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.

December 2009 Data Refresh

This website has been refreshed to include all winter and breeding season data entered to the Bird Atlas 2007-11 website by 21 December 2009. This includes Timed Tetrad Visit data for this season that was entered online.

As part of an initiative to integrate data from all BTO work, this now includes ringing data, which can be particularly useful in establishing proof of breeding.

Over 20,000 unique species/tetrad records have been submitted for Hertfordshire tetrads and although there is still work to do in the out-lying parts of the county, the winter species density map clearly shows the hot spots at the major wetland sites.

The winter species maps may be accessed via the New Winter Atlas map index pages, or by tetrad by clicking through the status maps.

22 December 2009

Third Winter Season now underway

Fieldwork for the third winter season of this four-year project started on 1 November 2009. We are making excellent progresss, with both winter Timed Tetrad Visits (TTVs) having been completed in 318 of the 491 tetrads that we are surveying for this project. The priority for this winter is to complete the TTVs in tetrads where only one of the paired visits has been done, and to carry out both TTVs in the remaining Hertfordshire tetrads. Observers are also being encouraged to visit their tetrads in the evening to listen for owls, as these seem currently to be under-recorded.

To address the gaps in some of the less well watched areas of the county, two "atlas days" have been announced, when we will aim to share transport to get a batch of adjacent tetrads surveyed.

  • Sunday 22 November Markyate area
  • Sunday 13 December North-east Herts

Please contact if you are able to help on one of these days and will be available to carry out the late visit on a date to be arranged in January or February.

The October 2009 newsletter is available to download from the Resources page.

2 November 2009