Unfamiliar Egrets and Waders (Tokyo, Japan) (1 Viewer)

[johnallcock]

I am adding some further comments and photos just to complete the thread, or at least make it more information-rich.

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Preface: I said in my original reply to James that Intermediate is a summer bird and summer is over. What I should have said is that in May/June/July they are around and breeding, and I don't see them later, but in September we still get a few (and locally a lot) of migrating individuals from further north - so, if it seemed that my comment suggested he couldn't have seen Intermediate last week, then I apologise.

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The Japanese for these birds translates as 'Big Egret', 'Medium Egret' and 'Little Egret'. (I translate as 'Medium' because 'Intermediate' seems to more directly reference the bigger and smaller versions than the Japanese does.)

In my area, at least, if necessary when both are present, among birders alba is 'Big Big Egret' and modesta is 'Medium Big Egret'. As I said above, alba has become increasingly common in winter in recent years and where it was once something to get excited about, it no longer is particularly special.

Referring back to Butty's important point in #6, in our area, difficulty in judging an individual bird by size arises as a problem with differentiation between modesta Great and Intermediate in the summer, and this is when the 'eyeline test' is useful; alba is so much bigger than Intermediate that it would not be a problem.

I attach a few photos to illustrate.

Photos 1 and 2 show two Intermediates with a modesta Great.

Points to note:

The 'kink in the neck' theory of differentiation doesn't hold - both species can do both, although perhaps not as often as each other.

In the field at a certain season, the size difference, as Butty correctly says, is not apparent when only one species is present (and even then, crouching and general posture, especially when the birds are far away, can cause problems).

Photo 3 shows modesta Great on the left, Grey Heron in the centre and Intermediate on the right. Photos 4 and 5 show the eyline of the Great and Intermediate.

Points to note:

Mark Brazil's 'Birds of East Asia' says that modesta is slightly smaller than Grey Heron, and alba is slightly bigger, in general. This seems reasonable. The Grey in this photo is several metres in the background and the modesta in the front.

Again, the kink in the neck theory doesn't hold, as the bird on the right is Intermediate.

Looking at photos 4 and 5, even the eyeline can be difficult to use, as I said in my first post in this thread. While the Intermediate is obvious, the eyeline of the modesta Great is not so evident on this individual, because of wind/water or whatever, so if we saw just this bird it might not be evident which it was of Great or Intermediate. But with the larger picture available, we can make these judgements.

This post isn't challenging or supporting any other posts; I simply hope it provides some food for thought.

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Postscript

I'd like to thank John Allcock for his post #9. Over the years, he has helped me a lot through his posts from near but not-the-same HK

View attachment 1530572View attachment 1530573View attachment 1530574View attachment 1530575View attachment 1530576

Errr. Just to confuse things, I'm going to jump in to say that the bird on the right in photo 3 looks like a Great Egret to me, based on head & bill shape, neck length, and 'hunchback' posture. It's interesting that it looks so much smaller than the Great on the left - I'm not sure if that could be due to distance, individual size variation or subspecies differences.

I've mentioned before in this forum that I personally find the gape pattern is confusing, hard to see in the field and not as helpful as is often suggested. I wonder if it varies geographically or if it's better considered as a one-way feature - a bird with obvious long gape should be a Great, but if you don't see a long gape it doesn't mean the bird is an Intermediate.

Once you're familiar with Intermediate they are actually fairly distinctly different (sorry, I know that comment doesn't help beginners or visitors!). I personally find structural features (head & bill shape, neck length & shape), behaviour (Intermediate tends to be in more vegetated, marshy sites) and plumage (adult Intermediate usually has longer plumes on the breast) to be useful features. As MacNara mentions above, confusion with (Eastern) Cattle Egret can be as much a problem as confusion with Great.

 

[MacNara]

Errr. Just to confuse things, I'm going to jump in to say that the bird on the right in photo 3 looks like a Great Egret to me, based on head & bill shape, neck length, and 'hunchback' posture. It's interesting that it looks so much smaller than the Great on the left - I'm not sure if that could be due to distance, individual size variation or subspecies differences.

