Data reveals feeding habits

The UK is an internationally important breeding site for a range of species, including puffins   The feeding patterns of seabirds around the UK coastline can be can used to help identify the location of possible marine protection areas, a study says. Researchers compiled data on 25 species ' foraging behaviour, adding that feeding sites played a vital role in the success of breeding colonies.
There is just one Marine Conservation Zone in English waters but a network is expected to be decided by 2013.
"There is an increasing need to protect areas of sea for marine species because the environment is facing pressures - such as oil, shipping, gas and renewable energy," explained co-author Chris Thaxter, research ecologist for the British Trust for Ornithology (BTO).
"It is important not to let these events impact on the species that are using these areas."
He told BBC News that there was a discrepancy between the level of protection offered to the birds while they were on colonies and when they were searching for food.
"Seabirds are an important part of the marine ecosystems," Dr Thaxter said.
"Seabird colonies are relatively well protected but offshore areas are not - and that has been a big gap in [scientific] knowledge.
"This is the challenge that the government faces: deciding what areas to protect when they do not have the best evidence to hand."
Pinpointing sites
The team, which also included researchers from Birdlife International and the RSPB, said the protection of foraging areas was widely recognised as a key component to breeding successes.
"Direct tracking of individual seabirds, at-sea surveys of seabird distributions and data from other environmental variables... can be modelled to suggest likely areas of usage associated with particular colonies," they wrote.
The researchers listed data sets in a quality-based hierarchical order:
-    Direct studies - detailed data on locations, journey distance etc, gathered via technology such as radio-tracking and GPS devices (made up 21% of reviewed data),
-    Indirect studies - data that does not directly measure foraging ranges, but is information that allows estimates of species' foraging patterns (12%),
-    Survey method studies - when carried out during the breeding season, surveys can offer an insight into birds' foraging ranges (46%),
-    Speculative studies - considered to be the least robust of the four groups, these encompass a range of methods such as ring recoveries and author speculation (21%).
The study reviewed data for 25 seabird species, from 304 studies. The authors found that Manx shearwaters, northern gannet and northern fulmar had the longest maximum foraging ranges, covering 330-590km (200-670 miles).
The species with the shortest ranges were the red-throated diver and little tern, which cover just 9-11km.
The team added that by using the hierarchical approach, they had most confidence in the data on the northern gannet (mean foraging range: 230km), black-legged kittiwake (60km) and common guillemot (84km).
They had least confidence in the estimated ranges for the common gull (50km), common eider (80km) and Leach's/European storm-petrel (90km).
Dr Thaxter said the findings could be useful for policymakers: "The generic foraging range information could be a very useful tool, as a first step, to narrow the range of areas at sea that could be used by species that breed in the UK.
"This could then lead to informed decisions on where is best to locate the protected areas."
In 2009, the Marine and Coastal Access Act paved the way for Marine Conservation Zones (MCZs) to be established in English and Welsh waters. There are four regional consultation groups that are tasked with assessing what marine areas should be designated MCZs.
Scotland has its own legislation, but the Marine Act 2010 also includes powers for ecologically important areas of sea to be designated MCZs.
Dr Thaxter added that the review's methodology could also be used to review data from other nations.
"We actually reviewed studies outside the UK - this approach can be applied elsewhere," he said. "Overall, this would lead to the wider protection of seabirds."