Siegfried ERWIN made this comment in an earlier post on the Cinnamon Bittern (Ixobrychus cinnamomeus) HERE. We are posting the account so as to make the information available to a wider audience. The original post, in French, can be viewed HERE.
“My observation on a couple of Eurasian Bittern (Botaurus stellaris) occurred in early January 2013 near Geneva. I interprete it as a form of courtship/preliminaries to copulation. No breeding has been recorded for this species in this area. The habitat is small (some hundreds/thousands sq. meters) and overgrown with reeds, with larger adjacent ponds, tree and grass areas. But bitterns have been observed there during different seasons…
“One bird was chasing the other. The supposedly male, with his puffy feathers on the neck and head, grey and blackish crown and hind neck areas appeared more extended than those of the supposedly female. She was walking 2 meters ahead, with her neck stretched, bill pointing skyward. After a short distance, not a run, but a brisk walk, the female took off with the male still following her. After a brief low flight, both landed in the same place, but now hidden by the reeds. Five to 20 minutes later, the same behavior was observed. The pair walked out of the reeds exhibiting the same postures and shortly after the female bird took off. It happened 3-4 times in slightly less than an hour. After 1-2 hour with nothing in sight, I left the area.
“As far as I am aware, no calls have ever been reported during such behaviour. And I did not hear any sound made by the bitterns during my observation. It could be that I was a bit too far to hear anything else than loud noises.
“To me it looked like a male chasing a female, but is it the usual period for that? During early January? That would give a quite long gestation (not incubation) time before eggs are laid (in the springtime I presume)? For me, a territorial fight would have been more violent, not one bird walking behind the other, and why would both birds stay in the reeds together without fighting?
“I must say that I have also made a distinct observation some days before, 20-30km away, probably not the same birds. I spotted two birds, supposedly males, facing each other, this time both with darker, buffy neck and head, heads up, and bills almost horizontal.
“I am in no way certain that they were males. It was just a guess. Nobody could tell me if only males display ‘buffy neck and head’, and no sexual dimorphism is described about this species (or at least not unanimously recognised)? In this case, both birds had their head and neck clearly erected, but this time with their bills nearly horizontal when facing each other.
“After some seconds (before I could take any pictures), the loser flew away, higher than in the supposed courtship that I describe here. The chase was short, the winner letting the former go after some time.
“If anyone has more information on this behaviour, please let me know.”