Just on this one point, John: I played Devil's Advocate and put up photo 4 which is the gape line from the right bird in photo 3 which looks clearly short; and also the gape line from the left (bigger) bird. There is no effect of 'distance' - the three birds are in a plane - it's why I kept this photo.

All I can say is that the left bird is not alba (I hope you agree) and therefore the size diffference with the bird on the right should mean something + the gape line seems clearly different.

But that is all I have on these three,

 

[THE_FERN]

I can't imagine anyone using Opus as a main source for species ID, so I don't think you need to be excessively precise.

Yet.

The point is that the id q&a forum locks up lots of info which is either not in or is scattered across references. If that can be extracted and placed in one place (opus) you would have something superior to any other source.

As it is we often recycle discussions and (probably) come to different conclusions on the same points as there's no summary of past discussions, and finding and reading all the posts is difficult.

Those of us who have strong views about id would serve the interests of everyone if they could crystallise those there, therefore

(We have recently started to tag threads with useful id info for transfer. And I'm adding the variant taxonomies. But without bot access this is a bit slow...)

 

[MacNara]

Yet.

The point is that the id q&a forum locks up lots of info which is either not in or is scattered across references. If that can be extracted and placed in one place (opus) you would have something superior to any other source.

As it is we often recycle discussions and (probably) come to different conclusions on the same points as there's no summary of past discussions, and finding and reading all the posts is difficult.

Those of us who have strong views about id would serve the interests of everyone if they could crystallise those there, therefore

(We have recently started to tag threads with useful id info for transfer. And I'm adding the variant taxonomies. But without bot access this is a bit slow...)

Apologies, the Fern. My comment earlier was a bit brusque. I have found the Opus useful on a number of occasions over the years - but I am specifically searching the Opus because I know it's there. However, I have noticed that it doesn't come up often when I do an internet search for a bird (although gallery photos often do). There are so many sources these days; I don't know what you can do about this. There are a lot of queries on this Bird Forum ID forum which could have perhaps been solved by looking at Opus first, but many regular users don't seem to know it's there, or think to use it if they do know.

So, thanks for your work on improving the Opus. And apologies again.

Anyway, to repeat myself: I think it's modesta that is the id confusion possibility from the Great Egret angle. Differentiation of these two is when I use the eye-gape feature.

But in summer for breeding, Intermediate develops a black bill, and in this season, at least in my area, Little Egret is also a confusion species. It links with or overlaps Intermediate in size, and if you can't see the feet, it can be a problem. There are differentiation features apart from the feet (the dagger-like bill of Little, for example), but at a distance it can still be difficult to know. And especially so for less experienced birders.

Attached:

Intermediate
Little
Great Modesta

 

[Butty]

['Photo 3'] There is no effect of 'distance' - the three birds are in a plane

I think the bird at left is significantly closer.

 

[MacNara]

Errr. Just to confuse things, I'm going to jump in to say that the bird on the right in photo 3 looks like a Great Egret to me, based on head & bill shape, neck length, and 'hunchback' posture. It's interesting that it looks so much smaller than the Great on the left - I'm not sure if that could be due to distance, individual size variation or subspecies differences.

I think the bird at left is significantly closer.

For the past fifteen years or so, I have gone for a walk a few times a week to this spot that I like.

It's just (100m or so) north of the Palace site of Japan's first capital from 710 ad. It has a pond (i.e. the pond in some of the photos I post) named Mizukami or Minakami which was mentioned in poetry of that time. Next to the pond, there are a number of 'Kofun' keyhole-shaped mound tombs which like the pyramids and various tumuli in Europe required vasts amounts of labour just for one or a few rich dead people. Our largest (just next to my photos) is 260m long and 16 metres tall - and because people are not allowed entry these become miniature nature reserves.

The photo which John and Butty are referring to is a spit into the pond. It's opposite where I park my car on a grass verge next to a rice field (why don't I walk? - because it's a 3km ugly concrete road, I have a lot of expensive camera gear, and I usually do shopping on the way home).

