Evelyn,
   Your dark duck may be a Duclair Duck, a common breed of Mallard that is darker than the Swedish Blue which looks similar. It is frequently found where domestic Mallards hang out. There were two today on Centennial Lake. For more than you ever wanted to know about Mallard breeds check out:  www.feathersite.com/poultry/ducks/brkducks.html
--
Bob Ringler
Eldersburg MD


---- Evelyn Ralston <> wrote: 
> My friend Jennifer Kawar and I were at Hains Point DC, today 10-11:30  
> am. The Brant was on the grass beyond the sculpture, together with  
> several gulls.
> 
> A number of ducks and gulls came to the edge of the water, on the  
> Washington channel, to be fed by a woman and her young daughter. The  
> ducks were Mallards, males and females, except (?) for one very dark  
> duck, with a white patch on the breast, which we could not identify.  
> A melanistic Mallard? I have posted a photo of the Brant and photos  
> of this duck at http://www.pbase.com/erforthebirds
> (click on the brant thumbnail to open the gallery). I look forward to  
> help with its identification.
> 
> In the high grasses and small trees between the restrooms and the  
> golf course there were numerous birds including house finches, a  
> junco, a fox sparrow, a mockingbird, a red-bellied woodpecker. A bald  
> eagle stopped briefly on one of the large trees.
> 
> 
> Evelyn Ralston
> Bethesda, Md
>