News Archive

Here you can find an archive of all of the News items related to the Hertfordshire Bird Atlas in reverse chronological sequence.

The most recent news items can be found on the Home page.

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

July 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 16 July 2012. This includes Timed Tetrad Visit data for this season that was entered online. The winter species density map and breeding species density map show the numbers of species recorded in each tetrad and where we still have gaps.

Fieldwork for the 10km scale national atlas has now finished, although we will be continuing to collect tetrad-level records for the county atlas during the 2012 breeding season.

16 July 2012

May 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 31 May 2012. This includes Timed Tetrad Visit data for this season that was entered online. The winter species density map and breeding species density map show the numbers of species recorded in each tetrad and where we still have gaps.

Fieldwork for the 10km scale national atlas has now finished, although we will be continuing to collect tetrad-level records for the county atlas during the 2012 breeding season.

8 June 2012

March 2012 Data Refresh and Final Breeding Season Starts

This website has been refreshed to include all winter season data entered to the Bird Atlas 2007-11 website by 21 March 2012. This includes Timed Tetrad Visit data for this season that was entered online. Please send or enter any outstanding winter records as soon as possible.

Fieldwork for the fifth and final breeding season starts on 1 April. Although a few Timed Tetrad Visits reman to be completed, the focus for this season is improving the breeding status. The Breeding Season species density map and Confirmed Breeding evidence map show where the gaps are.

27 March 2012

February 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 13 February 2012. This includes Timed Tetrad Visit data for this season that was entered online. The winter species density map and breeding species density map show the numbers of species recorded in each tetrad and where we still have gaps.

Fieldwork for the 10km scale national atlas has now finished, although we will be continuing to collect tetrad-level records for the county atlas in the 2011/12 winter season and the 2012 breeding season.

18 February 2012

January 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 6 January 2012. This includes Timed Tetrad Visit data for this season that was entered online. The winter species density map and breeding species density map show the numbers of species recorded in each tetrad and where we still have gaps.

Fieldwork for the 10km scale national atlas has now finished, although we will be continuing to collect tetrad-level records for the county atlas in the 2011/12 winter season and the 2012 breeding season.

6 January 2012

Volunteers' Newsletter 6 Now Available

With winter season fieldwork starting on 1 November, the latest Volunteers' Newsletter is now available. Please take the time to read this to see what we have achieved so far and understand our priorites for this winter.

8 November 2011

October 2011 Data Refresh

This website has been refreshed to include all breeding and winter season data entered to the Bird Atlas 2007-11 website by 17 October 2011. This includes Timed Tetrad Visit data for this season that was entered online. The winter species density map and breeding species density map show the numbers of species recorded in each tetrad and where we still have gaps.

Fieldwork for the 10km scale national atlas has now finished, although we will be continuing to collect tetrad-level records for the county atlas in the 2011/12 winter season and the 2012 breeding season.

24 October 2011

August 2011 Data Refresh

This website has been refreshed to include all breeding and winter season data entered to the Bird Atlas 2007-11 website by 30 August 2011. This includes Timed Tetrad Visit data for this season that was entered online. The winter species density map and breeding species density map show the numbers of species recorded in each tetrad and where we still have gaps.

Fieldwork for the 10km scale national atlas has now finished, although we will be continuing to collect tetrad-level records for the county atlas in the 2011/12 winter season and the 2012 breeding season.

31 August 2011

June 2011 Data Refresh

New data for the breeding season has been loaded to this website. The maps may be accessed via the New Breeding Atlas map index pages. Alternatively, you can access the data by tetrad by clicking through the status maps.

This refresh includes all data entered to the Bird Atlas 2007-11 website by 15 June 2010.

It is good to see over 800 extra Confirmed Breeding records added or upgraded in the past month. However, there are still 2800 species records with no breeding assessment noted, and which are not shown here. Please remember that a bird in song (code S) or merely present in suitable habitat (code H) is classed Possible Breeding.

17 June 2011

May 2011 Data Refresh

New data for the breeding season has been loaded to this website. The maps may be accessed via the New Breeding Atlas map index pages. Alternatively, you can access the data by tetrad by clicking through the status maps.

This refresh includes all data entered to the Bird Atlas 2007-11 website by 3 May 2010, including TTV data that was entered online.

03 May 2011

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

Volunteers' Newsletter 7 Now Available

With breeding season fieldwork starting on 1 April, the latest Volunteers' Newsletter is now available. Please take the time to read this to see what we have achieved so far and understand our priorites for this season.

