A remarkable experiment by a young ornithologist has proved that Britain’s burgeoning wild deer population is a major threat to wildlife – and birds in particular.

PHD student Chas Holt, a research scientist for the British Trust for Ornithology, has shown that a large deer population can drive birds from woodland areas – and that nightingales are particularly affected because deer clear low-lying vegetation which is a key part of their environment.

By radio-tagging nightingales in two different areas of woodland, one with deer and one from which the animals had been excluded, he showed that the density of the birds in the deer-free areas was a massive 15 times greater.

In a BTO report, he says: “The study provides compelling evidence that increasing deer pressure can have a major effect on local Nightingale populations, and potentially those of other woodland species too.

“Deer can reduce the suitability of woodland by eating the low vegetation that forms a critical part of the nightingale’s habitat. When added to the other pressures being faced by migratory birds that winter in Africa, it is not surprising that population levels of some species are falling rapidly.”