Planning your visit

Planning your visit

What to consider when planning visits to your Winter Bird Survey square.

Get to know your square

Your Regional Organiser will give you the grid reference of your 1-km Winter Bird Survey square. To find the location of your square: 

  • Visit the Ordnance Survey website
  • Enter the grid reference in the ‘Locate’ box
  • The marker will appear at the bottom left corner of your square
  • Select the ‘Leisure’ button to view the National Grid of squares

Your transect route

Your Regional Organiser will provide a map of your survey route through your square. This map will show two 1-km transects divided into 10 sections, each 200m in length (numbered one to 10).

  • If your square is an existing Breeding Bird Survey square and/or was surveyed in the 2018/19 English Winter Bird Survey (EWBS), it will very likely come with a pre-mapped route. Please ensure the route you follow is the same as the one provided – consistency is essential.
  • In the unlikely event that your square does not have a pre-mapped route, please refer to the guidance on establishing a new route, and submit a route map to BTO. 

If you need to change your route, please contact your Regional Organiser in the first instance. Then you will need to follow the same procedure as for establishing a new route. Contact details for your Regional Organiser will be available from MyBTO or in BBS Online.

Access permission

You may need to ask permission to access private land on your square. A standard letter requesting access can be obtained from BTO or your Regional Organiser. Alternatively, you can download and print an access letter from our Resources page.

Equipment for your survey

On the day of the survey, you will need:

  • Field Recording Sheets and a Habitat Recording Sheet (and a clipboard if you prefer)
  • Your route map
  • Binoculars
  • A pen or pencil
  • A way of telling the time

You can download and print your recording sheets, or request paper copies by contacting winterbirds@bto.org.

When to visit

You will need to undertake up to four survey visits over the winter period:

  • Visit 1 – in late September or October
  • Visit 2 – in December
  • Visit 3 – in January
  • Visit 4 – in February

Please ensure that visits are at least three weeks apart. 

What time should you visit?

Visits can take place anytime during daylight hours. We ask that you avoid the hour immediately after dawn and the hour before dusk to reduce the risk of double-counting large flocks leaving or entering a roost. 

We appreciate that, in the far north and west of Britain, this still leaves only a narrow window of opportunity – especially with remote sites. Some flexibility can therefore be applied in those areas, with personal safety being of paramount importance.

Consistency is important, so please aim to survey at around the same time on each visit.

Surveying and the weather

Please do not survey in heavy rain, very poor visibility or strong wind. 

Survey forms and instructions

Everything you need for your survey can be downloaded from the Winter Bird Survey Recording page, and printed if necessary. You can also request paper copies of forms and instructions by emailing winterbirds@bto.org. 

We recommend that you familiarise yourself with the survey forms before you make your first visit.

Data entry

Essential reading

We acknowledge that some squares in remote or mountainous areas will simply not be possible to survey, especially in the winter months. However, for anyone considering it, we recommend reading these guides on safety in the mountains, particularly in winter:

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