One of the three Common Tern chicks ringed in 2004. © FoTR
Common Terns (Sterna hirundo) are a regular sight in the summer months, from around mid-April, after they return from their winter quarters on the western seaboard of the Iberian Peninsula and down through Africa. They can be seen plunge diving for small fish, which makes up most of their diet.
Terns commonly nest on beaches, but because of a lack of suitable nesting sites, they didn't breed locally. After FoTR was set up in 1993, a 'home made' tern raft was constructed and floated out on to Wilstone, to provide these inland birds with an artificial beach, which had the added benefit of keeping the birds’ eggs safe from a number of predators including foxes, mink and magpies. Rafts had also been put out at College Lake and Common Terns began breeding. Terns first bred successfully on the Wilstone raft in 1994 and one chick was ringed by the local Ringing Team. Eventually this old raft sprang a leak and the terns had stopped using it by 1998, although they didn't breed on it again.
In 2004 two new rafts were launched. The new rafts were built by some of our members, together with the Herts & Middlesex Wildlife Trust and volunteers, and were positioned in the south west corner. A pair of Common Terns took to the new rafts very quickly and successfully nested that year; three chicks were ringed in May. A shelter was also placed on the raft as protection against predators. But again, they didn't breed on it after that year.
One of the three Common Tern chicks ringed in 2004. © FoTR
Two of the rafts were repaired in 2006 (see more here), and in late April 2007 Herts and Middlesex Wildlife Trust (HMWT) launched two new rafts. The Trust worked in partnership with Venables, a local Hertfordshire company, to design and build the rafts. They are a pioneering design, using plastic modular floats, which fit together like a jigsaw, to create a three metre square floating platform. In addition, outrigger boards were added to prevent predators like mink from getting onto the rafts. Foothigh weld-mesh fences around the raft will prevent the tern chicks from falling off the rafts. A thick layer of ‘Gucci-gravel’ – a specially designed mix of gravels - was spread over the top of the rafts to provide the perfect conditions for the terns to breed. Finally shelters, consisting of roofing ridge tiles, were placed on the rafts to provide refuge for the tern chicks from the summer sun and predatory birds.
Launching the new Tern Rafts in 2007. © FoTR
Despite all this work over the years, Common Terns only seem to have bred at Wilstone when they were given a new raft! So, with another new raft, the terns bred once more. 2008 was the most successful year so far and the Common Terns raised about twelve chicks, of which seven were ringed.
And, without being given another new raft, our Common Terns bred successfully again in 2009, another record year.
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(Last Updated 05/2010)