Common terns are elegant summer visitors to UK coasts and inland waters. Their welfare as colonial nesters depends on safe nesting islands and fish availability in surrounding waters.
Common tern welfare is inseparable from fish availability. Sand eel population crashes, driven partly by industrial-scale fishing and partly by ocean warming, have meant breeding failures on a massive scale - adults unable to provision chicks adequately, resulting in mass chick starvation. Colony welfare is also vulnerable to introduced predators; a single mink can kill dozens of nesting adults and chicks. Floating nesting rafts provide predator-free alternatives that dramatically improve breeding welfare where natural islands are absent.