Ferruginous Duck or Hybrid?

This Duck was found during one of my "Ducking" trips to Maribosøerne, a larger lake area in the south of Denmark. The bird was first seen on August 29th. 2010, and the again Spetember 12th 2010. The bird might be identical to a bird seen September 26th. 2009, which first was ID`ed as a Ferruginous but this might be wrong.

It is obvious that Ferruginous Duck has a influence in the bird, but is it a genuine Ferruginous? When we saw it in 2010, we were convinced that it was a hybrid, due to the fact that the bird is very pale.

Ferruginous Duck or Hybrid, from video, note that the flanks and the breast is quite pale compared to the head.

Ferruginous Duck or Hybrid, on this shot the bid seems to be almost Female Tufted Duck-colored, but note how the white vent seems to reach the side of the pump.

Ferruginous Duck or Hybrid, on this photo it seems ok for a Ferruginous Duck, blackish upperparts, burgundy brown flanks and head, and a large white vent patch.

Ferruginous Duck or Hybrid, on this shot it really seems to be bright, and it also seems to have some greyish feathers in the back. Note also the bill, which has a black tip to a all dark greyish bill.

Ferruginous Duck or Hybrid, the headshape is steep in the forehead, and it has a rather big bill. On a genuine Ferruginoud the forehead is normally more rounded and the bill is slimmer.

 Ferruginous Duck or Hybrid, again its a dull bird whit a large bill. Note the light marking along the bill.

Ferruginous Duck or Hybrid.

Ferruginous Duck or Hybrid, the wing stripe is in my opinion not all there, it seems to small, and in my opinion it is greyish in the primaries. The belly is however in favour of a genuine Ferruginous Duck, due to it´s clean white appearance.

All videos of the bird;

Comments on the ID on this bird is very welcome!