Puffins are under increasing pressure from climate change Reuters

Over a quarter of the bird species in the UK are now of "highest conservation concern" according to a new report, Birds of Conservation Concern 4. A total of 67 of the UK's 244 bird species are now on the report's Red List - 27% of species.

The report was compiled by a number of bird conservation groups including the British Trust for Ornithology and the Royal Society for the Protection of Birds (RSPB). The last such assessment on British bird species was carried out in 2009 and listed 52 species as being on the Red List.

One of the species joining the Red List for the first time is the puffin. The sea-bird has been recently labelled as globally threatened with extinction, one major factor behind this being climate change with warming seas which affects the puffin's food supplies.

Another UK species now deemed under threat is the nightingale. There has been an 85% decline in the breeding population of nightingales since 1970, according to the RSPB. The curlew has also seen a sharp decline of 62% of the breeding population since 1970 - this is particular devastating as 25% of the world's curlew population breed in the UK.

A report by RSPB Scotland highlighted the worrying decline of curlew population by calling for the bird to be the UK's highest conservation priority.

Groups did highlight that the report also showed that targeted conservation efforts were helping species previously at threat. For example the red kite, previously on the Red List, is now on the Green List. Other birds like the bittern and nightjar were moved from the Red List to the less severe Amber list.