I find Coots:
a) quite boring to shoot
b) quite difficult to shoot well;
the head usually goes quickly fore and aft, often giving an unsharp eye - I guess this is in time with their paddling (counter balancing those huge feet? - this looks to be caught at the "head fully forward, feet fully aft" point of the cycle)
the white bit often blows, or you lose detail in the black plumage, unless the light is favourable and the exposure good, as it is in yours
I also find the reflection in shots like the Coot can also "throw another spanner in the works" (by being comical/distracting at times), but this is fine - (although you could possibly cloned out the foreground bit of stuff that has "split its head")
I can sympathise with the problems of distant birds buried in trees too, well done on that first Harrirer shot.