2 April 2011

March 2011 Data Refresh and Fourth Breeding Season Starts

This website has been refreshed to include all breeding and winter season data entered to the Bird Atlas 2007-11 website by 14 March 2011. This includes Timed Tetrad Visit data for this season that was entered online. The winter species density map and breeding species density map show the numbers of species recorded in each tetrad and where we still have gaps.

Fieldwork for the fourth breeding season starts on 1 April, and this will be the final year of the national atlas. The focus for this season is on completing the outstanding timed tetrad visits, filling the gaps in the coverage map. If you can travel to some of the less well covered parts of the county to carry out Timed Tetrad Visits, your help would be most welcome. Alternatively, please examine the species lists for tetrads where you carried out TTVs in previous years, and seek to extend the species list or improve the breeding status that has been recorded.

16 March 2011

February 2011 Data Refresh

This website has been refreshed to include all winter season data entered to the Bird Atlas 2007-11 website by 14 February 2011. This includes Timed Tetrad Visit data for this season that was entered online.

The aim before the end of the month is to finish the winter Timed Tetrad Visits, although any work to fill in missing species would be most welcome. The winter species density map shows the tetrads where fewer species have been recorded.

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

14 February 2011

January 2011 Data Refresh

This website has been refreshed to include all winter season data entered to the Bird Atlas 2007-11 website by 17 January 2011. This includes Timed Tetrad Visit data for this season that was entered online.

The aim before the end of February is to finish the winter Timed Tetrad Visits, although any work to fill in missing species would be most welcome. The winter species density map shows the tetrads where fewer species have been recorded.

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

17 January 2011

December 2010 Data Refresh

This website has been refreshed to include all winter season data entered to the Bird Atlas 2007-11 website by 14 December 2010. This includes Timed Tetrad Visit data for this season that was entered online.

Almost 23,500 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 is showing good coverage.

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

15 December 2010

Volunteers' Newsletter 6 Now Available

With winter season fieldwork starting on 1 November, the latest Volunteers' Newsletter is now available. Please take the time to read this to see what we have achieved so far and understand our priorites for this winter.

26 October 2010

October 2010 Data Refresh and Website Enhancements

This website has been refreshed to include all breeding and winter season data entered to the Bird Atlas 2007-11 website by 8 October 2010. The maps may be accessed via the New Winter Atlas map index page, the New Breeding Atlas map index page, or by tetrad by clicking through the status maps.

To help target missing species the tetrad lists have been enhanced to indicate species which are missing but have been located in four or more adjacent tetrads. These are indicated by the four-way arrow symbol Absent but present in 4 adjacent tetrads.

Fieldwork for the winter season restarts on 1 November, so please use this winter to complete any outstanding Timed Tetrad Visits and try to add to the species lists for your tetrad(s) between then and 28 February. If you have done all you can in your existing tetrad(s), please consider taking on a new square - check the tetrad allocation map for those where counts are still needed.

15 October 2010

August 2010 Data Refresh

This website has been refreshed to include all breeding season data entered to the Bird Atlas 2007-11 website by 6 August 2010. The maps may be accessed via the New Breeding Atlas map index pages, or by tetrad by clicking through the status maps.

Even though the survey period for Timed Tetrad Visites (TTVs) closed on 31 July, records which improve the breeding status (especially proven breeding records) are still welcome during August and will contribute to the county atlas. Please enter these as Roving Records at the Bird Atlas 2007-11 website.

8 August 2010

June 2010 Data Refresh

This website has been refreshed to include all breeding season data entered to the Bird Atlas 2007-11 website by 18 June 2009, including TTV data that was entered online.

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

21 June 2010

May 2010 Data Refresh

New data for both the winter and breeding seasons has been loaded to this website. The maps may be accessed via the New Winter Atlas map index or New Breeding Atlas map index pages. Alternatively, you can access the data by tetrad by clicking through the status maps.

This refresh includes all data entered to the Bird Atlas 2007-11 website by 9 May 2010, including TTV data that was entered online.

10 May 2010

March 2010 Data Refresh and Third Breeding Season Starts

This website has been refreshed to include all winter season data entered to the Bird Atlas 2007-11 website by 29 March 2010. This includes Timed Tetrad Visit data for this season that was entered online. The winter species density map shows the numbers of species recorded in each tetrad and where we still have gaps.

Fieldwork for the third breeding season starts on 1 April, and the focus for this year is on completing tetrad species lists and improving the breeding status in tetrads where you carried out TTVs in 2008 or 2009. We would also like more early morning or dusk visits this spring, to fill the gaps for nocturnal species; owls, Woodcock and, although unlikely, Nightjar.

The March 2010 Volunteers' Newsletter gives more details and some hints on finding breeding evidence. Previous issues of the Newsletter are available on the Resources page.

