Seabird migration

Without being market on some maps it runs a busy traffic lane passing the Öland coast. Along this migrates annually over a million seabirds from their wintering areas, sometimes from as far away as the southern hemisphere, with their nesting areas in the northeast. In the midst of this traffic lane is Öland, highly strategic for birders.

During spring and autumn spotting scopes are crowding at the protruding headlands on Öland. Birders gather to enjoy the large quantities of seabirds that pass. Some people do it in the hope of finding some rare species. Others find the greatest thrill in the counting. The number of individuals per species is now recorded as carefully as it is now possible, and the data reported later in to the “Artportalen” (Species Portal in Sweden), or end up in their own observation manual. Which bird’s increases and which are decreasing?

Spotting Scopes – a must?

To count seabirds is not easy. While some flocks passing so close that it is difficult to find time to count, is the second so far out that both counting as species identification is hard or impossible without a spotting scope. Most birders tend to alternate between binoculars, spotting scopes and “the naked eye” while they scout the airspace above the sea.
With spotting scope the time the birds can be studied is longer, which is often necessary if you for example want to find something spectacular, like a King Eider among the Common Eider, or a Red-breasted Goose among the Barnacle Geese. One tip is that if viewed from the side, it is usually easiest to start scouting the flock from the end and then scan forward.


Praktejder Lars Lundmark Sjöfågelsträcket ÖlandKing Eider, © Lars Lundmark

Towards the northeast in the spring and southwest in the fall

In the spring, many of the passing seabirds are on the way to their breeding grounds in the northern part of the Baltic Sea or along the Arctic coasts on the distant Siberian tundra. In the fall, they are headed back toward wintering areas in the Western Europe’s coastal areas, or in some cases further down to Africa.

Kentsktärna-Lars Lundmark Sjöfågelsträcket ÖlandSandwich Tern, © Lars Lundmark

Öland is passed then twice a year along the major migratory highway, from northeast to southwest. Dabbling Ducks, Swans and some Geese usually follow faithfully the coastline and stretches close or relatively close to the coastline. The same applies to Common Goldeneyes, Mergus and Cormorants. Even Terns and Gulls prefer to follow the coastline. The exception is the Little Gull which usually passes at “half distance”. Out here, from about half to maybe two kilometers out, passes also most Grebes, Tufted ducks, Greater Scaups and Skuas, but also a lot of Loons, Auks and Pochards like Eider, Long-tailed Duck, Common Scoter, Velvet Scoter and Red-breasted Merganser.

The right wind.

How close to the sea birds pass depends very much on the prevailing wind direction and strength. In onshore wind passing birds are usually closer to shore and are then easier to see. At the headwinds they often fly at low altitude and the visibility can then easily be obscured by waves and the swells.

In the spring the seabird migration, with the spectacular Eider migration in the Kalmar strait as its hallmark, is best with the wind from the southwest. The birds then pass near the west coast of Öland at a comfortable distance. In fierce tailwind the flocks can sometimes go cross the island instead. Clean headwind and bad weather leads instead to that the migration almost completely absents.


Ejder-Lars Lundmark Sjöfågelsträcket ÖlandCommon Eider, © Lars Lundmark

Dvärgmås Lars Lundmark Sjöfågelsträcket ÖlandLittle Gull, © Lars Lundmark

In autumn it is Öland’s eastern side, and winds from the southeast sector that is best for the rarer birds like the Greater Scaup, Little Gulls and Skuas. Also on the west side, in particular at “Stora Rör”, can the migration be good in the south-east winds, especially when the wind has been easterly also in the waters north of Öland. When the wind has been on a day or two, the migration usually slows up. This is usually referred to as”old wind” and is rarely beneficial if you are hoping for high yield numbers.

The right day

To predict, with certainty, a good migration day on the basis of only the weather forecasts is rarely done. Weather changes often have a positive effect on the migration intensity. In the fall it is common that the low pressures from the Atlantic comes in with a path of the center a good distance north of Öland with dominant winds from the southwest sector as a result. When such a weather situation is broken, and followed by a cold air intrusion by north and northeast winds, that often trigger a wave of migrating seabirds. The migration passes in these winds quickly and often at high altitudes. To seek out projecting headlands at the Kalmar strait, west coast of Öland, in this situation can pay off.

