Wednesday 3 April 2013

Seabird die-off on the east coast of Scotland

March 21, 2013: A few hours in Edinburgh
March 22, 2013: Oban, Scotland
March 26, 2013: Rare duck in Scotland!
March 26, 2013: Aberlady Bay, Scotland
March 30, 2013: Unique photo of a lifer (Paris, France)
March 31, 2013: Photos d'oiseaux de France (Paris, France)
April 2, 2013: Seabird die-off on the east coast of Scotland

About a week ago, the local Scottish listserv started buzzing with reports of people finding dead seabirds, predominately Atlantic Puffins, along the coast near the mouth of the Firth of Forth. With Laura and I having returned from France, we decided to spend the day along the north coast of the Firth, in the town of Kirkcaldy. It was actually a beautiful day for a change and we managed to see close to 50 species of birds as well as explore a castle. However the low-light of the day was when we discovered that the seabird die-off was not just limited to the south coast of the Firth.

dead Razorbill - Kirkcaldy, Scotland

The above Razorbill was one of the first dead seabirds we came across. While it looked relatively fresh, most of the carcasses were probably a week old or more. In one particular area, the tidal wrack was concentrated in one area due to the geography of the land. Here, about 30 dead seabirds were found.

dead alcids - Kirkcaldy, Scotland

In the above photo, it appears to be mostly Common Murres with a single Razorbill and a single Atlantic Puffin.

Atlantic Puffins certainly seemed to be hit the hardest as they were by far the most numerous species. As depressing as it was to come across such a sight, it also provided a rare opportunity to see some of these species up close. I was surprised at how tiny the puffins were compared to the murres.

dead Atlantic Puffin - Kirkcaldy, Scotland

I had never seen a Razorbill, Atlantic Puffin, or Dovekie in the U.K. before. It was super depressing that the first ones I laid eyes on were dead along the beach. Here is only the second Dovekie I have ever seen.

dead Dovekie - Kirkcaldy, Scotland

The carnage wasn't limited to just alcids. We also came across 5 European Shags, 2 Northern Gannets, 1 Black-legged Kittiwake, 1 Common Gull, and several unidentified birds. Reports in other regions included Common Seal, Harbour Porpoise, and many Black-legged Kittiwakes. Evidently this was a massive die-off that was widespread across many taxa.

dead Gannet and Puffin - Kirkcaldy, Scotland

Two of the birds were banded - both European Shags. If anyone knows who I can send the band combinations to, please let me know.

European Shag  band

The total number of dead seabirds we found in about 4 km of coastline included:

53  Atlantic Puffin
24  Common Murre
14  Razorbill
1    Dovekie
8    alcid sp.
5    European Shag
2    Northern Gannet
1    Common Gull
1    Black-legged Kittiwake
3    gull sp.
1    bird sp.

113 total birds

What would cause a massive die-off of birds like this? It was not due to an oil spill, as all of the birds were clean, plus there have been no reports of large gulls (which are often the victims of oil spills). Disease seems unlikely too since again, there were no large gulls and the die off was widespread with many species. It appears that in this case, it had something to do with food shortage.

For about a week, the east coast of Scotland had been hit hard with strong easterlies. I don't know too much about the prey species of these seabirds, but perhaps the strong winds changed the dynamics of the fish populations which are crucial to the survival of these seabirds. The strong winds may have also pushed some of the birds closer in to shore, making it difficult for them to acquire sufficient prey in a weakened condition. If anyone has experience with these sorts of things I would love to hear an opinion on it, since I am just guessing.

dead Atlantic Puffin - Kirkcaldy, Scotland

Almost all of the birds we came across were adults. Surely this can be devastating to some seabird colonies in the immediate future. However, with most things (including this) there is a silver lining. These events are natural and happen on a regular, periodic basis. These birds have evolved in such a way that they can withstand occasional die-offs like this - and perhaps these are even beneficial to these populations in the long term due to this rapid natural selection event. Chances are that weaker birds are affected more than stronger birds, thus increasing the overall genetic "strength" of the population by eliminating birds with weaker genetics.

The problem is that with already declining seabird populations, it is much more difficult and it takes a longer period of time for populations to recover from episodes such as this.

I will finish this post with a photo of a live Razorbill we saw. Two immature Razorbills were sitting in the water very close to shore. Who knows if they were survive, but since the die off occurred about a week ago I would say that their chances are good.

Razorbill - Kirkcaldy, Scotland

Razorbills - Kirkcaldy, Scotland


Joe Sci said...

What about a possible die-off of a massive algal bloom, and subsequent ingestion of harmful algal toxins? Algal/cyanobacterial toxins are not species-specific.

Pat Work said...

Hi Josh,

You can use this website to send in your ring records and they should get back to you. There was a large number of shags found dead on teh Aberdeenshire coast earlier this year, many ringed as well.


Anonymous said...

Thanks for the website link! I'll send them in and see what they have to say.

Anonymous said...

Sounds interesting, Kellie. I will do some research into that...