Corncrake national surveys - raw data

Royal Society for the Protection of Birds

Description

At the beginning on the 20th century, corncrakes still bred all over the UK, but by the early 1990 they were restricted to a few Scottish islands. Through conservation effort from the Royal Society for the Protection of Birds (RSPB) and NatureScot, the decline was reversed. This dataset contains corncrake records from all annual surveys of corncrake since 1988, monitoring the increase in corncrake numbers since 1993. These surveys have been funded mainly by NatureScot and RSPB, but also by other partners in SCARABBS (Statutory Conservation Agencies and RSPB Breeding Birds Scheme). For each year, the dataset contains all locations of singing males, recorded on multiple visits to each area covered. Multiple observations of the same male are labelled with a unique code for that male (calls heard on separate occasions less than 200m apart are assumed to be the same bird).

For all years since 1993, territory centres for each male, calculated from these observations, are provided in the dataset Annual corncrake surveys in Britain (territory centres).

Geographic Description

Two types of survey are undertaken. In National surveys the whole corncrake population of Britain and the Isle of Man is surveyed. In Core Area surveys, counts are undertaken on the Hebridean islands and Orkney. These islands represent the core range of the corncrake in Britain and hold more than 90% of the breeding population.

Purpose

To estimate the population size of the corncrake in the UK, and to monitor change in numbers and results of conservation effort since the low point of the early 1990s.

Data quality

RSPB fieldworkers follow the standard methodology and collect the majority of the dataset. Some records do not have a date; in this case the whole survey period (between 1st April and 31st August) is quoted. For records without a clear location at 100m precision, the 1km square is given. These data have been mapped and checked for sensitivities and typographical/geographical errors

Methods

Surveys are conducted at night. Two visits are made between 20th May and 10th July between 00.00 and 03.00 hours BST. Estimated locations of singing males are recorded in all areas known to have suitable habitat.

All verified records of nests and chicks are included. Information about daytime singing locations and records outside the census period are included only if no night-time survey work can be undertaken, for example if the area is too remote.

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

RPSB ([Insert year of download]). Corncrake national surveys - raw data. Occurrence dataset on the NBN Atlas

Rights

Please acknowledge the RSPB, NatureScot and SCARABBS (Statutory Conservation Agencies and RSPB Breeding Birds Scheme) in any use of the data.

Digitised records