Strange behaviour

Strange behaviour

Observation - Strange behaviour. Description: Apologies for the quality of the photos. This bird, which I thought at first it was a Mallard but now think is a shoveler, kept its head low with beaak in the water as it went round in circles. It did raise its head eventually, as photo 3 shows, but when

Apologies for the quality of the photos. This bird, which I thought at first it was a Mallard but now think is a shoveler, kept its head low with beaak in the water as it went round in circles. It did raise its head eventually, as photo 3 shows, but when I was studying it, it would not raise its head. I have never observed this behaviour before. Can anyone suggest what it was doing or what may have caught its attention?