New Hertfordshire Bird Atlas

Starting in November 2007 and running for four years, the Herts Bird Club will be collecting data to produce a new county bird atlas, surveying all 491 tetrads (2km x 2km squares) that include part of the county. This project will run alongside, and use the same methods as, Bird Atlas 2007-11 - the British Trust for Ornithology / BirdWatch Ireland / Scottish Ornithologists Club atlas of the birds of the whole of Britain and Ireland. Read more

The populations and distributions of Britain's birds are in a constant state of flux, as changes in the habitat and climate impact all aspects of their lifecycle. Only by monitoring where, when and in what numbers are our birds using the variety of habitats and resources within the county can we hope to understand these impacts.

Annual monitoring schemes, such as the BTO/RSPB/JNCC Breeding Bird Survey (BBS) operate by counting birds in randomly selected squares and provide yearly measures of population change. At the county level this gives only a broad indication of the changes in a relatively small number of species. Atlas projects complement the BBS by providing comprehensive information on the distribution of birds, covering far more squares than BBS.

The new Hertfordshire atlas will comprise the first systematic assessment of the distribution of birds in the county in winter and the third breeding season atlas, updating the distribution maps for 1988-92 published in The Breeding Birds of Hertfordshire and reproduced in interactive format on this website.

October 2012 Data Refresh

This website has been refreshed to include all breeding and winter season data entered to the Bird Atlas 2007-11 website by 3 October 2012. This includes Timed Tetrad Visit data and BirdTrack records that were attributed to a tetrad. The winter species density map and breeding species density map show the numbers of species recorded in each tetrad.

Fieldwork for the Hertfordshire Bird Atlas has now finished, and any remaining records should be submitted as soon as possible.

17 October 2012

Rare Species Policy Revised

At a recent meeting of the Herts Bird Club Scientific Committee, it was decided to relax some of the mapping restrictions that had been applied when this website was first launched. There was concern that by restricting maps to the 10km scale, we may be losing tetrad records for some species. The list of species that are mapped at the 10km level, or not at all, was reviewed and the risk of revealing the tetrad-level breeding status was assessed. Consequently, the breeding season maps for the following species now show records at the tetrad level: Gadwall, Shoveler, Pochard, Little Egret, Red Kite, Barn Owl, Kingfisher, Lesser Spotted Woodpecker and Cetti's Warbler.

29 April 2011