Each year it is the fate of a small number of birds from Canada and the United States to be blown out to sea by an Atlantic storm. Some, diverted from their normal migration and assisted by powerful westerly winds, arrive on the coasts of Britain and Ireland.
Many birds are blown off course to Britain yearly, causing birdwatchers to get their binoculars out. Most species are seabirds, ducks, and gulls blown to British shores. Smaller species, such as the Common Rosefinch, Red-breasted goose, Desert finch, and Yellow-browed warbler, have all been seen in Britain.
Much of the excitement of seeing birds in the wild in Britain can be enjoyed by everyone. But there are occasions when even a nondescript bird proves to be a rich and rewarding discovery for the birdwatcher who can identify it as a vagrant that has come across the Atlantic from North America.
There are now thousands of records of birds of many species that have made this unintentional journey, ranging from large, powerful seabirds and ducks through many species of waders to the tiny warblers, vireos, and sparrows.
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What Are Vagrant Birds?
Vagrants are birds that have been diverted, usually by the weather, from their normal travels and arrive unexpectedly in a foreign country, perhaps thousands of miles outside their normal range.
Weather fronts can blow birds off course, although we only normally see one bird arriving at a time to our shores.
Typically, only small numbers of birds are involved in this movement, and they are often lone individuals, having lost contact with the rest of their species forever. The vagrants are often noticed by birdwatchers when they reach land, and then little is known of their fate.
It is thought that some start to fly back to America, but with generally prevailing westerly winds across the Atlantic, the attempt is not an easy one and can often be futile.
Some have been noticed joining a British flock of a related species, such as the Hudsonian godwit seen among a local flock of godwits. One rare occurrence was the reporting of a pair of spotted sandpipers from North America that actually bred in their new home in Skye. Unfortunately, the family did not survive. For American birds, the status of vagrant is likely to be the end of them.
How Many Vagrant Birds Reach British Shores?
It is known that every year well over 100 vagrants arrive from across the Atlantic and are recorded, although many more arrive without being seen.
Many species come to Britain as vagrants, with about 30 species being blow off course every year. Most are waders. Most of the rest are ducks and gulls. Grebes, terns, cuckoos, thrushes, vireos and others can also be seen on our shores.
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Birds On The Wing
More and more American birds are reported these days but this is possibly due tot he amount of birdwatchers and the ease of reporting them now. Fewer American birds were reported in the past, and identification guides were not as easy to come by.
When American vagrants were noticed, it was suspected that they had crossed the Atlantic by hitching a lift on a ship rather than having made the journey on their own.
A more accurate understanding of migrating birds has come from detailed research in more recent times. One species studied, the blackpoll warbler is a tiny bird breeding around Hudson Bay in Canada and migrating first to Massachusetts and the northern coast of New England.
From there, it makes its autumn flight to the southeast—out to sea. As it moves southwards, it reaches the southwest trade winds and is carried westwards to make landfall in the West Indies or South America. This journey can take four days of continuous flying after it sets out. The blackpoll warbler is able to fly for so long because it stores energy, in the form of subcutaneous fat, for the journey.
The distances involved in this flight are comparable to those from America to Britain across the Atlantic. Sometimes, the eastward movement of the winds across the ocean can catch migrant birds and deposit them across the Atlantic in two days.
Seabirds are perfectly capable of landing to rest and feed on the sea, and feature prominently on the list of vagrant birds. Because many species are the same on the east coast of North America, there would certainly be no chance of distinguishing between a gannet from America and one from Scotland.
However, many species do have differences, and many of the gulls can be differentiated by a keen birdwatcher. American species found in Britain and Ireland include ring-billed gulls, Bonaparte’s gull, and Franklin’s gull.
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The most widely seen American birds are the waders. The most common species, the pectoral sandpiper, has been seen in most counties of Britain during the last 50 years. Records are much more common on the southwest coast of England and Ireland where they tend to land. Almost all are found between August and October.
Some waders are clearly recognizable as American relatives of European species, while others have no direct counterparts in Europe. Many of the best British field guides now illustrate a range of American waders that have regularly been recorded.
Hard To Recognize
The more unusual American vagrants seen in recent years include the belted kingfisher, a much larger bird than our kingfisher, the American kestrel, a rather small falcon, the nighthawk, one of the many American nightjar species, and even a sandhill crane, a huge species of soaring migrant that astonished birdwatchers.
Another category consists of small birds that migrate by flying at night. Many of these belong to families not occurring in Europe. All the North American warblers, for example, are from a separate family.
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