Tiny changes, big effects: gardens and microclimates

How did you get on in the Big Garden Birdwatch last weekend? My Wood Pigeons outshone themselves with a count of 16, and overall I counted 57 birds of 18 species. Of course there were the 'no shows' - where were my Grey Wagtail and my Coal Tit? And there was the surprise - a Starling! Woohoo! I almost never get Starlings (although it was hardly a murmuration).

Don't forget to post your results here. Low scores, no scores - they are just as important to build up the overall picture as high ones.

The first snows of the winter arrived last night here in coastal Sussex. In fact, to have any snow at all in a winter is not guaranteed here, so it is something of a Red Letter Day, and I found myself glued to the window yesterday evening watching the flakes drift down.

What a shame, therefore, to wake this morning to find that some of the snow had already gone, and the hoped-for wall-to-wall thick carpet was in fact threadbare..

Nevertheless, snow provides a chance to observe two things.

The first is to reveal the clear traces of who has been visiting overnight, and for me the patches of snow were pocked with Fox footprints, showing how much they had merrily been pottering back and forth.

The second is that snow helps demonstrate better than almost anything else how extreme the microclimates are in the garden. For example, I have two small and shallow ponds underneath a large oak tree, and yet they remain resolutely unfrozen in all but the most severe frosts. In contrast, the large pond in its very open position, which you'd think would be more stable in its temperatures given the sheer volume of water, freezes very quickly.

Here they are this morning, the shaded, frost-free ponds in the foreground, the large pond on its way to being an ice rink in the background.

Although I took this next picture a couple of years ago, I think it sums up microclimates rather nicely.

Research has shown how microclimates are actually very important to plants and to many types of invertebrates, including butterflies. In a flat lawn, the climate is effectively even across most of the area, unless it is shaded by trees, bushes, walls or fences. But just a small mound in the lawn will introduce both a warmer drier spot on the south side and a cooler, damper spot on the north side compared to the rest of the lawn. This might be all the difference a butterfly needs to warm up on the sunny side, or a beetle to resist desiccation on the shady side.

I've long been fascinated by the fact that so many gardeners seem to desire a garden that is absolutely flat, and so I'm doing some experiments, creating mini mountain ranges and valleys using log piles covered with the excavated soil from the ponds then sown with wildflower meadow seed. Already they have gained names such as 'The Northern Hills', 'The Mound', and 'The Valley', and they don't half make things more interesting for children when they visit. Here I am sowing the Northern Hills.

So far, the sunny side of the mounds are the only place I have recorded Common Blue butterflies laying eggs, despite the foodplant, Bird's-foot Trefoil, being in many places in the garden. But I will continue to monitor and see what other differences I can spot between the morning side of the mountains and the twilight side of the hills, and whether I am creating much more varied homes for wildlife as a result.