29 March 2010

Extended Breeding Season Data Added

This website has been refreshed to include all breeding season data entered to the Bird Atlas 2007-11 website by 24 February 2010.

The breeding season maps and tetrad lists have also been enhanced to include Confirmed breeding records from outside of the main breeding season fieldwork period (April-July). These are indicated on the maps and lists with a white plus-sign inside the large red dot Confirmed breeding outside Apr-Jul. This has filled in some gaps for late-breeding species.

The breeding species density map shows the numbers of species recorded in each tetrad and where we still have gaps.

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

27 February 2010

February 2010 Data Refresh

This website has been refreshed to include all winter season data entered to the Bird Atlas 2007-11 website by 16 February 2010. This includes Timed Tetrad Visit data for this season that was entered online.

Almost 22,000 unique species/tetrad records have been submitted for Hertfordshire tetrads and we are now starting to fill-in the out-lying parts of the county, the winter species density map shows the numbers of species recorded in each tetrad and where we still have gaps.

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

17 February 2010

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

August 2009 Data Refresh

This website has been refreshed to include all breeding season data entered to the Bird Atlas 2007-11 website by 18 August 2009, including TTV data that was entered online.

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

21 August 2009

June 2009 Data Refresh

All the paper records for the 2008/09 winter season have now been loaded into the Bird Atlas 2007-11 database at BTO headquarters and new data for both the winter and breeding seasons has been transferred to this website. The maps may be accessed via the New Winter Atlas map index or New Breeding Atlas map index pages. Alternatively, you can access the data by tetrad by clicking through the status maps.

This refresh also includes all data entered to the Bird Atlas 2007-11 website by 18 June 2009, including TTV data that was entered online.

23 June 2009

May 2009 Data Refresh

New data for both the winter and breeding seasons has been loaded to this website. The maps may be accessed via the New Winter Atlas map index or New Breeding Atlas map index pages. Alternatively, you can access the data by tetrad by clicking through the status maps.

This refresh includes all data entered to the Bird Atlas 2007-11 website by 18 May 2009, including TTV data that was entered online.

21 May 2009

March 2009 Data Refresh

New data for both the winter and breeding seasons has been loaded to this website. The maps may be accessed via the New Winter Atlas map index or New Breeding Atlas map index pages. Alternatively, you can access the data by tetrad by clicking through the status maps.

This refresh includes all data entered to the Bird Atlas 2007-11 website by 31 Mar 2009, including TTV data that was entered online, and most of the paper forms.

6 April 2009

New Breeding Season Begins

Fieldwork for the second breeding season of this four-year project starts on 1 April 2009. This will build on the excellent achievements in the 2008 season when 182 paired Timed Tetrad Visits were completed and supplemental Roving Records were collected from a further 259 tetrads.

The priority for this season should be completion of outstanding Timed Tetrad Visits and extra field visits to the allocated tetrads to improve the breeding status. Multiple visits will be needed to cover different species which breed at different times as the season progresses.

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

31 March 2009

More Winter 2009 TTV Data and Breeding Season Record Cards Now Available

New data for the winter season is now available on this website via the New Winter Atlas map index page. Alternatively, you can access the data by tetrad by clicking through the Winter Season Status Map.

This refresh includes all data entered to the Bird Atlas 2007-11 website by 24 Feb 2009, including TTV data that was entered online. In all this comprises 7268 unique species registrations from Timed Tetrad Visits in 309 tetrads and a further 7823 unique Roving Records from 450 tetrads.

The breeding season maps have also been refreshed to include all a small number of late records entered online since 13 Jan 2009.

In preparation for the second year of Breeding Season fieldwork, customised recording cards are now available from the tetrad pages.

10 March 2009

Early Winter 2009 TTV Data Now Available

New data for the winter season is now available on this website via the New Winter Atlas map index page. Alternatively, you can access the data by tetrad by clicking through the Winter Season Status Map.

This refresh includes all data entered to the Bird Atlas 2007-11 website by 13 Jan 2009, including any Nov/Dec 2008 TTV data that was entered online. In all this comprises 7152 unique species registrations from Timed Tetrad Visits in 298 tetrads and a further 7126 unique Roving Records from 435 tetrads.

The breeding season maps have also been refreshed to include all a small number of late records entered online between 26 Nov 2008 and 13 Jan 2009, but some paper TTV forms remain to be entered. After eliminating duplicates, this comprises 4533 possible breeding records, 3346 probable breeding records and 3528 confirmed breeding records.

These results are provisional and some records may subsequently be removed if they are found to be mis-identifications or data entry errors.

