The site includes Ministry of Defence land earmarked for a major housing development. More than 80 per cent of the local nightingale population is distributed across the area proposed to be allocated for development.
The decision was taken by the Natural England board at a public meeting. Lodge Hill was originally notified as a SSSI in March this year. Recent research by British Trust for Ornithology (BTO) has shown the number of nightingale pairs dropped from 85 in 2012 to 65 in 2013.
The site was combined with SSSI land at neighbouring Chattenden Woods to form Chattenden Woods and Lodge Hill SSSI. It is the first in Britain to have the nightingale – Luscinia megarhynchos – as one of its notified features.
As the Government’s conservation adviser, Natural England has a duty to notify SSSIs when it considers that an area of land is of special interest for its flora, fauna or geological or physiographical features. Selection of SSSIs is carried out in accordance with published guidelines and, once notified, the special interest features of a SSSI are given protection against operations that are likely to damage them.
Natural England chairman Poul Christensen said: "The evidence clearly points to this site being one of the most important strongholds for nightingales in the country. Confirming this land as a Site of Special Scientific Interest gives the clearest possible recognition of this."
The site’s national importance for nightingales was first established by a national survey carried out by the BTO last year. It found that the scrub and woodland habitat was home to more than one per cent of Britain’s nightingale population, making it one of the most important strongholds for the bird in the country. Further research also discovered that the site contains over 11 ha of lowland species-rich grassland.