Huge influx of Manx Shearwaters

October 28th 2010

Huge influx of Manx Shearwaters.

Sea watching for birds or cetaceans can often draw a blank.

Then occasionally it is spectacular and enormously rewarding as anyone lucky enough to have been looking out to sea over the few days around 14th September 2010 would agree. The sight of hundreds and hundreds of black and white birds effortlessly skimming over the waves off the shores of Assynt was one of those occasions.

Holiday time

We had arrived in Assynt on Saturday the 11th and, after unpacking the binoculars, usually done within the first two minutes, we spotted around a dozen Manx Shearwater or ‘Manxies’ out in Eddrachillis Bay. What a start we thought since two or three Manxies is usually a good record.

Sunday gave more sightings of tens of Shearwater at Culkein Stoer, Rubh’an Dunain and Stoer Head then around 200 at Balchladich. These birds together with a good number of Gannets, had us wondering what we had missed, or might yet see!

Monday, well it was pretty wet and windy so we caught up on our reading, went to the shop and decided tomorrow would be the day to visit the sites and see what the weather had brought in – memories of the Grey Phalarope from 2008 came flooding back.

Tuesday dawned dry-ish and very windy from the WNW so first stop Bay of Culkein at 10am. We hardly got the car stopped when hundreds of Shearwater and Gannets could be seen out towards Rubh’an Dunain. The sky was full of them, incredible.

Don’t forget the sandwiches!

On with the full wet weather gear, grab the binoculars and scope and out to the arch, we forgot the sandwiches!

The scene that built as we walked to the arch was amazing, birds everywhere, some diving, some wheeling, some gliding, some chasing, others sitting on the water. Shearwater, Gannets of all ages, Fulmar, Kittiwake, Great and Arctic Skua, Guillemot and Razorbill. We counted 700+ Manx Shearwater, one Sooty Shearwater and 300+ Gannets, the sky and sea from Point of Stoer to Eilean Chrona was full, what a sight. The Shearwater should have been on passage, but they weren’t passing, they were clearly feeding, but on what?

These birds were not miles out but all within 150-200 metres, some even closer – one Arctic Skua flew a few feet over our heads. It was really windy and the dark blue waves were smashing to white on the rocks at the arch so we could not hear the Gannets which are noisy when feeding like this. Shearwater are basically silent away from their nest sites so no need to listen for them.

A few sleet showers came and went which only added to the wonder and awe as the birds never stopped feeding or flying.

We watched this spectacular show for four hours but decided we needed to do a bit of feeding ourselves so headed back to the car. The next few hours also gave us three Brent Geese and our first two skeins of Pink-footed Geese of the ‘winter’!! The wind from the NW was bringing in many passage migrants with juvenile Knot, Turnstone, Black and Bar-tailed Godwit and Sanderling all appearing in Bay of Culkein over the same few days.

The Manx Shearwater

Back to the Manx Shearwater, and a wee bit of information about them.

They are in the same family of birds which includes the Fulmar hence the rapid and stiff winged flight. Their wings are perfectly adapted for life at sea being long and narrow allowing them to make use of the airflow over the sea, in fact Manxies rarely fly above 10 metres. Because of this style of flight the birds can remain airborne for long periods of time with the use of little energy reserves.

The UK breeding population of Manxies is around 290,000 pairs, and they spend the winter in the tropical seas off eastern South America. They, like Puffins, nest in burrows and are monogamists. Because they are not very agile on land, with their feet being set far back on the body, they are vulnerable to predation from gulls and only return to their burrows at night spending the day out at sea feeding. Their food, which consists mainly of small fish, crustaceans or surface offal, is seized from the surface or caught by plunging or diving to pursue it.

Manx Shearwater generally live for around 15 years but one bird which had been caught and ringed on Bardsey Island National Nature Reserve, off north-west Wales, when it was 4-5 years old, on 22nd May 1957 was re-caught on 4th April 2004 making it 51 years old. This same bird had also been re-caught on 8th July 1961 and 16th April 1977.

More to read

If you want to read more about Manx Shearwater then here is a link to their ‘Species Focus’ page on the British Trust for Ornithology (BTO) website. Or if you want a really weighty read then try ‘The Manx Shearwater’ by M Brook from 1990.

An Arctic Tern from the Farne Islands which made the news very recently was a relative youngster, compared to that Shearwater, being ’only’ 30 years, 2 months, and 23 days old – again determined because it had been caught and ringed, on the Farnes, as a chick on 28th June 1980.

Insider knowledge

Andy Summers, the Senior Highland Council Ranger for Sutherland, had been speaking to a local fisherman about the Shearwater, he gave Andy some key information. The Shearwater were feeding on small herring which, for some reason, had been pushed close inshore, he had never seen such a sight in all his 40 or more years. The herring shoals would explain the Gannets as well which nicely answers the “what were they feeding on” question.

What about ringing?

We always used to worry about the ringing of birds – when a metal numbered ring or a combination of coloured plastic rings are put on to, generally, the legs of birds for research purposes. It seemed the rings could be a bit of a hindrance to the wearer but the two records above help show that they do not have any detrimental effect on the birds. In fact if it were not for ringing projects much information about the lives of our birds, both resident and migrant, would still be unknown and suitable conservation measures would be more difficult to take to help protect them.

On that subject have a close look at any Twite you see around as there is a colour-ringing project taking place in Clachtoll. The Assynt birds have a combination of metal, green and white rings on their legs.

You may also be lucky enough to see some Twite with yellow or red colour rings – these are birds from different projects in other parts of Scotland, mainly Orkney and Grampian. We found one in Clachtoll on the 15th which had a metal ring over a red ring on its left leg – it had been ringed on West Mainland, Orkney last winter. How do we know this? Well, if you see a colour-ringed bird and carefully note the combination of rings on each leg then you can report it via the British Trust for Ornithology website – just click on the Report Something page on their website and put in your information. After a few days, or weeks, you should get a report back giving you the life history of the bird.

Needle in a haystack

Remember the mention earlier of the single Sooty Shearwater off Rubh’an Dunain? How can one bird show out of over seven hundred others all wheeling, turning, dipping, diving? The answer is it simply jumps out at you.

The Sooty is about one third bigger than the Manx and is chocolate-brown with just some greyish-white feathers on the underside of its wings. The Manxies are basically black above and white below which, no matter what the weather – sun or sleet, flashes their presence.

The exciting thing about that single Sooty was we were looking at a bird which breeds in the southern hemisphere but spends its ‘winter’, our summer, in the north Atlantic. So this bird was preparing to head south to start breeding whereas the Manxies were heading south after breeding. All this happening just a few hundred metres off the shores of Assynt.

Finally a message from Andy Summers on the 22nd confirmed the Shearwater had gone and things were back to ‘normal’.

Wonder what the next storm will bring – enjoy.

DnA Haines

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