What kind of duck is this?

On my walk home from work I regularly pass a large gathering of ducks, geese and swans. Over the past couple of days I noticed a few of the Male ducks are much larger and seem to have much darker heads than the others (not the best photo, but best I could muster with low light on a cycle path). The two in the background are examples of these, would anyone be able to help identify these? They stand in a much more upright stance and have considerably longer torsos. I tried to search for them on google but was unable to find anything with the same colourings and shape. Many thanks! 

Update: I was able to find the two ducks again and have some slightly better comparison photos(posted above original photo), I could spot them from a distance of about 30 feet as they are that much larger than the other ~20 mallards. They seem to lack the white neck ring all of the other male ducks have and the elongated, swollen shape of their backsides is completely different.

  • Hi SquidRings, all the 4 ducks are Mallards; 3 male drakes on the right, the female on the left. The other drakes only look larger because sometimes they are standing more upright, stretching their necks up and not in the more relaxed position as the drake below them. They will be keeping close company with females as the breeding season starts early for Mallards. Enjoy your walks to and from work watching all the wildlife.
  • I agree with Hazel (sorry Hazel, I know my ID record isn't great Wink) . Colour variations in mallards are significant, and also the iridescence can be misleading depending on the light conditions, I've seen some that look blue headed from one direction, but green headed from the other, simply because of the way the light was on them

  • Thank you for the replies, I was having another look at them this morning with my partner who mocked me for my “giant duck” theory. Looking at them again the body shape, the way they walk, colour of the head is closer to black and the pattern of the body feathers is also different,. They were eating side by side this morning with the regular Mallard and the two of them are considerably larger than all the other mallards, my partner conceded that I wasn’t crazy and said they look more goose like in size and shape. My tin foil hat still feels justified at this point, I’m not a bird watcher or duck enthusiast but I observe them daily and these two are definitely new on the scene, I’ll try and get a better photos of them with better perspective.
  • No worries SquidRings, ducks can vary, even the same species depending on their stance, sun, shadows and even plumage differences so no one will mock you on the forum as we've all been there, done that and got the duck tee-shirt lol I have even seen what I thought was a small brown bird but later it turned out to be a curled up autumn leaf in the shape of a bird's head and body ! Happy bird watching.
  • It is fairly common for Mallards to breed with domesticated ducks (which are often bred for size) and the resulting offspring are often slightly larger than normal and they come in a whole variety colours. These are often referred to as Manky Mallards as they are not pure breeds but still hang around with other Mallards. I think it is distinctly possible that you have a couple of those but with minimal plumage differences to ordinary Mallards.
  • Thanks Nigel! I had suspected they were some sort of cross breed. Manky Mallards and the Rouen Duck had come up on google but I wanted to check with people in the know incase they were something exotic.