Big River Watch September 2025 results: citizen science, nature connection, and action for our rivers - The Rivers Trust
From spotting pollution and wildlife to reconnecting with your local river, last month thousands of you got outside for a week full of citizen science and action for our rivers.
In September, thousands of you across the UK and Ireland pulled on your citizen science caps and joined our latest Big River Watch, our biannual invitation to everyone to step outside, spend a little time at a river, and share what you see using our free app.
This time around, an incredible 4,140 people took part and submitted 2,347 surveys. That’s an accumulative 43 days of watching, recording, and connecting with our waterways. Time well spent!
The survey was open from the 19th to the 25th of September, and your observations covered everything from pollution and wildlife to reflections on how your local river made you feel. Our brilliant technical team has looked at your data, and here is what you saw.
Wildlife highlights
Across your surveys, you shared a plethora of sightings of some iconic river creatures. Unsurprisingly, ducks once again claimed the top spot as the most commonly recorded animal. With 789 recordings, they are holding their title as Big River Watch champions for the fifth time in a row.
Although a similar number of surveys were submitted in both spring and autumn this year, nearly 100 more kingfishers were spotted this September than in May – 240 compared to 151. These iconic birds are always an exciting sight, even if often they are just visible as a quick (but unmistakable) flash of blue and orange darting over the water. Did you know that their iconic blue feathers aren't actually blue at all? In fact, they are brownish. While their orange feathers get their colour from pigmentation, the blue we see is due to a phenomenon known as 'structural colouration'. The cellular structures in their feathers scatter sunlight in a way that perfectly reflects blue wavelengths, giving them their characteristic iridescent blue.
Beyond the birds, you also recorded 624 sightings of fish, 52 of otters, 7 of beavers, 383 of dragonflies, and much more. Together, your observations provide a vital snapshot of the wildlife that depends on our waterways.
Posted On: 31/10/2025
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