GARDEN COUNTS
Birds at the window
The RSPB calls Big Garden Birdwatch the world's largest garden wildlife survey. Because it runs every year, trends can be tracked over time.
Find your level
HOW VOLUNTEER DATA IS CHECKED
Anyone can add
a data point.
Volunteers have gathered UK wildlife records for decades.
Citizen science, also called community or participatory science, means members of the public contributing to research. Researchers cannot gather data across a whole country, every year, on their own. Volunteers can, and checks make their records usable.
COUNT IT and send it in
Find your level- Same method every time
- Many people, wide areas
- Records get checked
- Small counts, big trends
THE SHORT ANSWER
Many observers,
one method.
A single count tells you little.
Thousands, repeated every year, show a trend.
SEASHORE SURVEYS
Seaweed and kelp
The Natural History Museum asks volunteers to record seaweeds on the shore to track environmental change, and says no special skills are needed.
How to start
SKILLED SURVEYS
Walk a square
Breeding Bird Survey volunteers walk two 1-km lines across a randomly selected square each spring, counting every bird seen or heard.
See the numbers
FOUR WAYS TO START
Begin small,
stay consistent.
Most projects explain what to do. These are the habits the organisers' guidance keeps coming back to.
Pick a project that fits
Some need no special skills; others, like the Breeding Bird Survey, need you to identify birds by sight, song and call.
Follow the method exactly
Surveys such as the BBS set the lines to walk and the visit windows, so every volunteer records the same way.
Send records in
Paper forms and online portals both count. Data only helps once it reaches the scheme.
Expect your records to be checked
Automated checks and expert verification are used to make sure volunteer records are accurate.
TWO NUMBERS WORTH KNOWING
Wide nets,
long records.
One figure on how many people take part,
one on how much a skilled survey covers.
650,000+
People who took part in Big Garden Birdwatch 2026
Together they counted 9.4 million birds. The RSPB says people have spent 13.4 million hours counting birds for the survey since 1979.
PARTICIPATION · RSPB 2026
119
Bird species with Breeding Bird Survey trends
Run by BTO, JNCC and the RSPB, the survey produces population trends for 119 bird and nine mammal species, thanks to almost 3,000 volunteers.
COVERAGE · BTO
The Biological Records Centre says volunteer observers for UK biodiversity surveillance were estimated in 2007 to contribute time in-kind worth more than £20 million.
A QUICK CHECK
How much can
you give?
Pick a kind of project to see what it asks of volunteers. The bar shows how much skill and time it needs, from the organisers' own descriptions.
Based on RSPB, Natural History Museum, BTO and Biological Records Centre pages. General information.
WHY DATA QUALITY MATTERS
Checked before
it is trusted.
The Biological Records Centre says data quality is often a major challenge for citizen science. Automated checks developed by schemes and societies, coupled with expert verification, play a critical role in ensuring biological records are accurate.
Design helps too. The Breeding Bird Survey uses randomly selected 1-km squares, and the Big Garden Birdwatch runs every year so that trends, not single counts, carry the weight.
QUESTIONS PEOPLE ASK
Volunteer data questions
What is citizen science?
The Natural History Museum describes it as a collaborative approach where the public actively contributes to scientific research. It is also called community science or participatory science.
Do I need special skills?
It depends on the project. The Museum says anyone can take part in its projects without special training, while the Breeding Bird Survey asks volunteers to identify birds by sight, song and call.
Is volunteer data reliable enough for science?
Schemes use automated checks plus expert verification. The Biological Records Centre says these play a critical role in ensuring records are accurate.
How long has garden bird counting run?
The RSPB says 13.4 million hours have been spent counting birds for Big Garden Birdwatch since 1979.
What has citizen science found?
One example: the Breeding Bird Survey's 2025 report found Stock Dove up by over 40% in 10 years, while Collared Dove has fallen by around 40% since 2005.
How are wildlife records sent from an app checked?
The Biological Records Centre says verification and validation methods within iRecord provide quality assurance and the onward flow of data. Apps draw a lot of records: the UK Ladybird Survey app brought in more than 9,000 in its first year, and the iRecord Butterflies app more than 4,000 within a month of release.
Why does the Breeding Bird Survey use set squares and lines?
So every volunteer counts the same way. Almost 3,000 volunteers each survey a randomly selected 1-km square, making a recce and two early-morning visits each spring and counting every bird seen or heard along two 1-km lines. That shared method is what lets the BTO, JNCC and RSPB produce population trends for 119 bird species.
Has a citizen science project changed what scientists know?
One example from the Biological Records Centre: Conker Tree Science engaged over 8,000 people to report the horse chestnut leafminer moth. The project improved understanding of how the moth spread, of the parasitoids that attack it and of the value of citizen science itself.
Sources
- RSPB: Big Garden Birdwatch results
- BTO: Breeding Bird Survey
- Natural History Museum: Community science
- Biological Records Centre (UKCEH): Citizen Science
Updated