Grey Herons Breeding Japan 23 March 2025 (1 Viewer)

[MacNara]

I suppose I should have posted this in the 'Bird Behaviour' sub-forum, but the fifth most recent post there was a month ago, and the people I know at BF are on this Bird ID sub-forum. Anyway, it's a male versus female ID, along with behaviour.

Grey Herons breed in my local spot in Nara Japan. All the books say that 'adult' birds change into a breeding plumage, which I have seen often; none that I have mentions any differences between male and female breeding plumage (or winter plumage for that matter).

Yesterday I came across the event in the first three photos below (there are another ten or more in the sequence if anyone is interested). As life would have it, my camera was set to photograph nearby Common Snipe (i.e. single focus, centre point), so the focus here isn't perfect.

Both birds have full breeding 'plumage' - actually for these birds, the bill colouration and the colouring of and around the eye.

My question is whether this is a breeding dance type of thing between a male and a female (like cranes) or whether it is a male against male territorial thing?

In favour of the former (male-female) is that one bird looks slightly smaller than the other and they seem to be looking at each other and so on...

Against that and in favour of the latter (male-male) is that the bird on the right appears just a minute or so earlier to have caught and eaten an Asian Swamp Eel (lots in this place); no feeding behaviour was seen. And the final photo shows one bird biting the other's wing, after which it flew away.

And that's the whole story. What do you think?

 

[johnallcock]

A great set of photos!

As far as I am aware, Grey Herons don't dance during courtship like cranes. Most herons perform their courtship display at or close to the breeding sites, often actually on the nest. I think your observation is more likely to be two birds fighting over food or foraging sites, rather than anything associated with courtship. I quite often see other herons and egrets chasing each other away from hunting sites. The fact that the birds are in breeding plumage may just be coincidence, as many birds are in breeding plumage now.

 

[MacNara]

A great set of photos!

As far as I am aware, Grey Herons don't dance during courtship like cranes. Most herons perform their courtship display at or close to the breeding sites, often actually on the nest. I think your observation is more likely to be two birds fighting over food or foraging sites, rather than anything associated with courtship. I quite often see other herons and egrets chasing each other away from hunting sites. The fact that the birds are in breeding plumage may just be coincidence, as many birds are in breeding plumage now.

Thank you John.

We have a lot of large Egrets around here, but when they clash, it's usually just a few squawks and flying near each other for a second or two.

But in about fifteen years here, I've never seen this kind of display, so I wondered.

There was an alba Great White (they winter but don't summer) nearby who didn't get involved at all.