Juvenile Lesser Sand Plover in Japan: ID Help Needed (1 Viewer)

[noujun]

Hello everyone,

I captured this photo of what I believe to be a juvenile Lesser Sand Plover (Charadrius mongolus) in Japan about a week ago. It was roughly the same size as several other adults that were in transition from alternate to basic plumage. However, I noticed that only this individual seemed to have a thicker bill.

How likely do you think it is that this could be leschenaultii? Also, are there any specific features that would definitively identify it as one subspecies over the other? I would greatly appreciate the insights of the more experienced birders here.

 

[MacNara]

I'm surprised no-one more knowledgeable has replied, so I'lll bump this back up to the top.

You say 'subspecies' but then mention leschenaultii which would be Greater SP I think?

I live about as far from the sea as you can get in Japan, so only see these birds once in a few years. But I can't see anything that would argue against Lesser SP. It looks to me just like the bird at the top of this outline for Lesser SP.

 

[noujun]

I'm surprised no-one more knowledgeable has replied, so I'lll bump this back up to the top.

You say 'subspecies' but then mention leschenaultii which would be Greater SP I think?

I live about as far from the sea as you can get in Japan, so only see these birds once in a few years. But I can't see anything that would argue against Lesser SP. It looks to me just like the bird at the top of this outline for Lesser SP.

Thank you for your insights. I also believe it's a Lesser SP. However, several people who were observing the bird nearby insisted that it's a Greater SP. Their reasoning was based on the thicker bill of this individual compared to many others. In the Japanese birding forums I participate in, there are multiple examples of identifying SPs with bills of this thickness as Greater SP, which had me concerned.

Your response has given me confidence. Aside from the slightly thicker bill, there's no other reason to believe it's a Greater SP. So, it seems reasonable to attribute this level of thickness to individual variation. Thank you!

 

[Andy Adcock]

Thank you for your insights. I also believe it's a Lesser SP. However, several people who were observing the bird nearby insisted that it's a Greater SP. Their reasoning was based on the thicker bill of this individual compared to many others. In the Japanese birding forums I participate in, there are multiple examples of identifying SPs with bills of this thickness as Greater SP, which had me concerned.

Your response has given me confidence. Aside from the slightly thicker bill, there's no other reason to believe it's a Greater SP. So, it seems reasonable to attribute this level of thickness to individual variation. Thank you!

Leg colour, often almost black in races of Lesser.

Not that I'm particulary qualified and though I didn't post, I thought Greater too, one of the smaller races obviously.

 

[noujun]

Leg colour, often almost black in races of Lesser.

Not that I'm particulary qualified and though I didn't post, I thought Greater too, one of the smaller races obviously.

Certainly, the leg color of Lesser SP does tend to be almost black in its summer plumage. However, this individual is a juvenile, so that characteristic might not be reliable. Additionally, I've heard that the bill length can also be shorter in juveniles, making the identification quite challenging. Indeed, identifying juvenile birds seems to be a high-level task. Thank you for sharing your opinion.

 

[johnallcock]

Definitely a juvenile Siberian Sand Plover (=Lesser Sand Plover of subspecies mongolus or stegmanni: note that I think this is a very reliable split from Tibetan Sand Plover, and they are distinguishable in all plumages).

I'm not entirely sure what your concern is with bill thickness. Siberian Sand Plover has a short, thick, blunt-tipped bill. Greater (especially leschenaultii, the most likely subspecies in Japan) has a longer bill, with a pointed tip and a distinct bulging 'nail'. I would consider that the bill of Siberian seems thicker than on Greater (especially at the base), so if you think the bill seems thick I would say that this favours Siberian. Your comment that people are identifying birds with thick bills as Greater has me concerned as well!

Other useful features on this bird:

• Upperpart pattern. Grey-brown upperparts with white fringes to the feathers. Juvenile Greater (and Tibetan) have sandier upperparts with pale buff feather fringes.
• Structure. The head looks small with a rounded crown and 'hunch-backed' appearance, typical of Siberian. Greater has a larger head, flatter crown and more horizontal body posture.
• Head pattern. The dark spot before the eye and browner cheek are typical of juvenile Siberian. Greater has less contrast, and also usually has a loral stripe from the eye to the bill (the same colour as the ear coverts). The scaly pattern on the crown also seems more distinct in juvenile Siberian (as this bird).
• Breast pattern is usually a useful feature (juvenile Siberian often has a complete breast band and dark marking on flanks), but it's hard to judge on this photo. If you have more photos it might help.
• Leg colour. This bird has green-grey legs. Juvenile Greater usually has paler, greener legs than this bird. Leg colour is a more complicated feature than some books suggest, because it varies with age and season. As far as I know juveniles (of any sand plover species) never have blackish legs - this is more typical of breeding adults of Tibetan.

 

[MacNara]

Noujun: usually new members are welcomed by us older members, but no-one has done that yet. So on my own behalf, and I hope that of others:

Welcome to Bird Forum!

For myself, about 70% of what I know about birds comes from help I have had over the last 15 years from people on this site.

Your first post above suggests that you are already a knowledgeable birder. Please stay around and ask when you need to and help when you can.

Nara > Mie > Aichi !

(Location, not superiority!)

