Nature red in tooth, claw and beak

I was trying hard not to fall out of bed the other night, the cat having annexed the bit where my legs are supposed to go, when the thought struck me that perhaps we humans over-indulge our pets. Most of us start with house rules - the animal must live outdoors/in the kitchen/never go upstairs - then before you can say "gourmet cat food" you wake up one morning with the moggie sleeping on your head.

There must be hundreds of thousands of dogs and cats in this city and most of them live the life of Riley. You only have to sit in the vet's waiting room for 10 minutes to witness the sly skill with which animals manipulate their owners. Otherwise sane humans dance attendance on their pets in the same way as they do on their children (though at least your pet is always pleased to see you).

Still, dogs and cats do pour balm onto our harried, alienated London souls. Stroking them does wonders for stress levels and blood pressure. Scratched staircarpets, upended water bowls (always difficult to prove intent with that one) and, in my case, the odd course of penicillin for an infected cat bite are a small price to pay for unconditional love.

Meanwhile, out in the garden, Darwinian natural selection is in full swing. Single-minded wildlife doesn't waste time palling up with humans, however much we like to kid ourselves. I've turned my garden into a gourmet restaurant for insects, birds and assorted mammals and they all behave badly. Once the temperature drops below zero, gang warfare is the order of the day, though mostly the birds don't have to be hungry to pick a fight.

I've just been watching the pompous male blackbird wear himself out seeing off every other bird that tried to land on my flat-roofed shed to eat the porridge oats, grated cheese and raisins I put up there (yes, I know I spoil them). He actually had a chest-butting session with a starling: a scene straight out of Mickey Rourke's latest movie. Somewhere on the sidelines Mrs Blackbird and Mrs Starling were rolling their eyes and wondering what on earth they ever saw in them.

My siskin has now rounded up three yellow chums and they're fighting pitched battles with the six goldfinches round the niger feeder. The minute the finches are absorbed in a full-on squawk-and-chest-butting session, a battalion of blue tits launches a sneak attack. The tits are smaller but fearless; they don't actually eat niger seed, they just like a scrap.

I put out enough food for every bird in the neighbourhood every day - there's no reason for them not to play nicely. But co-operation is a wholly human endeavour, as is altruism. We may have bought off our domestic pets but wild animals will always see life as a never-ending personal struggle.