Novel methods identify important marine areas for the
five tern species breeding in the UK
With 119 bird species making significant use
of the marine environment around the UK, JNCC’s Seabirds and
team are working to compile a coherent network of marine protected
areas to support future generations of these birds. Such protection
areas are only a small part of the efforts required to halt the
unprecedented rate of biodiversity loss being experienced.
The five species of tern breeding in the UK - Arctic tern,
common tern, Sandwich tern, roseate tern and little tern
- are long-distance migrants, wintering along the
coasts of west Africa, or in the case of Arctic tern, the oceans of
Antarctica. The latter two species are among the rarest seabirds
breeding in Great Britain. All five terns are listed on Annex I of
the EU Birds Directive and therefore the UK is
required to classify Special
Protection Areas (SPAs) for them.
Currently there are 57 SPAs for which at least one species
of tern, as a breeding colony, is a qualifying feature.
There are, however, currently no SPAs in the marine environment for
During the breeding season terns forage at sea within a
restricted range around the colony as they return frequently to
feed and brood their chicks. Food availability within the foraging
range of breeding colonies is crucial to breeding success, so since
2007 JNCC has been working with the Countryside Council for Wales
Resources Wales), Natural England, the
Northern Ireland Environment
Agency and Scottish Natural Heritage to identify
important foraging areas at sea used by terns for
consideration as marine SPAs.
In order to identify these foraging areas for the four larger
species of tern, a novel visual tracking method has been used to
collect data at selected colonies around the UK. Individual terns
were followed in a rigid inflatable boat as they went on foraging
flights during the breeding season. A cutting edge habitat
modelling approach developed in collaboration with statisticians
then allowed the surveillance team to make predictions of foraging
distributions around unsampled colonies.
A simpler approach to defining a generic
foraging extent has been applied to little terns as these forage
very close to shore and to their breeding colony.
A workshop with the country nature
conservation bodies at the start of the year, followed by a
quantitative model assessment, has led to a strong degree of
confidence in the models and a positive outlook for the tern
project as a whole, with minor model refinements and boundary
The aim is to finalise a suite of suitable
marine areas for consideration as possible marine SPAs by December
2013 and to publish a report on the work on the JNCC website early