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Groups of up to 20 of these male flies were sunning themselves on leaves in my garden today. Can anyone say what they are? Graphomya maculata?? or something similar?

Wiltshire, southwest UK 10.4.10

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Here's a bigger group.

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All Musca autumnalis male......waiting for the girls to come :D

Joke

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Thanks Joke for the ID and yes, i am sure they are waiting (more weeks than usual this spring too...) and the first females to arrive will be very popular!
Nick

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OK the females began to arrive and the full behaviour of these aggregating males seems clearer. They mass on leaves in big groups 30-40 at times now and then suddenly a lot take off at once, buzz noisily around and land again. I think the take offs probably coincide with females flying nearby as the day this new take off behaviour became obvious, I found pairs of mating M. autumnalis on nearby leaves. Maybe the massed males attract the females who fly by and encourage force them to compete in their air for females (with some prallalels to "lek" mating systems in some birds, mammals and other insects). Not sure if they go into copula in the air (the paired flies can fly in tandem for sure) or more likely together and then court further before mating. As a behaviourist by training, I'd be interested to know if anyone knows if this has been described before in M. autumnalis. I can find a few references to close quarters pheromone use in courtship, but not to this massing behaviour of males. Here is a mating pair and then one of the male take off flurrries.

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A male take-off flurry.

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Nice photos..!
Mostly these flies are of minor importance for many photographers, because of the generality...
So nice to see a common fly...in the attention for once ;)

Joke

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Thanks Joke. I tend to photograph whatever takes my interest and for me, behaviour even of common species is often worth a close look (and when I see an insect doing something, I often don't know if it's a common or a rare species anyway!).
Nick