At first glance, the nightingale is surprisingly modest. About the size of a robin, it is a plain, warm brown bird with a soft, pale underside and a distinctive rufous-tinged tail. Its large, dark eye stands out against otherwise simple plumage. Males and females look almost identical, and their secretive nature means they are rarely seen clearly, slipping through dense undergrowth with ease. Instead, it is their voice that gives them away.

The male is one of the most accomplished singers in the bird world, producing a rich, powerful stream of whistles, trills and bubbling notes. With a repertoire of hundreds of phrases, his song rings out both day and night, often delivered from a hidden perch within thick vegetation. Night singing is especially important at this time of year, helping newly arrived males attract a mate and defend their territory without competing with the daytime chorus of other birds.

Breeding begins soon after arrival. Once a pair has formed, the female builds a neat, cup-shaped nest low to the ground, tucked into dense scrub or bramble. Using leaves, grass and twigs, she creates a well-hidden cradle for her clutch of four or five olive-brown eggs. While she incubates them, the male continues to sing, though less intensely once paired. After around two weeks, the chicks hatch and are fed by both parents, growing rapidly on a diet of insects, spiders and other small invertebrates gathered from the leaf litter below. Within days, the young birds leave the nest but remain dependent on their parents as they learn to forage in the safety of thick cover.

Yet despite its celebrated place in our culture, the nightingale is in decline. It mostly breeds in Southeast England. In Hampshire, numbers have fallen by around eighty per cent since the 1980s. As dense, scrubby habitat has declined or become fragmented, so too has the species. Where nightingales persist, it is often thanks to careful habitat management that maintains the tangled undergrowth they need to breed.