 

[MacNara]

You or any friends are welcome to my friend's photo exhibition about birds at our local spot: Nara Heijo Palace site (capital of Japan 710-784).

 

[noujun]

Definitely a juvenile Siberian Sand Plover (=Lesser Sand Plover of subspecies mongolus or stegmanni: note that I think this is a very reliable split from Tibetan Sand Plover, and they are distinguishable in all plumages).

I'm not entirely sure what your concern is with bill thickness. Siberian Sand Plover has a short, thick, blunt-tipped bill. Greater (especially leschenaultii, the most likely subspecies in Japan) has a longer bill, with a pointed tip and a distinct bulging 'nail'. I would consider that the bill of Siberian seems thicker than on Greater (especially at the base), so if you think the bill seems thick I would say that this favours Siberian. Your comment that people are identifying birds with thick bills as Greater has me concerned as well!

Other useful features on this bird:

• Upperpart pattern. Grey-brown upperparts with white fringes to the feathers. Juvenile Greater (and Tibetan) have sandier upperparts with pale buff feather fringes.
• Structure. The head looks small with a rounded crown and 'hunch-backed' appearance, typical of Siberian. Greater has a larger head, flatter crown and more horizontal body posture.
• Head pattern. The dark spot before the eye and browner cheek are typical of juvenile Siberian. Greater has less contrast, and also usually has a loral stripe from the eye to the bill (the same colour as the ear coverts). The scaly pattern on the crown also seems more distinct in juvenile Siberian (as this bird).
• Breast pattern is usually a useful feature (juvenile Siberian often has a complete breast band and dark marking on flanks), but it's hard to judge on this photo. If you have more photos it might help.
• Leg colour. This bird has green-grey legs. Juvenile Greater usually has paler, greener legs than this bird. Leg colour is a more complicated feature than some books suggest, because it varies with age and season. As far as I know juveniles (of any sand plover species) never have blackish legs - this is more typical of breeding adults of Tibetan.

Your insights are incredibly valuable. I also gained confidence that the plover on the right side of the photo I took a year ago is indeed a Greater Sand Plover. I was disappointed, thinking that this bird with a slender bill might not be a Greater because I had information that a thick bill indicates a Greater. (I'm not wrong, am I? If I am, please correct me💦) Also, information on subspecies is scarce in Japanese, and I was confused, but now I understand clearly. Thank you so much!

 

[noujun]

Noujun: usually new members are welcomed by us older members, but no-one has done that yet. So on my own behalf, and I hope that of others:

Welcome to Bird Forum!

For myself, about 70% of what I know about birds comes from help I have had over the last 15 years from people on this site.

Your first post above suggests that you are already a knowledgeable birder. Please stay around and ask when you need to and help when you can.

Nara > Mie > Aichi !

(Location, not superiority!)

Thank you for the warm welcome. I should have joined sooner. Gathering information in Japan has been challenging, so lately, I've been relying on English websites. English is not my strong suit, but I can't let that hold me back. Looking forward to interacting more in the future

 

[THE_FERN]

English is not my strong suit

Seems pretty good to me...

 

[MacNara]

Seems pretty good to me...

If your first language is Klingon, of course...

 

[THE_FERN]

If your first language is Klingon, of course...

?

 

[MacNara]

?

Just a joke. If your first language is Klingon (Star Trek), then any other language is easy - or so they say.

I agree that Noujun's English appears to be excellent, which is why I felt it was OK to make this joke. No offence intended in any direction.

 

[noujun]

Seems pretty good to me...

I'm glad to hear that! I'm looking forward to having enjoyable conversations with everyone here, and I hope to pick up some humor along the way. Thank you!

 

[johnallcock]

Your insights are incredibly valuable. I also gained confidence that the plover on the right side of the photo I took a year ago is indeed a Greater Sand Plover. I was disappointed, thinking that this bird with a slender bill might not be a Greater because I had information that a thick bill indicates a Greater. (I'm not wrong, am I? If I am, please correct me💦) Also, information on subspecies is scarce in Japanese, and I was confused, but now I understand clearly. Thank you so much!

Yes, the bird on the top right is a Greater. This shows the bill structure perfectly, with very pointed tip. Not all individuals are as clear as this bird. The head pattern is typical Greater as well.

The other bird in this photo (lower left) is interesting. Do you have more photos of this bird? It looks like it may be Tibetan (ie 'Lesser' subspecies atrifrons/pamirensis/schaeferi), which I think may be unusual in Japan.

 

[noujun]

Yes, the bird on the top right is a Greater. This shows the bill structure perfectly, with very pointed tip. Not all individuals are as clear as this bird. The head pattern is typical Greater as well.

The other bird in this photo (lower left) is interesting. Do you have more photos of this bird? It looks like it may be Tibetan (ie 'Lesser' subspecies atrifrons/pamirensis/schaeferi), which I think may be unusual in Japan.

Wow, I was so focused on the Greater that I didn't even consider that. Your insight is incredible! Indeed, the bill shape does look like it could be Tibetan. The bird on the right side of the photo is probably the Tibetan individual you're referring to. The one on the upper left is a different individual, but I had only been thinking of both as Mongolian (stegmanni).

Thank you for opening my eyes to this possibility!