Gyrfalcons are 'secret seabirds'

20 June 2011 Last updated at 02:07 By Matt Walker Editor, BBC Nature Ice lover and ocean wanderer The world's largest falcon, the fast, taloned gyrfalcon, is a secret seabird, scientists have discovered.

Gyrfalcons living in the high Arctic overwinter out at sea, spending long periods living and hunting on pack ice.

It is the first time any falcon species has been found regularly living at sea.

The birds likely rest on the ice and hunt other seabirds such as gulls and guillemots, over what appears to be one of the largest winter ranges yet documented for any raptor.

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Some gyrfalcons actually spend large amounts of time living and hunting over the ocean”

End Quote Ornithologist Kurt Burnham "I was very surprised by this finding," said ornithologist Kurt Burnham who made the discovery. "These birds are not moving between land masses, but actually using the ice floes or pack ice as winter habitat for extended periods of time."

"Previously, all species of falcon were considered to be land-based birds."

Dr Burnham of the High Arctic Institute, Illinois US and the University of Oxford, UK, together with colleague Professor Ian Newton of Centre for Ecology and Hydrology in Oxford, studied the seasonal movements of gyrfalcons (Falco rusticolus) by tagging 48 birds with radio transmitters.

This allowed them to track the movements of the birds living in three areas of Greenland: Thule in the northwest, Kangerlussuaq in the west, and Scoresbysund in the east.

They found a huge amount of variation between individual birds.

Juvenile male gyrfalcon in Thule area, northwest Greenland

Birds living on the west coast had winter home-range sizes of between 400-6,600km square kilometres.

Those on the east coast ranged far more widely, covering between 27,000-64,000 square kilometres. Some of these had no obvious winter home ranges and travelled continuously during the non-breeding period, spending up to 40 consecutive days at sea.

During the winter one juvenile female travelled more than 4,500km over 200 days, spending over half that time over the ocean between Greenland and Iceland.

"Others had observed gyrfalcons sitting on icebergs and over the ocean but it was always assumed they were only over the ocean for a short period to hunt and then flew back to land," explained Dr Burnham.

Continue reading the main story Falcons, hobbies and kestrels are all in the genus FalcoPeregrine falcons are one of, if not the, fastest animals in the world. They are believed to achieve speeds of over 200kph (124mph) when plunging from the sky in pursuit of preyEleonora's falcon switches its diet from insects to birds depending on the season"We show that some gyrfalcons actually spend large amounts of time living and hunting over the ocean and pack ice, and that sea ice is actually an important and previously unknown winter habitat for [them]."

Gyrfalcons in Iceland and the low Arctic are thought to be residents, staying in the same location all year. In the high Arctic, gyrfalcons are known to be migratory, but little was known about where they overwintered.

A few other falcons also cross the ocean when migrating, such as peregrine falcons crossing the Gulf of Mexico. But the gyrfalcons are doing more than just moving between land masses in this way.

"These individuals are likely resting on icebergs and ice floes and hunting the seabirds, such as black guillemots, dovekies, and species of gull, that are using the same habitat," said Dr Burnham.

The size of the bird's home range over the ocean also surprised the scientists.

Adult male gyrfalcon tagged with satellite transmitter in Scoresbysund area, central-east Greenland

Dr Burnham told the BBC: "The other main finding is the huge area that some of these individuals are using.

"In the big picture this shows how adaptable and mobile gyrfalcons have to be in order to survive and reproduce in the harsh arctic environment they live in.

"Food or prey can be scarce during the winter, and having the ability to travel somewhat long distances on a daily basis and spend long periods of time away from land increases their chance of survival.

The research, he added, emphasises how specialised many Arctic species are, in order to survive in an extremely difficult and inhospitable environment.

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Longline fishing killing seabirds

8 June 2011 Last updated at 09:56 By Victoria Gill Science reporter, BBC Nature Albatrosses will dive to reach food just under the surface Up to 300,000 seabirds are killed every year by longline fisheries, according to a study.

This new global estimate of seabird bycatch was carried out by scientists from the RSPB and Birdlife International.

Commercial longlines can be hundreds of kilometres long, with more than 1,000 bait hooks along the line.

Continue reading the main story Albatrosses are extremely efficient flyers, using up more energy when landing and taking off than they do while in the airThe tubenoses is an order of seabirds which contains the albatrosses and various families of petrels. They get their name from their prominent nostrilsSeabirds, including endangered albatrosses, often dive for the bait and become ensnared by the hooks.

Dr Orea Anderson from the RSPB, who led the study, told BBC Nature that the study took four years to complete.

She and her colleagues compiled all the available data on seabird bycatch from fisheries throughout the world.

This pinpointed some fishing fleets that were particularly problematic.

One Spanish longline fleet on the Gran Sol grounds off the coast of Ireland, for example, could be responsible for killing about 50,000 birds annually, according to the review.

The Japanese tuna fleet was also highlighted; it is estimated to have claimed 20,000 birds each year and to have had the largest impact on albatrosses.

Longline fisheries claim an estimated 300,000 seabirds annually Simple solution

The numbers of seabird deaths are unsustainable at the moment," said Dr Anderson.

"All we need to do to reduce that mortality is use bird scarers where the lines enter the water," she said.

"Or weight lines so the bait hooks are beyond the reach of a seabird's dive."

The RSPB has called on regulators to make the use of these methods mandatory for longline fisheries.

Dr Cleo Small, senior policy officer for the Global Seabird Programme and co-author of the review, commented: "With the UK's Overseas Territories in the South Atlantic holding a third of the world's breeding albatrosses, the UK has a major responsibility to ensure seabird-friendly fisheries.

Albatrosses often dive for bait on the line and become ensnared on the hooks

"The findings of this review (also) place a heavy onus on the forthcoming EU Plan of Action for Seabirds to deliver a robust set of remedial measures capable of reducing the impact of longline and other fisheries on seabird populations in EU waters and beyond."

Dr Andy Clements, director of the British Trust for Ornithology commented: "The importance of the UK Overseas Territories, holding such a significant proportion of the world's breeding albatrosses, means we have a special responsibility to take notice of these scientific findings, and to seek funds for further research work to support global seabird conservation."

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