The First Atlas of Breeding Birds in Britain and Ireland: 1968-1972.

Quality Control

All the data was checked and validated as part of the atlas project. The list and number of species recorded in each 10-km square are as complete as they can be. Clearly those squares visited for less time (especially the more remote areas) are likely to have fewer species recorded and it is the rarer and more elusive species (eg nocturnal) ones which will not be recorded in these circumstances. However the maps as published are considered a true representation of the distribution of the species at a national level, while accepting that there will be some gaps in individual squares.

Method steps

1. Specific fieldwork was conducted by mainly volunteer observers although professional help was used in some remoter areas. Observers were asked to visit each 10-km square and record the presence of as many species as they could find and to note whether they were Possibly breeding (column 1) e.g. seen in the correct habitat, Probably breeding (column 2) e.g. holding territory, visiting probable nestsite, or Confirmed breeding (column 3) e.g. seen carrying food, recent fledglings, nest with eggs or young found. The stated objective was to get as many species into column 3 as possible. The dataset records the maximum category of breeding evidence obtained for each species in each 10-km square. To make the dataset directly comparable to the second BTO/SOC/IWC Breeding Atlas 1988-91 these were converted into S – Seen (for Possibly Breeding) or B – Breeding (for Probably and Confirmed Breeding).

This datasets contains data only for the island of Ireland, but is part of the larger Britain and Ireland master dataset held by the British Trust for Ornithology at Thetford, U.K. All 10-km squares within the island of Ireland with more than a very small amount of land were visited.