18 January 2009

Winter and Breeding Season Data Updated

New data for the winter and breeding seasons are now available on this website via the New Winter Atlas map index and New Breeding Atlas map index pages. Alternatively, you can access the data by tetrad by clicking through the Winter Season Status Map or Breeding Season Status Map.

The winter maps include all data entered to the Bird Atlas 2007-11 website by 14 Nov 2008. This comprises 5763 unique species registrations from Timed Tetrad Visits in 215 tetrads and 6259 unique Roving Records from 386 tetrads.

The breeding season maps include data entered online before 26 Nov 2008, paper TTV forms received by the BTO by mid-September and paper Roving Records forms received by mid-October. After eliminating duplicates, this comprises 4503 possible breeding records, 3350 probable breeding records and 3497 confirmed breeding records.

These results are provisional and some records may subsequently be removed if they are found to be mis-identifications or data entry errors.

3 December 2008

First Breeding Season Atlas Data Now Online

The first provisional maps of Hertfordshire breeding season data are now available on this website via the New Breeding Atlas map index. All breeding season atlas results entered online on the Bird Atlas 2007-11 website by 4 Sep 2008 are included. After eliminating duplicates, this comprises 4315 possible breeding records, 3290 probable breeding records and 3167 confirmed breeding records. In all, records of at least possible breeding have been received for 422 of the 491 Hertfordshire tetrads.

Care has been taken to adhere to the national guidelines for rare breeding birds, which is extended and reflected in a local policy. So, the maps for several species show records only at the 10km square level, and for a very few species no maps are shown at all. We hope that this policy will encourage you to submit your sightings in the knowledge that they will be dealt with appropriately.

As with the winter data, these results are provisional and some records may subsequently be removed if they are found to be mis-identifications or data entry errors.

Thanks are extended to everyone who has contributed so far. This is a fantastic start to this four-year project.

19 October 2008

Customised Recording Forms Now Available

In preparation for the second season of winter fieldwork, new functionality has been added to this website to allow you to print a custiomised recording form for any tetrad. This has the recording date shaded out for those species which have already been recorded, allowing you to focus on finding the remaining species. For example, despite an excellent species list, the Great Amwell tetrad (TL31R) still has a few missing species as shown on its Recording Card.

14 October 2008

First Winter Season Atlas Data Now Online

The winter season maps now have been updated with the data from the 2007-08 season of fieldwork and patterns are already starting to emerge. For example, see how widely Stonechat was recorded, when compared to the 10km distribution in 1981/2-1983/4.

All winter atlas results entered online on the Bird Atlas 2007-11 website or submitted on paper and manually entered by 27 Jun 2008 are included.

This comprises information from Timed Tetrad Visits in 214 tetrads and Roving Records from a futher 197 tetrads. A number of observers have been attributing their BirdTrack records to an individual tetrad, and this has provided another valuable source of information, with records from 93 tetrads.

Please note that these results are provisional and some records may subsequently be removed if they are found to be mis-identifications or data entry errors. This data validation process is awaiting further development work on the Bird Atlas 2007-11 website.

Thanks to everyone who has contributed so far. A total of 38,337 individual records from 413 tetrads are already helping to further our knowledge of winter bird distributions in Hertfordshire.

1 October 2008

Breeding Season Coverage Map Added

As the breeding season gets underway and fieldwork for this part of the project starts to accumulate breeding evidence, you can keep track of progress on the breeding season coverage map. This reflects Timed Tetrads Visits and Roving Records submitted online to the Bird Atlas 2007-11 website.

Please note where there are gaps in coverage and consider visiting those less-frequented parts of the county and submitting Roving Records.

It will take a while before the first results for the breeding season are added to this website, as we are heavily dependent upon web development resources at the BTO headquarters to provide the data transfer functionality.

29 April 2008

More Winter Atlas Data Now Available

A second batch of records for the new winter atlas has now been loaded to this website. The First Winter Atlas maps now include all data submitted online to the Bird Atlas 2007-11 website up until 29 Feb 2008. Records from Timed Tetrad Visits in 185 tetrads and Roving Records from a futher 204 tetrads are included. These maps do not yet include data received on paper forms, although the coverage map does reflect those submitted via the Hertfordshire organiser.

A number of observers have been attributing their BirdTrack records to an individual tetrad, and this has provided another valuable source of information, with records from 76 tetrads.

Please note that these results are provisional and some records may subsequently be removed if they are found to be mis-identifications or data entry errors. This data validation process will not take place until all the first winter data have been received, including the paper records.

Thanks to everyone who has contributed so far. A total of 12892 individual records from 394 tetrads are already helping to further our knowledge of winter bird distributions in Hertfordshire.