Typically, is the seabird migration most intense from dawn until noon. For some long migratory species like the Barnacle Goose and Brent Goose migration can under good conditions keep on all day. In the afternoons and evenings can sometimes be migration continued strongly, but is never as rich in species as in the morning.

Gråhakedopping-Lars Lundmark Sjöfågelstrecket ÖlandRed-necked Grebe, © Lars Lundmark

Vitkindad gås-Lars Lundmark Sjöfågelsträcket ÖlandBarnacle Goose, © Lars Lundmark

Prutgås-Lars Lundmark Sjöfågelsträcket ÖlandBrent Goose, © Lars Lundmark

The right place

In the spring, it is only a few seabird flocks that follow the east coast to the north. However, in the Kalmar strait and at northern Öland the migration can be all the more intense. “Stora Rör” is, thanks to that the Kalmar strait is the narrowest here, the best observation place, but with winds from the southwest the flocks will pass of great distances along the entire route from “Eckelsudde” up to the northern tip of Öland.Some other strategic locations are “Mörbylånga” and “Färjestadens” harbours, “Beijershamn” and “Ekerum”. From “Borgholm” and to the north occurs some adding to the flocks from the west, making places like “Horns udde”, “Byxelkrok” and the northern tip of Öland offering a particularly interesting seabird migration.

In the spring the flocks of migrating seabirds tends to be fairly species specific. Sure it happens that for example Common Scoters, Velvet Scoters and Long-tailed Ducks blend into the spring flocks of Common Eiders, but in the fall it is far more common for seabirds to form mixed flocks. These include flocks may also include birds from different species groups. Pochards can for example be mixed up with the Grebes, Loons and Auks.

The spring schedule

March is the month when the seabird migration usually starts, but first in the second half of the month, the curtain rises on this spring’s major feature – the Eider migration. Although Eiders declined sharply in number in the 21th century, is this migration, which mainly goes through the Kalmar strait, still a spectacular show. Most birds tend to pass around the end of March and April.

Storlom-Lars Lundmark Sjöfågelsträcket ÖlandBlack-throated Diver, © Lars Lundmark

Silvertärna-Lars Lundmark Sjöfågelsträcket ÖlandArctic Tern, © Lars Lundmark

April means that a limited migration of Red-throated and Black-Throated Divers gets started, with the Red-throated Diver as the earliest of the species. Barnacle Goose can during this month show a more spectacular migration, where over 10 000 individuals may pass within a few hours, a good migration day. The first Terns also passes during the month and the Sandwich Tern is first out. Some larger amounts of Auks is rarely seen in the spring, but single individuals and small flocks of mainly Razorbills and Black Guillemots passes during April and May, as well as some Common Murres. A great number of species of Geese, Ducks and Gulls passes, but rarely in large numbers.

May is usually the month when species such as Black-Throated Diver, Red-necked Grebe, Arctic Tern and Common Tern has its stretch tops. Also for Common Scoter and somewhat Long-tailed Duck is the month an intensive migration period. Towards the end of May and quiet suddenly Brent Goose passes by, often very concentrated in time. At the top, five-digit number in a single day is not uncommon.

Sjöorre-Lars Lundmark Sjöfågelsträcket ÖlandCommon Scoter, © Lars Lundmark

Gravand-ottenby Lars Lundmark Sjöfågelsträcket ÖlandCommon Shelduck, © Lars Lundmark

Around midsummer a migration of Eider males are crossing towards the south, mainly in the Kalmar strait, but also along the east coast some flocks are seen. Most are heading for the mussel banks outside of the coast of the Danish islands for their summer moult, when for a time they become completely flightless. Even some Common Shelducks have begun to migrate towards the south.

The autumn migration

If autumn Öland’s coastline works as a hinge line and captures flocks along the east side. Most of the birds will be coming from the easy or the northeast. When they get Öland within sight they fold and follow the eastern coast to the south. The further south on the island, the more and larger the flocks will be is the rule of thumb.

