Grey Heron: Bare-part breeding plumage changes

“I had an opportunity to see and image a small flock of 10-12 Grey Heron (Ardea cine) in various stages of breeding plumage, some nesting. For birds in my region, Wells (1999) noted that ‘facial skin is not well described’. He adds that, during breeding, bills are bright orange-yellow and legs/feet rosy flesh. Having observed breeding birds at close range a number of times, I would like to add to the description.

“1. Peak breeding plumage (better called ‘mating plumage’): The facial skin around the eye turns blue-purple with pink just before the beak. The beak is pink at the base, bright orange in the middle and bright yellow at the tip – there is a gradual shift in colour gradient distally. Legs and feet are bright flesh-pink. This in addition to the fully developed black crest plumes and long white plumes of breast and scapulars (top, above)

“2. Plumage immediately before or after peak breeding: The facial skin around the eye is blue but lacks the pink immediately before the beak. The beak is less bright orange and yellow, more uniform in colour. Legs and feet are pink. Plumes are not as well developed as in the peak period. Above and below are an examples of such birds (top and above images are on same branch but at different times, different birds).

“3. Non-breeding plumage: The facial skin around the eye is a dirty black-yellow with a light yellow immediately before the beak. Note that the facial skin turns darker black before turning blue in mating birds. The beak is uniformly yellow-orange. Legs and feet are more dirty orange-yellow than pink (as quoted by some literature).

“Images above and below are examples of such birds.

“Note that birds that are incubating eggs are already in ‘non-breeding plumage’ having gone past the heightened colour changes of mating (above). Hence it is my opinion that it is better to refer to the brief colour changes we seen in herons and egrets as ‘mating plumage’.