The BOS is conducting a survey of Yellowhammers in the first 2 weeks of July 2018 to determine their population abundance, distribution and breeding status. We will be surveying 1km squares in the BOS survey area (see BOS Map).

We are inviting BOS members and other birdwatchers to assist in this survey, which will only take an hour to complete. We provide full instructions and a simple form to record your results on. We will analyse the results to determine the current status of Yellowhammers and aim to publish the results on our website on this page.


If you would like to take part, please see the map below and select a 1km square to survey, making a note of the OS grid reference. Then send then an email to the BOS bird recorder (Mike Curnow) with the number of the square you would like to survey (This email address is being protected from spambots. You need JavaScript enabled to view it.). The recorder will confirm your request and send a survey form for you to complete.


Yellowhammers are one of our common and widespread resident birds of the farmed countryside.  Sadly, their numbers have declined over recent decades and they are Red-listed in the latest “Birds of Conservation Concern 4”.  We are able to monitor their changing fortunes though our annual surveys (Winter and Summer random square surveys and the BTO’s Breeding Bird Survey (BBS)). However, we are lacking more detailed information on their distribution and density across the BOS study area, therefore we are carrying out a specific Yellowhammer Survey during 2018.

In England, Yellowhammers have declined by 26% from 1993 to 2015, and 33% locally, based on a linear trend from the BOS summer breeding surveys. The situation is even worse for the period 1977-2015, with a 62% national and 76% local decline in abundance based on our Winter Random Square Survey. Thus, it appears that Yellowhammers in the BOS area have been just as affected by environmental changes as those across England, hence our interest in performing a more detailed study.

Male Yellowhammers are easy to locate and identify during the breeding season.  Their song – described as “a little bit of bread and no cheese” is easily recognisable with a bit of practise, and their canary yellow head plumage is highly distinctive.  They also have a long breeding season, extending from April through to August, during which the male sings quite regularly.  This means the Yellowhammer is a bird we can survey relatively late into the breeding season, well after many other birds have completed breeding. Our SRSS breeding surveys show that Yellowhammers breed right across the BOS (in over 90% of survey squares), so there is a very good chance of finding them on this survey.

Survey Method

Our aim is to obtain the best estimates of the number of breeding pairs of Yellowhammers per square km and a total population count. This is not going to be an exact science but should give a good approximation to the numbers present.

We will carry out the survey in the first two weeks of July, each survey will take one hour and cover a 1km x 1km square.  The survey should take place within the period 06:00 – 11:00 or 17:00 – 20:00, thus avoiding the “lull” in activity around the middle of the day. Each survey square is chosen randomly from those squares we know have reasonable access for fieldwork and are potentially suitable habitat for Yellowhammers. You only to survey the square once.

Plan to walk a route around your square in advance, making use of rights of way, to determine where the best places are for potential breeding birds. Listen out for the Yellowhammer’s song and scan hedgerows and trees to locate the singing male.  You will probably locate most birds by song, but keep using your eyes and ears, and note down all yellowhammers seen.

All you need to record is the total number of Yellowhammers seen in your given square and counts of the birds categorised by activity: Singing males, adult carrying food or number of adult pairs seen. We will use the numbers in these categories to try and assess the number of potential breeding pairs. We also ask you to make an estimate of the percentage of the square you managed to survey.

Please record on the survey form the following information:

  • Your Name and the date you performed the survey
  • The survey square number (OS Grid Reference)
  • The total number of Yellowhammers you have seen
  • Number of Singing Males – exclude alarm or other calls. Singing males are usually perched on the top of a tree, bush or hedge.
  • Number of Adult Pairs seen – e.g. 3 pairs = 6 birds in total
  • Number of Adults carrying food

Please try and avoid double counting, i.e. record a bird in only one of the 3 categories: singing, pair or carrying food. We do not require you to go hunting for nests and the general advice is to try and not to disturb the birds on your survey.

Sample Survey Form Results

Observer Name

Susan Bunting

Survey Square Number (4-digit Grid Reference)


Date and time of survey

08:30-9:30, 6 July 2018

Total number of Yellowhammers seen


Number of Singing Males


Number of Adult Pairs Seen


Number of Adults carrying food


Estimate of % of square covered


How to Request a Survey Square

The map below shows the BOS survey area and the survey squares that are available with their 1km OS grid reference (the prefix for which is “SP”). This map will be updated regularly as squares are allocated, so only available squares are listed.

To request a square, please send an email to the BOS recorder (Mike Curnow) at This email address is being protected from spambots. You need JavaScript enabled to view it., specifying the square number of your 1st and 2nd preference. We will then send a confirmation email along with the survey form to complete.

Please note that registration closes on 24th June.

Thank you for taking part in this survey.

Yellowhammer Survey Available Squares 2018 07 02

Note: the numbers next to each diamond are the Ordnance Survey 4-digit grid references with the OS 100km square “SP”, e.g. 3434 means “SP3424”. The 1st 2 digits are the easting (along the bottom of the map) and the 2nd 2 digits are the northing (up the map). Use an Ordnance Survey 1:50K or 1:25K map to find out further details on the square or use this link: – enter the grid reference (e.g. SP3424) to zoom the map to that location. Use the map zoom controls to zoom out to see the Ordnance Survey map.

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