Dunlins are one of the most common species of wader and are often used as a reference when identifying the other Calidris- species. They are the size of a starling. Older birds in nesting plumage are unmistakeable with their distinctly marked black belly plumage. Males are smaller and have a smaller bill than females. The southerly subspecies schinzii differs from the nominate subspecies alpina in that the belly patch is not completely black, sometimes to the extent that there are only the odd black flecks on the belly. A direct comparison shows the southern variety to be smaller, slimmer, shorter billed and often less colourful. They are relatively easy to identify in their other plumages, but the young southern dunlin can be tricky. The combination of short (sometimes very straight) bill, diffuse yellow-brown face and faint flecks on the sides of the body mean that the juvenile Southern Dunlin can give a slightly strange impression.
Source: ArtDatabanken. (2019).
The southern dunlin (Calidris alpina schinzii) occurs in coastal meadows around the Baltic Sea, as well as in the British Isles and on Iceland. The Baltic population was estimated to be 500-640 pairs in 2011 and since then numbers have clearly reduced, perhaps as much as by half. In Sweden they are found only in southwestern Skåne and on Öland. In Skåne the numbers are now under 10 pairs (2022) and on Öland probably around 60-70 pairs. In parts of Skåne the southern dunlin was one of the most common nesting waders as recently as the beginning of the 1900s. In the middle of the 1980s they had reduced significantly in Skåne, but around Foteviken there were still over 100 pairs left. In Skåne the southern dunlin has reduced by at least 95% in only 50 years and probably by 99% in 100 years. On Öland the reduction is probably less but the numbers have at least halved in around 50 years.
The southern dunlin wants damp, grazed coastal meadows. The grass should ideally have tussocks and areas with slightly taller grass where the youngsters can hide. The nest is hidden on the ground, and they prefer to make their nest close to where lapwings nest, as the lapwings are good at driving away predators such as crows. They normally lay 4 eggs and both the male and the female take turns brooding for around 3 weeks. When the eggs hatch, the male and female stay with the chicks for the first week. The chicks have almost fully grown legs and bills when they hatch, and they begin to search for food themselves after only a few hours. In the beginning they eat mainly insects and certain small beetles. After the first week the female often leaves, and the male is left with sole responsibility for the chicks for 1-2 weeks. After about 2-3 weeks the chicks can take care of themselves and at this point they learn to fly. They can now be out in the open more and forage for food on beaches where the sea washes up small animals. They fatten themselves up for the long flight to Africa. If they survive the winter, they normally return to approximately the same area where they hatched in around April of the following spring.
Differences between the northern and the southern dunlin
- Somewhat shorter bill
- Slightly smaller and slimmer
- Somewhat more diffuse colours
When a species or a subspecies declines at such a fast rate as in the case of the southern dunlin, there is normally more than one reason for it.
In Sweden, and in other countries around the Baltic Sea, a comprehensive system of drainage (reclamation) of the landscape began in the second half of the 1800s and became more widespread in the beginning of the 1900s. This caused a major reduction in natural wetlands and wet coastal meadows and in certain parts of Sweden they disappeared completely. This obviously disadvantaged the wading birds who had evolved over thousands of years to make the best of these environments. It also meant that predators like foxes and badgers quickly appeared in the reclaimed areas. The reduction in the hunting of these predators over the past 100 years has also disadvantaged waders.
In the beginning and the middle of the 1900s, in many places hedgerows with bushes and trees were planted down towards the water meadows, where there had previously been open and wide-stretched areas. These have become the perfect place for predators such as foxes, badgers, and crows to get closer to the waders’ eggs. Checks on nests during the breeding season made in Halland, Skåne and southern Öland over the past 20 years have shown that predation of eggs in some places has been 70-100% per year and even in the best result, around 50%.
The factors that have made the southern dunlin critically endangered around the entire Baltic Sea area have also disadvantaged six other wader species that nest in a similar way and in approximately the same biotope: lapwings, oystercatchers, redshanks, ruffs, curlews and ringed plovers. By trying to save the southern dunlin, we also help other species to adapt themselves to coastal meadows.
Humans have shifted the balance of nature in many ways and this has severely disadvantaged these waders. We will now try to recreate natural wetlands and coastal meadows as well as bringing in measures to restrict predators in order to help the waders again.
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The last stand for the southern dunlin
With financial support from the Swedish Postcode Lottery
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