The Annual Tansy Beetle Survey

In mid-August, the new generation of tansy beetles emerge from pupation and an army of volunteers start surveying the banks of the River Ouse around York, recording the location of every tansy clump and the number of beetles on each. Last Saturday I took my friend Meg to Naburn Lock and then drove round to Cawood Bridge, further down river. She walks south and I walk north, and we meet up around Stillingfleet.

Tansy amongst the Himalayan balsam

After half an hour of recording tansy plants, I stopped for a coffee break on the flood bank. A roe deer came out of the Himalayan balsam that lines the river bank here, stopped to look at me, and then bounded away over the flood bank and into the wheat field behind. I then walked a long stretch with nothing but Himalayan balsam about 10m deep, before reaching an area of 'waste' ground covered in nettles 2m high, willowherb, bindweed, and hidden in the middle, some clumps of tansy. Here there are beetles, and after an hour of fighting my way through the undergrowth, I'd found 99 of them, a new record for my stretch.

Tansy beetles

I stopped for lunch and found a bird pellet lying in the grass on the flood bank. I tried to put it in a bag to bring home, but it was so fresh that it just fell apart. It was full of seeds, rather like the cereal bar I'd just eaten. I think it was from a rook.

Rook pellet

After that, I got into cattle pasture. Several buzzards were mewing overhead and I kept disturbing a heron which flew up-river, only to be moved on again when I caught up with it. I met up with Meg at Stillingfleet beck and we walked back to Cawood. According to my GPS, I'd walked 12.4 km (7.7 miles).


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