Wednesday, 4 December 2013

Which Umber?

I had this moth down as a Mottled Umber yesterday, but in view of the ground colour and the presence of two strong cross-lines is it not more likely to be a Scarce Umber?  Another similar moth was photographed by a trap on 25 November.

25 November Moth
2 December Moth
 
 
 

7 comments:

  1. I had an identical one here last week which I thought was going to be Scarce Umber. In the end I concluded it was Mottled, but a check on UKMoths makes me totally confused. Is the yellowish ground colour really diagnostic?

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  2. I'm pretty sure that's Scarce. Mottled Umber doesn't have the dots on the outer edge of the wing, and the outer cross line is more angled.

    George

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  3. Thank you Sam & George. I was prompted to look at these Umbers again yesterday after reading a post by Tony Allenby on the Ceredigion site. He had trapped both species at the same location and posted photos of them. The main distinction that struck me was the strong, straight cross-band on the forewing at one-third. Then I read the descriptions in Waring and Townsend, particularly: 'Mottled Umber never has golden ground-colour'. I have since revisited a photo of one I saw on 25 November with the same features, and will add this to the blog. Yet another 'Winter Dilemma'!

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    1. Perhaps the 25 November moth is a less convincing candidate for Scarce than the other because the indentation on the outer cross-line is deeper, yet it has the golden ground-colour and bears a fair resemblance to one of the photos of Scarce in Chris Manley's book (p160).

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  4. The straightness of the post-median line across the dorsal half of the wings rules out Mottled, my only concern would be very early Dotted Border. However, given the time of year and the rich colour (probably exaggerated in camera by the background colours) I'd go along with the general consensus and go with Scarce, but not with 100% confidence. I believe both specimens are the same species.

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  5. Just looked at some pics of Dotted Border and this invariably shows a line of pale sub-terminal blotches so very happy both are Scarce.

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  6. Thanks Barry, I'm very grateful for your input. I can't remember the 25 November moth in detail, the photo was taken at 7.16am so I might well have used flash, but believe me the image does not exaggerate the colours of the 2 December moth, the photo was taken because the appearance of moth was so stunning, I assumed it to be another Mottled Umber at the time so probably wouldn't have photographed it otherwise.

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