Heathland Birds Survey

Survey history

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The previous population estimates made for Woodlark, Nightjar and Dartford Warbler are now almost 20 years old, based on data from surveys undertaken at a time when all three species had undergone a substantial increase in both population size and range. Both Woodlark and Dartford Warbler were at their most northerly recorded UK breeding range extents, while Nightjar was regaining ground in northern England and even into Scotland.

• In 2004, the Nightjar population was 4,600 territories (churring males).
• In 2006, Dartford Warblers numbered 3,214 territories and the Woodlark population was 3,064 territories. 

We urgently need updated population estimates to assess how breeding numbers and range for each of these species have changed throughout the UK and Channel Islands. We also need to know how birds are faring on the network of protected heathland sites that support the majority of the populations of these specialist species.

The Heathland Birds Survey has been designed to cover the current known distribution of Woodlark, Nightjars and Dartford Warblers, but also to pick up recent range expansion or contraction. The data collected will be used to calculate up-to-date population figures for key protected sites, as well as wider national and regional population estimates. The data may also help with future designations of other important sites for heathland birds. 

Focal species

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Nightjar, Woodlark and Dartford Warbler are scarce breeding species across the UK with very localised breeding distributions.

Populations of all three species are usually closely associated with heathland and similar habitats that provide bare ground, such as clear-felled and recently planted forests (Woodlark and Nightjar), cropped/mixed farmland (Woodlark), and upland moorland and coastal gorse scrub (Dartford Warbler).

Both Woodlarks and Nightjars require bare or sparsely vegetated ground to nest, while Dartford Warblers nest within dense bushes, preferring gorse and heather.

All three species are important features of protected sites, including Sites of Special Scientific Interest (SSSIs) and Special Protection Areas (SPAs), which are vulnerable to habitat change and damage such as that caused by fires and extreme weather events. Given the large proportion of Nightjar, Dartford Warbler and Woodlark populations that depend upon these habitats, it is vital that we have updated population estimates to ensure that sites are maintained appropriately and continue to support these rare species.

Take part

The Heathland Birds Survey will open for registration in January, when volunteers will be able to sign up for the survey, request survey sites for each species and access the online data entry system through the online project portal. 

• All volunteers must follow BTO’s Guidance for volunteer fieldworkers and the organisation’s Code of Conduct. 

Skills

To volunteer for the Heathland Birds Survey, you need to be able to identify Nightjar, Woodlark and Dartford Warbler by calls, song and sight. You will be surveying up to three species, using similar survey methods for each of the species. You will also need to record observations of 12 other heathland assemblage bird species: 

You also need to be familiar with plotting locations and basic habitat recording. Some experience using online data entry systems is useful. 

Time

Volunteers will make between two and four visits for each of the species during the species’ survey periods:

• Woodlark (15 February – 31 May)* – two early morning visits between sunrise and 11 a.m.
• Dartford Warbler (1 April – 30 June)* – two early morning visits between sunrise and 11 a.m.
• Nightjar (25 May – 15 July) – two evening visits covering the two-hour period after sunset, or the two hours prior to sunrise. We recommend a daytime recce visit before the survey is undertaken.

*On sites where both Woodlark and Dartford Warbler occur, volunteers will need to make three visits to cover the survey periods, recording both species on each visit.  

Volunteers will usually need to spend up to two hours per visit, in order to survey all the suitable habitat in a single 1-km survey square. However, where small amounts of habitat are present at least two squares could be covered per morning.

Location

Survey sites (1-km squares) for each species include known or recently occupied locations, including some of the larger protected sites (SSSIs and SPAs), as well as a random sample of squares containing potentially suitable habitat nearby. This combination of survey squares allows us to get good coverage of the current known distribution but also pick up recent range expansion and contraction.

Volunteers will be able to request a survey site for each species through the Heathland Birds Survey online portal when the survey opens for registration in December. 

Access permission

All observers are reminded of the need to obtain permission to cross any private land in England, Wales and Northern Ireland (observers in Scotland should adhere to the Scottish Outdoor Access Code). 

Methods

During the survey period, volunteers will need to:

• Record all observations of the three target species including sex, activity and relationships between individuals
• Record basic habitat-use information for each territorial bird observed
• Plot all observations of the three target species on the survey map provided
• Record all observations of an additional 12 ‘heathland assemblage’ species, with a count of the number of pairs/territories found in the survey square

The known likely suitable habitat will be indicated on the survey map, but volunteers should check the whole square in case of other suitable areas which need to be included.

Sign up

The Heathland Birds Survey will open for registration in January, when volunteers will be able to sign up for the survey, request survey sites for each species and access the online data entry system through the online project portal. 

• Please visit this page in January to sign up.

Partners and funders

The Heathland Birds Survey is a partnership project run by the British Trust for Ornithology (BTO) and the Royal Society for the Protection of Birds (RSPB).

It is supported by funding from Natural England.