Louisa Pearson: Climate change supporters probably envisage our skies full of parakeets MANY things spend time on the window ledges of my home. It might be a jug filled with freesias, a miscellaneous piece of tat, rashly purchased on holiday, or a thin layer of stour. None of these things would be out of the ordinary. Unlike the sight that greeted me a few days ago: a bright orange butterfly, sunning himself on the ledge. Issue number one: it's January. Issue number two: fear of butterflies ranks high on my list of neuroses. Things went from bad to worse after I scooped him into a plastic tub and gently put him outside (feeling the fear and doing it anyway- after all, the winged critter could have flown at me, got tangled in my hair and driven me insane). I began to worry that I'd sentenced him to death by putting him out. If only he hadn't chosen my living room for his winter sunbathing. Doubtless you'll have heard about the paper published in Nature Geoscience, which speculated that the next ice age is being postponed because of all the carbon dioxide emissions we're creating. Climate-change deniers hailed this as good news, while completely failing to think it through. They are dreaming of vineyards, beach volleyball and siestas in the new hot Scotland, whereas I'm thinking about the influx of deadly insects. Tropical countries may facilitate sunbathing, but to balance things out cosmically they have been dealt myriad critters that can kill you. In climate-changed Scotland, the butterfly on my window ledge would have been a foot long, carnivorous and hungry. Call it a healthy fear of nature, call it paranoia, but every day I fight my instinctive reaction to birds, insects and animals. Instead of hiding from them I try to appreciate them. In this spirit, I give you a week's notice of the RSPB's Big Garden Birdwatch (January 28-29, www.rspb.org.uk). The charity asks you to spend an hour cataloguing the birds in your garden, local park or other suitable area, in order to build up a picture of our bird populations are. I wonder if birds in your house count. For it is not just butterflies that squat in my hovel. A few months back, a wren chose to hang out in the bedroom. Cleaning up the mess while wondering if it was still hiding somewhere had my nerves in tatters. Every time I open the stove door, I now fully expect a soot-stained crow to fly out. The horror, the horror. Last year's Birdwatch saw 609,177 people taking part, logging more than ten million birds. The top three in Britain were house sparrow, starling and blackbird. I'm pleased to report that the top three in my area were more colourful - chaffinch, house sparrow and blue tit. The climate change supporters probably envisage our skies full of parakeets, like the ones in London, as temperatures rise. Farewell drab British wildlife, hello flamingos, toucans and those birds that sound like chainsaws. For more than 30 years, the RSPB's survey has highlighted success stories and downward trends for our birds, such as the drop in starling populations by 79 per cent since 1979. The 2011 results were cautiously positive, with a rise in sightings of such small birds as goldcrests, long-tailed tits and coal tits. The hour we spend logging birds helps to shape the RSPB's work, and monitoring their numbers provides an insight into the health of the wider environment. So will I be taking part in the Big Garden Birdwatch? Yes, but with the windows tightly closed.