There is at most a metre or two in distance (near-far) between the white egrets on the left and right. And a couple more between these and the Grey Heron.

The bird on the left is not 'significantly closer' (Butty). The bird on the right looks 'so much smaller' (John Allcock) than the Great on the left because it is smaller. I posted the gape line photos of these two.

I understand what John Allcock is saying, but I stand by my view that the right (in the photo) bird is Intermediate (gape, plus size compared to the modesta-not-alba on the left).

And the fact that all three birds are basically in focus isn't because I'm a great photographer, but because focusing on one brought all into focus which is what I meant by saying that they are all in a plane. Which they more or less are.

Strangely, on a quick search I couldn't find a scenic view of the tree in which the three birds were perched. Only a winter view, attached.

Also, I attach a few other 'Great White Egret' photos in case anyone wants to discuss further.

The first two are alba and modesta in the same scene. I mentioned above that I think there are features other than the yellow tibia versus grey/black tibia to differentiate these. I think that the tibia-tarsus ratio is different and the 'socks/pants' come further down the leg in alba.

I also, as devil's advocate, attach a pair of modesta and a pair of alba (as I think) that seem to be of different sizes. So if you want to argue that my feeling that alba is significantly larger than modesta is not always the case, then go ahead.

 

[Butty]

🥱

 

[THE_FERN]

(Just to note: I'll probably edit the Opus entries a bit in the light of the above. Other great egrets can be confused with intermediate in other places, though, so it's not just limited to modesta. It's important to say that too.)

 

[MacNara]

I have thought about comments by John Allcock and Butty above about the three birds in my post #11, and wondered whether I am wrong about the right bird in the photo being Intermediate. However, I am still convinced that they are Great (modesta), Grey and Intermediate, left to right in the photo. The sizes match, and I also posted the gape photos of the two white egrets which confirm my opinion I think.

Just to add a little bit, today a friend of mine in his daily blog posted this photo of what he identifies as an intermediate in the same tree as the bird I identified as Intermediate in #11. You can see that the kink is there, and I have blown the photo up and I think it is clear that the gape line is Intermediate. There was no conferring, as I haven't met him in person for two or three months. I think that the kink is less often seen with Intermediate, but happens when they want it.

 

[johnallcock]

@MacNara I don't know whether you have seen this recent discussion in the taxonomy forum, which discusses Great Egret taxonomy. This indicates that current DNA evidence may favour a 3-way or 4-way split of the species (perhaps even 5-way, depending on any results from Africa).

Ardeidae

SELYS-LONGCHAMPS, M. E., 1857 Analyses d’ouvrages nouveaux: Catalogue des oiseaux d’Europe offerts,en 1856, aux ornithologistes par M. Emile Parzudaki ... . Revue et magasin de zoologie pure et applique´e9: 117–134.. sér.2:t.9 (1857) - Revue et magasin de zoologie pure et appliquée -...

www.birdforum.net

 

[MacNara]

I don't know whether you have seen this recent discussion in the taxonomy forum, which discusses Great Egret taxonomy. This indicates that current DNA evidence may favour a 3-way or 4-way split of the species (perhaps even 5-way, depending on any results from Africa).

Thank you for drawing my attention to that.

I assume that the first thing you wanted to indicate is the ResearchGate paper linked to in post #99 on the Bird Forum page you linked to. I read that and it's interesting, but it's from 2011. I'll look at later portions of the thread when I have time. Earlier posts seem to be concerned with historical naming.

 

[johnallcock]

Thank you for drawing my attention to that.

I assume that the first thing you wanted to indicate is the ResearchGate paper linked to in post #99 on the Bird Forum page you linked to. I read that and it's interesting, but it's from 2011. I'll look at later portions of the thread when I have time. Earlier posts seem to be concerned with historical naming.

Read the thread from post #98 onwards. Especially Laurent Raty's comments and species trees in posts #104, #106 & #110. The genetic distances between the subspecies are quite large, compared to some other heron species.