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Of rats and tree rats


by Richard Jones

I'm well used to seeing brown rats in London parks; although it's still quite unnerving to be sitting having a picnic on the grass and have one snuffling about in the bushes nearby.


RatMy running's not going very well. I've done something to the heel of my right foot and it was pouring with rain on Sunday morning, so my heart really wasn't in it. But I went anyway, even if it was only for half an hour. Peckham Rye Park is my regular training route. There's always something to see there, even if just the sea gulls squabbling over bread thrown to the ducks on the pond.

Today it was a black rat. I can't believe it was the true 'black', Rattus rattus. That's a much smaller and sleeker beast; it must have been a black variety of the much larger and squatter 'brown' Rattus norvegicus. It was sitting beside the stream, which bubbles down through the ornamental gardens, grooming itself in the drizzle when I trotted past. Such was its striking colour that I stopped for a second look, but that was enough to draw attention to myself and it was gone. I'm well used to seeing brown rats in London parks; although it's still quite unnerving to be sitting having a picnic on the grass and have one snuffling about in the bushes nearby or see one bounding across one of the paths.

Then round the corner there's a fight between a grey squirrel and a magpie. The bird is showing its characteristic persistence by hopping and fluttering back and forth, but the squirrel eventually sees it off from whatever they were both interested in. I read in one of my old field guides that greys can be quite vicious, killing other small animals by a bite to the neck, like a stoat! Magpie made the right choice.

A more usual use for squirrel teeth is visible on several of the sycamores in the park. I've been watching these trees all year; they looked a bit peaky earlier and they are now completely dead, killed by a sooty bark disease, the fungus Cryptostroma corticale. The disease is particularly prevalent in small to medium-sized trees during times of water stress, and this summer has been dry enough to see a resurgence in south-east London. There has been speculation that grey squirrels may have something to do with the disease's spread since they apparently like the taste of the infected bark, and perhaps they transfer spores from tree to tree. Certainly these branches are scraped all over by many series of herringbone teeth marks showing where they have been chewed.

My interest in dead sycamores is in the insects associated with them. There are a whole series of rare beetles that feed on the black soot-like spores of the fungus. The largest is a whopping 4.5 mm long. Next time I pass I'll have to make sure I have a hand lens and some collecting tubes stuffed down my skin-tight lycra running shorts.



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Gardeners' World Web User 01/01/2007 at 00:00

Gardeners' World Web User 07/12/2007 at 15:25

At the end of the summer I was planting bulbs and decided our now redundant terracotta BBQ would look great in the spring with Narcissus. I'd been filling it with diseased leaves over the summer, planning to burn them but never getting around to it but I am so glad I hadn't. Deciding to remove these to fill with compost, a small nose and two eyes of a brown mouse poked out of the bottom under the grate to see who was removing their home! So, I decided having a mouse living in the BBQ was a much better contribution to nature, put the dried leaves back and the bulbs went into ordinary pots in the end.

Gardeners' World Web User 20/12/2007 at 23:23

Suzi, unfortunately you may have to call the environmental health people in. I used to feed the birds with black sunflower seed in those upside-down plastic bottle feeders and the starlings spread the seeds far and wide. I watched a couple of rats feed and collect seeds (I keep fancy rats so I was enchanted - at first) But then they brought their mates and relatives in to feast on the bounty and I had to give in and get The Rat Man in. It was awful, but there really wasn't an alternative. It turned out that next door's shed was FULL of black sunflower seeds. It was costing me a fortune! I hope you don't have to resort to the Rat Man. Good luck, Greta

Gardeners' World Web User 01/01/2008 at 00:00

Reply to Teresa. If rats are taking the bird food, it may be that you are putting out too much. There was a time when bird food was only put out in winter, or even just when snow was on the ground. Birds are very good at finding their own natural food. Try a break in your artificial feeding. This will discourage the rats and at the same time you can see whether there is a real down turn in bird visitors to your garden. Alternatively just use small feeders that hang from strings... although the spillage from these will still feed the rats.

Gardeners' World Web User 02/01/2008 at 09:11

Reply to Greta - Thanks for your concern. There are too many cats in my garden. I've never seen a rat out there although mice are regular 'prizes' in the kitchen first thing in the morning.

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