If your only experience with Hooded Merganser is of a shy and retiring bird, the birds that favor the small local pond at Los Encinos Park, Los Angeles, couldn't be further from it. I hear the first returning winter birds showed up this week and I will try and get out there to take a look tomorrow.
This shows how small the lake is. You can walk right up to most of the winter wildfowl which includes Lesser Scaup, Bufflehead and Ring-necked Ducks amongst others.
nice male Hoodie
If you think this bird in Britain is a bit too tame for a vagrant, it's lack of wariness shouldn't be a strike against it.