Michael McCarthy: The countryside teems with life now

Science notebook

Busyness is not normally an attribute one would associate with the natural world, but it is one that is noticeable to a degree at the moment: everything, from plants to caterpillars, from songbirds to tadpoles, is frantically busy. This was borne in upon me during the Easter break when I escaped with some of my family to Dorset and was particularly taken with the activity of rooks.

Although central London is packed full of solitary, sinister-looking carrion crows, it is entirely free of their lively corvid cousins, very similar in appearance but distinguishable by a white face patch and a domed head. This is because rooks, above, need ploughed fields to forage for the insect larvae on which they depend, and ploughed fields are now simply too far away to allow an inner London roost; London's last rookery, in the south-eastern suburbs, disappeared after the Second World War.

But get properly out of London and rooks seem to be everywhere just now, partly because many of the trees have not yet leaved and rookeries are very visible, as is the activity they are generating: the comings and goings, with the nesting season in full swing, and the cawings and the squabblings make any rookery seem like a supermarket on a Saturday afternoon. Drive through rural Hampshire and into Dorset and there seems to be a rookery every half mile, small housing estates in the high branches. In Dorchester there is even a rookery in the town centre, right next to the war memorial.

Dorchester is a peerless county town not least because rich countryside surrounds it on all sides, and walking along the banks of its river, the Frome, I saw my first swallows of the year swooping for waterborne insects. In a privet hedge in a Dorchester street I saw something more remarkable: two tiny birds dashed into the branches barely a foot from my face, and when I peered in I saw they were bright green with orange tops to their heads; they were goldcrests. A moment later I happened to glance up into the sky and saw the reason for the dashing: a sparrowhawk was wheeling and circling, like a miniature buzzard. Frantic activity everywhere.

Return of the cuckoo

The countryside gets even busier now when some of the key spring migrant birds return, certainly to southern England; there will be a change from what you could see and hear over the last weekend and what will be audible and visible over the next. In particular, cuckoos, right, will come back this week to those areas still lucky enough to have them, as will nightingales, but both are on steep slopes of decline.