The autumn migration can be monitored from almost anywhere along the eastern side of the island, but protruding capes are generally best. Among the safe and proven sites include “Kapelludden, Bläsinge hamn, Gårdby hamn, Stenåsa badet, Seby läge and Näsby badet”. South of “Näsby badet” the coastline folds of to the southwest, which means that the migrating seabirds that continues in the south-south-westerly direction crossing too far from the southern tip of Öland to be enjoyed properly.

Skedand-seby-Lars Lundmark Sjöfågelsträcket ÖlandNorthern Shoveller, © Lars Lundmark

Sångsvan-Lars Lundmark Sjöfågelsträcket ÖlandWhooper Swan, © Lars Lundmark

Sometimes it happens that some flocks go across the island to the west and southwest. This applies mainly to Swans and Geese, and especially when the weather is favorable, with good visibility and tailwind.

In the Kalmar strait the seabirds that have followed the mainland coast are crowded together as in a funnel with the spout at “Stora Rör” where the strait is as most narrow. “Stora Rör” therefore becomes the best place to observe the seabird migration at Oland’s western side, but also “Horns udde” and “Äleklinta” in the north and “Beijershamn” in the south can offer great views of the migrations.

The autumn’s schedule

July means sun and bath for us, but at the end of the month, the fall started for the Terns, who then begin its autumn migration. First is the Arctic Tern – perhaps not surprising since that species migrates further than any other, and will migrate as far as down to the Antarctic waters.

August then continues with that the Arctic Tern gradually is replaced by the Common Tern, often simultaneously with flocks of gulls beginning to migrate south. Now the autumn migration also begins for the Common Scoter and Dabbling Ducks.

Fisktärna-Lars Lundmark Sjöfågelsträcket ÖlandCommon Tern, © Lars Lundmark

Kricka-Lars Lundmark Sjöfågelsträcket ÖlandTeal, © Lars Lundmark

September is one of the year’s best months for seabird migration. Several Dabbling ducks, as Eurasian Widgeon, Northern Pintail, Teal and Northern Shoveller, all have their migration peak this month. Common Scoter and Brent Goose, however, the two ducks that dominates in terms of number. Common Scoter has a much extended migration period from July to early December, while the Barnacle Goose has a more concentrated migration, and may in the end of September pass in the tens of thousands.

October is the years prime seabird migration month. It has the highest number of seabirds passing along the coasts this time of year. Eider dominate, followed closely by Barnacle Goose that particularly in the second half of the month can really dominate the skies, both along the coast and inland. Now also the migration of Gulls like Common Gull and European Herring Gull reaches its peak. South migrating Red-throated and Black-throated Divers are a common sight, and in the middle of the month flocks of Tundra Swans are seen.

Fiskmås-Lars Lundmark Sjöfågelsträcket ÖlandCommon Gull, © Lars Lundmark

Salskrake-Lars Lundmark Sjöfågelsträcket ÖlandSmew, © Lars Lundmark

November means that seabird migration gradually subsides, but some species such as Whooper Swan, Red-throated Diver, Mallard, Tufted Duck, Common Goldeneye and Black Guillemot has now their migration peak. The single most common species migrating in November is the Long-tailed Duck.

Gulls like European Herring Gull, Great Black-backed Gull and Common Gull continues to migrate to the south and they are sometimes joined by Little Gulls. From their breeding grounds in the northern Scandinavia and Russia, they are now migrating towards the Atlantic. Outside the breeding season, they are completely pelagic, ie they live their lives far out on the open sea. During late autumn when there is southeast fresh breeze to strong gale, they can be pressed towards Öland’s east coast in surprisingly large numbers.

When the winter darkness settled over Öland and the cold comes in December the seabird migration is generally over, but with mild autumns can decent migration occur even well into the month. If the Baltic Sea freezes can flocks of Goosander, Red-breasted Merganser and Smew turn south even during the years last weeks.

Ölands-fåglar-ÖOF Öland

Source: Ölands Fåglar © Ölands Ornitologiska Förening ÖOF  (authors this chapter: Bertil Breife)


Pictures: see each picture

The book: Ölands Fåglar, 496 pages (only in Swedish), can be ordered at Naturbokhandeln
ISBN: 9789188124555