Cirl bunting national surveys in the UK

Royal Society for the Protection of Birds

Description

The cirl bunting, Emberiza cirlus, is a scarce and localised breeding bird in the UK, now being confined almost entirely to south Devon. It is on the Red List of Birds of Conservation Concern in the UK owing to the rapid decline (>50%) in the UK breeding range over the past 25 years, and has been identified as a priority species in the UK Biodiversity Action Plan. Full surveys of the breeding cirl bunting population in Britain and the Channel Islands were undertaken in 1989, 1998, 2003, 2009 and 2016 to document potential range expansion.

The 1989 survey was conducted by the RSPB in conjunction with the Devon Bird Watching and Preservation Society. The 1998 survey was funded by the RSPB and Nature Conservancy Council (NCC) (now Joint Nature Conservation Committee (JNCC)). The 2003 survey was funded by the RSPB, English Nature (now Natural England) and the Department for Environment, Food and Rural Affairs (Defra). The 2009 survey was funded by the RSPB and Natural England. The 2016 survey was funded by Devon Birds, Devon County Council, National Trust, Paignton Zoo, RSPB and Teignbridge District Council.

The surveys were carried out under the Statutory Conservation Agencies and RSPB Breeding Birds Scheme (SCARABBS) partnership.

Geographic Description

The surveys were conducted primarily in Devon and were based on the species' known range. Searches were also carried out in Cornwall, Somerset and the Isle of Wight where there had been recent cirl bunting sightings. Records for Jersey will be provided when mapping for the Channel Islands becomes available on the NBN.

The majority of the records are at 100 m resolution. Some records in the 1989 survey are only available at 2 km resolution.

Purpose

The objectives of the survey were threefold: a) to conduct a full survey of the known range; b) to survey areas bordering the known range to assess potential range expansion; c) to cover sites with recent records of cirl buntings.

Data quality

These data have been gathered by trained field-workers and the data are of a high quality. These data have been mapped and checked for sensitivities and typographical/geographical errors.

Methods

The survey area was derived from the occupied tetrads (2km x 2km squares) found in 1989, in addition to those tetrads known to have been occupied in subsequent years. In an attempt to identify potential range expansion, areas around the core tetrads were also surveyed. Each tetrad was visited at least twice during the breeding season. The first visit was made between mid April and the end of May, the second between the beginning of June and the end of August, with a minimum of two weeks between each visit. Some tetrads were visited four times. The tetrads were surveyed by walking public rights-of-way and areas of public open space. Permission to enter private land was sought where necessary. The tetrad coverage was directly comparable with every cirl bunting survey in southern Britain since 1989. Locations of any cirl buntings seen or heard were recorded on a map of the tetrad using standard BTO mapping symbols to denote their behaviour and breeding status.

The cirl bunting is a difficult species to detect at very low densities, when song activity may be infrequent. Consequently, there is a possibility that some birds have been missed in tetrads at the edge of the range. The UK population estimate must still be regarded as a minimum as it is likely that concerted search effort allowing unlimited access in the tetrads would pick up more territories.

In order to verify records and validate the dataset, the data have been mapped and thoroughly checked. Geographical checks have included comparing the distribution with that shown in the published paper and ensuring that records with the same area name are located close to each other.

Citation

The Royal Society for the Protection of Birds ([Insert download year]). Cirl bunting national surveys in the UK. Occurrence dataset on the NBN Atlas

Rights

CC-BY

Digitised records