SCANS 3 - the birds

The area that we surveyed during SCANS 3 was made up of habitats that are very difficult to access in the UK. Our survey effort was centered on the shelf break, or over deep 'off-shelf' waters (3000 m at some points), with out transects taking us over the occasional seamount or bank. As such the suite of species we recorded was very different to what you might expect to see from land, or even on a more inshore survey. Some species such as northern gannet and fulmar are encountered throughout the marine environment, and we saw our fair share of those, but otherwise, we mainly encountered pelagic specialist species.

An obvious difference from surveying in inshore waters was the lack of gulls and auks. These groups make up a large proportion of the birds seen on inshore surveys, but out beyond the shelf edge they were few and far between. Puffins (usually immature birds) were seen occasionally, as were guillemots, but the only gulls we saw were the occasional kittiwake and the even more occasional lesser black-backed gull. Instead of these, the birds we encountered most frequently were various species of 'tubenose' - birds adapted for a life at sea, with a keen sense of smell to help them locate food. We saw plenty of Manx shearwaters, probably birds on foraging trips from one of their breeding colonies. We also encountered several sooty shearwaters, which were on a much longer journey, partaking in their annual loop of the north Atlantic having bred in the southern hemisphere.

Manx shearwater

Sooty shearwater

We also recorded European and Leach's storm petrels regularly. These tiny seabirds live and feed offshore for most of their lives, and during the breeding season, only return to their colonies at night, to avoid predators. Unfortunately their small size makes them difficult to photograph so you'll have to make do with this rather poor effort!

Leach's petrel

One species it was much easier to photograph was the long-tailed skua, as several of them came in to the boat to have a look. We encountered 53 of these birds in total - many more than we were expecting - the vast majority of which were immature birds. Little is known of the at-sea distribution of immature birds during the breeding season, and encountering this many in UK waters in the summer is certainly unprecedented. There is so much to still learn about seabirds and their distributions, populations and habits at sea, and hopefully, continued monitoring of seabirds at sea can help us discover more and more about them.

Long-tailed skuas

SCANS 3 - searching for seabirds in little known waters

While Mark T stood on the bow, making up part of the cetacean survey team, myself and Paul French enjoyed much more comfort, in an observation box in a lofty position (8.5 m) on the monkey island, from where we carried out our seabird observations. This is our view of Mark T (on the left) as he and Darren carried out their primary observer duties.

Primary observers at work

We were collecting data using the ESAS method, to a standard that will be compatible with the ESAS database. This means that the data will contribute to a database that contains over 3 million records of seabirds, with the first data collected as long ago as 1979. In spite of the fact that a lot of seabird surveys now use digital aerial methods, the ESAS database remains a hugely valuable resource on the distribution and relative densities of seabirds at sea in north west European waters. Adding the data collected on this survey is particularly important as data are relatively sparse over much of the area that we covered on SCANS 3. The figure below shows the locations of all of the ESAS data points (each tiny grey dot), and how sparsely they are distributed in our more western waters. The black line represents the coverage achieved during the first part of SCANS 3.

The distribution of ESAS data within (and beyond) the UK EEZ, before the SCANS 3 data were entered.

As the area was so data poor, Paul and I were hoping for a few surprises. Although the hoped for rarity didn't materialize, we saw plenty of interesting birds. See the next post in the for a summary of some of the great pelagic birds that we encountered!

SCANS 3 - Setting the scene

Mark Tasker and Mark Lewis have traveled far beyond the shelf edge north and west of Scotland, to take part in SCANS 3. This is the third in a series of Europe-wide, large-scale ship and aerial surveys to study the distribution and abundance of cetaceans in European Atlantic waters. Mark T is part of the dedicated cetacean observation team, with Mark L, along with Paul French (who very kindly volunteered his time, as well as a substantial proportion of his stash of Werther's Originals) making the most of an opportunity to collect bird data in what is a relatively data poor part of UK waters. The cetacean data will improve our understanding of these animal's occurrence throughout the survey area, as well as giving insight into any population changes, when used alongside data collected from previous surveys in 1994 and 2005. The seabird data will be added to the ESAS (European Seabirds at Sea) database, which has long been used to inform marine management, has been used extensively in the process of delivering marine SPAs (special protection areas), and is a valuable resource that can be made available for academic or other management purposes.

The first part of the survey saw us heading north and west of the Outer Hebrides, where we steamed transects through the areas coloured beige, and numbered 7 and 8 on the map below. This was a long journey from Aberdeen, but time was well spent, calibrating our very technical survey kit, gathering data along the way, and taking the opportunity to spot some of the most remote parts of the UK, such as North Rona, and Sules Skerry and Stack.

Map of the SCANS 3 survey blocks

Sule Skerry - part of the Sule Skerry and Sule Stack SPA

After completing these areas, Mark T has headed down to survey beige area 9 (I'm sure it's a lot more interesting than that makes it sound!) with the rest of the cetacean team. Mark L and Paul made use of a port call in Cork to return to land and head back to civilization having completed as much data collection as they could within UK waters. I'll soon be posting a few more details on the work that we were doing, and some of the incredible things that we saw.

Watch this space!