Wednesday, May 14, 2008

Arctic Seawatches - Spring movements of White-billed Divers

As I mentioned in a previous post, Niklas Holmström of Torshälla, Sweden has created an excellent website describing the excellent spring seawatching possibilities from Slettnes in Northern Norway (71.0605°, 28.2447°). As it happens, he and group of intrepid seawatching enthusiasts are there at the moment, braving the cold of the arctic spring and filing timely reports (with photos) on Niklas' site. Take a look!

One of the most striking results is the number of White-billed Divers (aka Yellow-billed Loons) Gavia adamsii they are logging. For example, 73 on 9th May 2008 and 69 the following day. I appreciate the impressive movement of White-billed Divers along the Norwegian coast is not a new phenomenon (e.g. from Skogsøy near Bergen [60.552°, 4.79608°]) but it got me thinking if there was anywhere else where one can see this is striking diver in such numbers?

Migrants are seen in small numbers from spring (May/June) seawatches in Alaska such as near Gambell on St. Lawrence Island (63.7809°, -171.742°) and from Point Barrow (71.3881°, -156.48°) but to my knowledge, never in the same numbers. I imagine there might be hot spots in the Eastern Palearctic but can imagine there are few observers able to reach these more inaccessible regions.

Another pressing question is where the Norwegian birds that are seen from Skogsøy and Slettnes are wintering? Are they simply widely scattered around the coastlines of Scandinavia , Scotland and into the Baltic or do they concentrate in offshore areas? For more on the spring passage of divers off Norway see Folvik and Mjøs 1995 and Julian Bell's Natural Born Birder website.

Of course, divers are not the only birds of special note at Slettnes and heavy passages of Pomarine and Long-tailed Skuas (jaegers) and alcids are expected with a supporting cast of Gyrfalcon and three species of eider (Common, King and Steller's). Persistence might be rewarded with something really cool such as a Ross's or Ivory Gull.

Folvik, A., Mjøs, A.T. 1995. Spring migration of White-billed Divers past southwestern Norway. British Birds 88: 125-129

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