Long-tailed blue mating pair (Sussex)

[Max Anderson]

9/9/2020 - Whitehawk Hill

A day to remember..

Whilst chasing some pristene individuals for a photo (estimates of 8 or 9 males and 2 females), Neil Hulme told me he had eyes on a male and female a few yards away, and that it looked as though the male was trying to mate. The two flew up and landed on some bramble leaves and the male persisted to pester the female.. See the link below for a video of what followed.

https://youtu.be/RyEIQ_v-Z_E

[Padfield]

A day to remember indeed - a really rare sighting. Well done on getting that footage. I didn't expect him to get his way at the beginning but persistence paid off!

Guy

[David M]

Fabulous footage, Max. As Guy says, it didn't look too promising at the start...

[Kevin64]

Fabulous capture, as I have never had the fortune to see a Long tailed Blue, I hope you don’t mind me asking where this was in Sussex. Fully understand if you are unable to.

[Vince Massimo]

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Vince

[Max Anderson]

Fabulous capture, as I have never had the fortune to see a Long tailed Blue, I hope you don’t mind me asking where this was in Sussex. Fully understand if you are unable to.

This was at Whitehawk hill in Brighton.

[aeshna5]

Interestingly there was a colony at exactly this same location last year. Given last year's mild winter I wonder whether they were able to successfully over-winter here in the way some Clouded Yellows do along parts of the Dorset coast? Given there doesn't seem to be a wide influx of LT Blues this year unlike last year it does seem quite a co-incidence they are in exactly the same place. Gather there's at least a dozen individuals there.

[Padfield]

Interestingly there was a colony at exactly this same location last year. Given last year's mild winter I wonder whether they were able to successfully over-winter here in the way some Clouded Yellows do along parts of the Dorset coast? Given there doesn't seem to be a wide influx of LT Blues this year unlike last year it does seem quite a co-incidence they are in exactly the same place. Gather there's at least a dozen individuals there.

I have no evidence either way for this colony, but I do know that long-tailed blues have an uncanny way of finding exactly the same spots year after year. There is a hill with bladder senna on my local patch in Switzerland where they appear without fail every July, setting up territories in the same corner of the same field. Even in years when I see no others elsewhere, I see them there. They then breed and are still flying in September, but the winter kills them and we have to wait until July again for the next wave.

The species has no natural diapause, so far as I know, so continuous presence at the same site should be noticed outside the high summer season.

Guy

[bugboy]

Interestingly there was a colony at exactly this same location last year. Given last year's mild winter I wonder whether they were able to successfully over-winter here in the way some Clouded Yellows do along parts of the Dorset coast? Given there doesn't seem to be a wide influx of LT Blues this year unlike last year it does seem quite a co-incidence they are in exactly the same place. Gather there's at least a dozen individuals there.

I'm seeing this spoken about a lot on Facebook at the moment but I think people are just overthinking the situation. It's really no different from a lone buckthorn in a hedgerow having Brimstone eggs on it year after year. The fact that they turn up in successive years isn't coincidence, it just proves this is a suitable spot for them to breed. This particular site has a double whammy of having the foodplant making it attractive to gravid females as they make landfall, and also being a hill so the resulting progeny will hang around and exhibit hilltopping and lekking behaviour. They have been seen at various other sites along the Sussex coast this year but mostly further west than in previous years.

You need to think of the northward migration as a wave, they'll make landfall all along the coast but in ones and twos and will for the most part go under the radar at all but the most well known and most monitored sites. These will then home in on suitable foodplants and off course despite them having a wide range of foodplants here in the UK we've become focused on BLEP so we always check the same sites. The overwhelming amount of evidence supports the theory of a southward migration by the first generation Individuals that get all the attention at this time of year.

[Padfield]

Just to add to what Buggy wrote, the site I was referring to in my post is also a hill - in this case, sticking up out of the Rhône Valley. Long-tailed blues are classic hilltoppers. I suspect there are all sorts of other topological and ecological cues that lead them to converge on the same places year after year, like WhatsApp invitations to a rave.

Guy

EDIT - I've no idea what WhatsApp is and I don't really know what a rave is.