28 April 2008

2007 BirdTrack Data Added

Up until 7 February 2008, 94 Hertfordshire BirdTrack sites have been assigned to an individual tetrad. Records from these sites have now been added to the existing Timed Tetrad Visit and Roving Record data. On the New Winter Atlas maps on this site we now have TTV data for 159 tetrads, Roving Records for a further 153 tetrads and BirdTrack data for a further 7 tetrads.

Please note that these are provisional results only, and the records have not been through any verification process. Excluded at present are the results from a large number of Timed Tetrad Visits, which have been collected on paper forms.

19 February 2008

Initial Winter Atlas Data Now Available

The first batch of records for the new winter atlas has now been loaded to this website and some interesting patterns are starting to emerge. This is a fantastic response just half way through the first of four winter seasons. The new provisional maps can be explored from the New Winter Atlas species index.

Please note that these results are provisional and some records may subsequently be removed if they are found to be mis-identifications or data entry errors. This data validation process will not take place until all the first winter data have been received.

These preliminary results represent all data submitted online to the Bird Atlas 2007-11 website up until 8 Jan 2008. Records from Timed Tetrad Visits in 180 tetrads and Roving Records from another 141 are included. It does not include such data still on paper forms.

A considerable number of observers have been attributing BirdTrack records to an individual tetrad, and a batch of these will be added shortly.

5 February 2008

Atlas Fieldwork Has Started

After months of preparation, planning and publicity, fieldwork for the Hertfordshire Bird Atlas and Bird Atlas 2007-11 has started. Over 200 of the 491 Hertfordshire tetrads already have volunteers assigned. and except in the most rural areas of the county we also have sufficient Timed Tetrad Visits planned to meet our commitment to gather abundance data for the national atlas.

The Bird Atlas 2007-11 website now gives you the ability to enter Timed Tetrad Visit counts and Roving Records online. As long as the Roving Records are assigned to a tetrad, they will also be used in the Hertfordshire Bird Atlas. In BirdTrack there is a new facility to register a tetrad as a site, making it quick and easy way for volunteers to enter a long list of species for a tetrad.

Even if you have not already signed up, it is not too late. To volunteer for Timed Tetrad Visits, please take a look at the Bird Atlas 2007-11 website or if you would prefer just to accumulate a species list for a particular 2km x 2km square tetrad, contact your local 10km square Co-ordinator whose details are shown on the Contacts page.

1 November 2007

New Informational Maps Added to Website

To see how coverage of the county is progressing as volunteers sign up to this project, an atlas coverage map has been developed and is being updated regularly. Also, to show how the Hertfordshire Bird Atlas intereacts with adjacent counties, most of which are running their own tetrad-scale atlases, a County Tetrad Map has been produced. Both of these maps are available from the Resources page.

29 October 2007

Instructions and Recording Forms Now Available

As the start date of 1st November 2007 approaches, Instructions and Recording Forms for the winter season have now been added to the Resources page.

29 September 2007

First Winter Atlas Data Added to Website

For three winters between 1981/82 and 1983/84, an atlas of wintering birds in Britain and Ireland was undertaken as a collaboration between The British Trust for Ornithology and the Irish Wildbird Conservancy. Produced as a companion to the 1967-72 breeding atlas, the results were published in The Atlas of Wintering Birds in Britain and Ireland.

The results of the survey work in the 18 10km squares that form the Hertfordshire BTO region have now been added to this website. Read more

The use of timed visits to each of 3,761 10km squares across Britain and Ireland allowed the calculation of measures of relative abundance. The abundance threshold vary widely between species, an are based on a 50% : 30% : 20% split between the low, medium and high categories, using data from all regions. On this website, these thresholds are respresented by three different shades of blue.

9 July 2007

More 10km Square Co-ordinators Appointed

To help organise fieldwork across the county, there will be a network 10km Square Co-ordinators with local knowledge of their area. I am pleased to report some new appointments.

The following have kindly agreed top help organise atlas fieldwork in their respective areas :

Full contact details are available on the Contact Us page.

I am still seeking a co-ordinator to help with TL30 (Cheshunt and Hoddesdon).

21 June 2007

New 10km Square Co-ordinators Appointed

To help organise fieldwork across the county, there will be a network 10km Square Co-ordinators with local knowledge of their area. I am pleased to report the some new appointments.

The following have kindly agreed top help organise atlas fieldwork in their respective areas :

Full contact details are available on the Contact Us page.

I am still seeking co-ordinators to help with TQ09 (Rickmansworth), TL00 (Hemel Hempstead) and TL22 (Stevenage).

28 January 2007