Nothing special in this lot … just a bunch of regulars … and one intruder.
The answer is …
Postscript … There were a number of novel, amusing and oblique answers which made me think that I should have posed the question more clearly. C – the duck, was the answer I was seeking. It looks domestic or possibly a wild hybrid with some Indian Runner … bit of a mystery really!
Many thanks to those who responded, and apologies for my slow response.