The pigs Hazel and Beech have left the reserve, leaving a large section of the boggy area below the concrete causeway nicely churned up. We wait to see what germinates from the seedbank in the puddled peaty soil. Elsewhere on damp banks and woodland edges, the first of the buttercup family on the reserve is flowering.

The glossy yellow petals of lesser celandine Ficaria verna only open in sunshine, held in a parabola to reflect the sun inwards, raising the temperature in the bowl of the flower, a boon for early-flying insects seeking the pollen and nectar provided. Gardeners know that every bulbil at the base of the plant can grow into a new plant and botanist Alex Lockton has identified the subspecies verna in one location on the reserve, with bulbils developing in the leaf-axils just to help spread it even more quickly.

The heart-shaped glossy leaves are rich in vitamin C so were used against scurvy. The entire plant withers above ground as stronger plants and tree cover cut out the essential sunlight, food stored in the bulbils for its early appearance next year. Ficaria derives from ficus, fig-shaped. Wordsworth wrote three poems about lesser celandine, and sent a pressed sample to Scottish zoologist Adam White from a sunny slope within a few yards of my house which I call Celandine Bank - it is so richly starred with that favourite plant of mine. The celandine carved on Wordsworth’s memorial in Grasmere church looks more like a greater celandine, Chelidonium majus in the poppy family, although the sculptor Thomas Woolner denied that.  

In scrub just a few inches above these low-growing shining stars it’s already nesting time for birds such as dunnock, wren and whitethroat. The dunnock, Prunella modularis, is an inconspicuous solitary all-year resident the size of a robin, a warbler with a gentle jingling song and a "tseep" that can become an alarm call. It forages for insects, spiders, and worms shuffling along close to the ground, adding seeds and berries to its winter diet. The quiet plumage of browns, black, and grey provides good camouflage against predators, and is subtly tweedy seen close-up. Known as hedge sparrows to many, they can be distinguished from the distantly related sparrows by their thin pointed bill, notched tail, habit of keep low to the ground, never feeding on bird tables, and frequent wing flicks.

Some overwintering continental dunnocks will leave soon, while low courting flights and aerial chases with quivering wings start here. Females will mate with more than one male, and more than one nest may be built, low in bracken or shrubs, flattish made of twigs, grass, and moss, the shallow cup lined with hair or wool. Two or three clutches of unmarked blue eggs are incubated between April and June; possibly from several males, who may help feed the broods. Sparrowhawks and cats predate the adults and cuckoos favour dunnock nests, cuckoo nestlings pushing dunnock chicks out while accepting food from dunnock parents.  

Dunnocks are the only lowland member of the Accentor genus. The old English dun- brown, + -ock, small means ‘little brown bird’ and the German name, Braunelle, is also a diminutive of brown. The easily interchangeable ‘p’ and ‘b’ resulted in Prunella;  modularis means ‘singing’. Although common, numbers declined by nearly a third from the 1970s, rebuilding slowly since the 1990s, so they are of conservation concern with amber conservation status.   

Throughout spring and summer, all birds nesting low down are highly vulnerable to disturbance by dogs running around and sticking noses into bramble and scrub, as are all the ground-nesting birds such as willow warblers, yellowhammers, chiffchaffs, tree pipit (who nest on the ground), linnets and we hope eventually the Dartford warbler and nightjar.