The soft, sandy soil is damp after the heavy overnight rain. I follow the narrow track downhill, splashing through large muddy puddles, and head out across the heathland. The sun pierces through the lifting cloud and shines on a tree pipit, singing from the top of a tall silver birch. The pipit’s trills and whistles carry across the undulating heather and scattered trees. The song ends with falling glissandos as the bird flutters down, out of sight among some ferns.
Tree pipits are getting harder to find on these Sussex heaths, especially in West Sussex. A 1967-70 survey estimated a breeding population of around 600 pairs across East and West Sussex. That fell to 90 pairs by 2010. It reflects a steep decline across England, although they are on the rise in Scotland.
The reasons for their falling numbers in England are unclear. Tree pipits are ground-nesting birds and prefer open or cleared areas, with some tall trees to use as song posts. It has been thought that maturing heathland and woodland habitats may have led to reduced breeding success. Research suggests that nest failures may also be caused by increases in predation and human disturbance.
Further on, I hear the scratchy, muttering calls of Dartford warblers, and catch sight of two darting over the heather. Careful, rotational management of the vegetation is important for the Dartford warblers, too – and for other specialists of heathland, including woodlarks and nightjars – to ensure a continuous mosaic of open ground, heather, gorse and a mix of young and more mature trees to provide food and cover. Left untended, the landscape would revert to dense woodland.
The wet path wanders between tall ferns and past a still, open pool. Large green-blue beautiful demoiselles fly over the track at chest height, their wings making pattering sounds. The males are patrolling their territories and waiting for the green females. A male lands on a broad fern leaf in front of me. It takes off, hovers in a circle, then returns, its metallic blue body and wings glinting in the sunshine.
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