The One Show

Conker Tree Science has made it to primetime television (again). We've been working with Icon Films in Bristol to produce a mini-documentary about the project for The One Show, which will be screened tonight. We're hoping that the speeded up footage of the moth larvae attacking horse-chestnut tree leaves will have made it to the final cut, along with us talking about blue tits feeding on the moth larvae and pupae. Thanks to Mike Dilger and the Icon Films team for making the production such fun. We can't wait to see how it has turned out...

And the great thing is that the story of the blue tits attacking the 'alien' insects is not finished yet. It is real on-going science. And it's not done by 'professional' scientists in white coats sitting in labs - it's done by anyone! It is not hard to take part (it could be a perfect activity for families this weekend) - so go to the mission page main website to find out more.

Bird attacks!

Can blue tits save our conker trees? You could help us find out. It will only take a few minutes and, with enough records, we can begin to understand how blue tits are responding to the horse-chestnut leaf miner. We launched the mission last year, but we hope to have more records this year.
We know that blue tits (along with great tits and coal tits) do feed on horse-chest leaf-miners. They peel open the leaf mine to extract the pupa inside.

You might have noticed blue tits feeding in the canopy of horse-chestnut trees, but bird-attacked leaf-mines are easy to spot and count. (Photo by Richard Broughton)

But which trees to they attack? Is it any tree, or do they preferentially attack the most infested trees and leaves?
And, does that activity occur everywhere? Or is it a behaviour that is spreading across the country (such as when blue tits learned to attack milk bottle tops to get the cream)?

The evidence of bird attacks. Look for these and count them to take part in the bird attacks mission of Conker Tree Science (you don't have to wait to watch the birds themselves).

Download the instructions, spend a few minutes counting bird attacks on horse-chestnut leaves (it's an ideal activity to do with children, but adults can do it on their own as well!) and then submit the results. With enough records we should be able to answer these questions - so by counting bird attacks you'll be contributing to real science.

The state of our conkers

Earlier in the summer I commented that the horse-chestnut trees in my area weren't too badly affected affected by the leaf-miner. What is the situation now?
Well, my impression is that the leaf-miner damage is a lot more variable than in previous years. By this time of year I would have expected almost all the horse-chestnut trees to have completely brown leaves that were curled up and dry (especially at the base of the crown of the tree). Instead some trees are badly affected (though maybe not as much as previous years?) while other trees are much more lightly affected.

A badly affected tree (complete with conkers) in my village. I think the trees were even more badly affected by the leaf miner last year. From research published last year, those conkers will be smaller than they used to be, thanks to the effect of the leaf miner.

This tree, just a couple of hundred meters up the road, is much less badly affected. Last year in was affected much more badly by the leaf mine.

I still suspect that the exceptionally late spring could have caused this effect - by affecting the first generation of the leaf-miner moth, it would have had a knock on effect on the second generation. Maybe, the very local variations in shelter and warmth of trees earlier in the spring was sufficient to cause this variation? In previous years it is possible that there were so many moths anyway, despite local variations, that they quickly reached a 'saturation point' on all trees.
That's just a theory, and the fact that every year is different is part of what makes ecological science fun. But it also makes it really difficult to make precise predictions about the future!
For now though, I'm enjoying horse-chestnut trees with some green left in their leaves - something I haven't seen in September for many years.

Conker Tree Science 2013

High summer is just around the corner, which must mean that our conker trees are just beginning to turn blotchy - and so Conker Tree Science is launched for 2013. You can take part in the 'pest controller' mission over the next week, and take part in the 'alien moth' mission during the whole summer. Watch out for news about the 'bird attacks' mission which will start again at the end of the summer.

It appears that the very late spring this year has also had an effect on the horse-chestnut leaf-miner. My impression is that the leaf mines are currently smaller than I would expect for this time of year, and few have pupated (you can tell if they have pupated by feeling the underside of the mine - there is a small bump where the caterpillar has spun a cocoon and pupated). My impression is that the size of the leaf mines is also much more variable than I would expect at this time of year. In previous years all the mines of this generation have been pupating within a day or two of each other, but this year it is a lot more variable. Will your data confirm my impression? I look forward to receiving your results via the website or the leafwatch app.

These mines are only just beginning to form - they will probably pupate in a week or so. Photo taken on 4th July.

One of the few trees in south Oxfordshire that had mature mines, but it still has a lot of very small mines as well. Photo taken on 4th July.

This tree had very few leaf mines. Photo taken on 4th July.

A new year for Conker Tree Science

Once again spring is here and the horse-chestnut trees are looking stunning.

We are getting ready for Conker Tree Science in 2013. If you want to know when to start taking part please register on the website. (If you have registered over the past couple of years, then you don't need ot register again).