Sterna hirundo - The Common Tern

 The Common Tern

By Lachlan Royle 

UK Population 

The UK population of Common Tern are summer visitors from the west of Africa and the coasts of Spain. In recent years their breeding range has expanded with warming climatic conditions, there are currently estimated to be 11,000 pairs within the UK that come to breed often in large colonies. In recent years there has been an 11.2% increase in its range expansion on British ground. They look very similar to the arctic tern but can be identified by smaller tail feathers and a small black marking on the tip of their beak. In the last 30 years alone their has been a 50% increase in the UK based population.

An individual on Earlham marsh

Behaviour 

Common terns are a relatively small species of tern with a wingspan between 75 and 100cm varying on the individual. They often nest inland in large colonies at wetland sites and are very territorial in the defence of their nests, they are also very identifiable by their loud noises they make both individually and then in colonies. They are very adept hunters and dive after fish just under the surface of the water, often with high success levels. They have a very strong sense of direction and can find their nests from previous years even if they have been buried or obscured. Historically like many other species of bird it was hunted for its feathers in the 19th century which were used to adorn clothing items such as hats. UEA has had a pair of common terns that have visited the island nest in the broad for a few years now however this year it was blown off anchor and ended up on the side of the lake. As a result the usual pair have now relocated perhaps permanently onto Earlham marsh just beyond the campus grounds, hopefully they will be able to successfully raise chicks once more.