2Bducks.jpg> > > Thanks to anyone who can enlighten me! > > Karen Strong > Conifer, CO > > -- > 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+<unsubscribe...> > To post to this group, send email to <cobirds...> > To view this discussion on the web visit https://groups.google.com/d/ > msgid/cobirds/<0bd5c6a4-726a-4bdf-b3e8-46ba38894bc8...> > <https://groups.google.com/d/msgid/cobirds/<0bd5c6a4-726a-4bdf-b3e8-46ba38894bc8...>?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. >