Have you been on a coastal walk and noticed a large, square structure floating in the water?
It might look a bit out of place — but it’s actually a lifeline for terns, some of the Solent’s furthest-travelling summer visitors.
From April to August, the Solent coastline becomes a seasonal home for migratory birds that travel thousands of miles from Western and Southern Africa. There are three tern species you’re more likely to see: the Sandwich tern, the common tern, and the little tern.
These birds have travelled all this way for one thing – breeding. Unlike other birds that build nests in trees or shrubs, terns prefer a minimalist approach. They lay their eggs directly on shingle beaches in shallow depressions called “scrapes”: just a bowl or dip in the stones which provide camouflage from predators.
But this nesting strategy comes with a downside. Over the past two decades, rising sea levels, high spring tides and storm surges have drastically reduced the availability of natural nesting sites. Added to this, since scrape nests are so effective at camouflaging eggs, it’s hard to spot them and keep an appropriate distance when we’re visiting the coast, and that means they can easily get disturbed. The result? A worrying decline in tern populations around the Solent.
Tern rafts
To help turn the tide, conservationists have introduced an innovative solution: ‘tern rafts’. These floating platforms mimic the terns’ natural nesting habitat and provide a safe, relatively predator-free space for them to breed.
Above: Chichester Harbour Conservancy’s tern raft at Thorney Deeps
You can spot these rafts in several locations across the Solent, including: Thorney Deeps in Chichester Harbour; the Oysterbeds and Farlington Marshes in Langstone Harbour; Hook Links near Warsash; and in Keyhaven River near Hurst Spit.
So how do tern rafts work?
Each raft is carefully designed to support successful breeding:
- A floating platform – which keeps the nest above rising tides and storm surges
- A shingle or gravel layer – which mimics the natural beach habitat for nesting
- A perimeter barrier – to prevent chicks from falling overboard
- An anchoring system – to keep the raft stable and in place.
These features help protect the terns from flooding, disturbance, and land-based predators—giving them a much-needed boost during the breeding season.
Why focus on terns?
Common terns often nest alongside black-headed gulls, which, despite their noisy nature, offer excellent protection from land-based and aerial predators.
However gulls tend to nest earlier in the season, and by the time terns arrive, the gulls are often in the midst of incubating their eggs, with prime nesting spots already taken. This can make for a tricky time for terns as they attempt to establish territory.
Combined with a reduction in natural habitats, common terns risk being pushed away from nesting habitats altogether.
In some locations, like the Oysterbeds on Hayling Island, the RSPB choose to keep the rafts covered until the black-headed gulls have started nesting and settled elsewhere. This gives the terns a fair shot at grabbing some key real estate once the covers are removed.
Watch the action live
Want to see the terns in action? You can!
Chichester Harbour Conservancy’s Tern TV, which started in 2024, offers a live look at one of the rafts. Since the rafts were introduced in 2019, they have successfully fledged between 20 and 55 chicks each year, with the exception of 2023, when avian flu impacted many bird populations.
Right now, the raft is bustling with common tern parents feeding their chicks a steady diet of fish: mainly sandeels. It’s a fascinating glimpse into the lives of these long-distance travellers before they head back to Africa at the end of summer.
And, if you haven’t quite had your tern livecam fix, you can also follow along with Seabird TV, hosted by the Solent Seascapes Project and RSPB’s Life on the Edge. Set out in the islands of Langstone harbour, it’s a fantastic opportunity to get a glimpse into the lives of our summer visitors, from Sandwich terns to Mediterranean gulls.
From left to the right: the common tern, little tern and Sandwich tern
