At 11:45am, I moved on to the field next door which has some excellent blackthorn and even better looking ash trees. An excellent number of eggs were counted there last winter, including some laid directly under the main ash tree so I figured it required a bit of a stake out. Simon Primrose had already visited this tree on 28th August and 3rd September and seen 1 male each time, but what we really needed to confirm was the presence of a female. By the time I arrived at the tree, the sun was so hazy (almost completely overcast) and the wind had started blowing a gale. Not the most ideal conditions! However, I managed to confirm the presence of 2 hairstreaks, 1 definite male Brownie and im still unsure about the other one. They were both skipping around the top of the ash for a good 30 minutes. I finally hit the jackpot at 12:40pm when a beautifully fresh female Brownie appeared out of nowhere as soon as the cloud cleared off. She sat and basked half way up the tree for a couple of minutes before darting off. In the photograph to the left, I am demonstrating the correct procedure for ash bashing :)
I also had a look at the other ash trees in the same field and managed to spot a definite hairstreak that descended out of an ash and landed high up in a hawthorn bush. However, I wasn’t able to confirm if this was a Purple or Brown Hairstreak. Still, it requires some further observation, as do other trees in the area that I have on my ever growing list.
Despite multiple searches of the main hedgerows, no females were to be seen anywhere.
So, at this point, we have 3 confirmed master trees bordering the same field. Ash 1 and 2 are roughly 50m apart, and ash 2 and 3 are roughly 300m apart. Considering the concentration of eggs that were found in these locations, all 3 trees are clearly within the main colony boundary. Does anyone know how many males can occupy a moderate-large sized ash before others start being used?
Went with Simon Primrose to Shurnock yesterday but both us and the Brownies were lost in the fog. Reports from elsewhere in Worcs, however, suggests that there is still considerable activity around assembly trees which is very unusual for us in September by which time most males have normally disappeared. Gill's question about the carrying capacity of each assembly tree is an interesting one and something we need more information on. The area around Shurnock clearly has a very healthy population of Brown Hairstreaks and it may be that a higher number of males leads to greater displacement to other nearby trees than would typically be the case. West Midlands Butterfly Conservation are running their Big Ash Bash again this year and are keen to hear of any observations of Brown Hairstreak behaviour on and around ash trees. Please post any sightings or comments here or email me at mike@stagborough.fsnet.co,uk
ReplyDeleteLike Mike and others I am also very surprised at the presence of male BrH into September. This has been the case too here in my home area of Bucks/Oxon. A friend Alan Wingrove had two males in an ash in Sussex last week. This raises the question as to the likely emergence of these individuals so late in the flight season? Do all males emerge early on or is it protracted? I have always assumed the latter never having had evidence to the contrary. How late in the flight season do others find fresh males?
ReplyDeleteWill successive batches of eggs laid by a female be fertile with only one mating prior to the outset of her egglaying cycle? Mike's point re the 'normal' absence in September might indicate so? We have so much to learn!
I think "generally", the males emerge before the females but not always. This year has been a strange one. Not only has the season been late but because of the constantly changing weather, i believe we are having a much longer emergence period, hence the reason we are still seeing the males. Im unsure if a female can mate more than once but id be interested to hear if anyone has any further theories on this.
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