Calidris alpina

Calidris alpina

The dunlin (Calidris alpina Linnaeus, 1758) is a bird belonging to the Scolopacidae family.

Systematics –
From a systematic point of view it belongs to:
Eukaryota Domain,
Kingdom Animalia,
Phylum Chordata,
Subphylum Vertebrata,
Aves class,
Order Charadriiformes,
Suborder Scolopaci,
Scolopacidae family,
Genus Calidris,
C. alpina species.
The terms are synonymous:
– Calidris variabilis Meyer & Wolf;
– Erolia alpina (Linnaeus, 1758);
– Pelidna alpina (Linnaeus, 1758);
– Tringa alpina Linnaeus, 1758;
– Tringa variabilis.
Within this species, the following subspecies are recognized:
– Calidris alpina actites Nechaev & Tomkovich, 1988: nests in northern Sakhalin and overwinters in eastern Asia;
– Calidris alpina alpina (Linnaeus, 1758) – nests in northern Europe and northwestern Siberia up to the Yenisei river, wintering in western Europe, on the coasts of the Mediterranean, in Africa and in southwestern Africa up to India;
– Calidris alpina arctica (Schioler, 1922): nests in north-eastern Greenland and winters in north-western Africa;
– Calidris alpina arcticola (Todd, 1953): nests in northern and northwestern Alaska and in northwestern Canada and winters in China, Korea and Japan;
– Calidris alpina centralis (Buturlin, 1932);
– Calidris alpina hudsonia (Todd, 1953): nests in central and northern Canada (Hudson Bay and winters in the southeastern United States;
– Calidris alpina kistchinski Tomkovich, 1986: Nests north of the Sea of ​​Okhotsk and south of Koriakia, north of the Kuril Islands and the Kamtchatka peninsula and overwinters in East Asia;
– Calidris alpina pacifica (Coues, 1861): nests in western and southern Canada and overwinters in the western United States and in Mexico;
– Calidris alpina sakhalina (Vieillot, 1816) – It nests in extreme north-east Asia and overwinters in eastern China, Korea, Japan and Taiwan;
– Calidris alpina schinzii (Brehm, CL & Schilling, 1822) – nests in south-eastern Greenland, Iceland, the British Isles, southern Scandinavia and the Baltic Sea and overwinters in southwestern Europe and northwestern Africa.

Geographic Distribution and Habitat –
Calidris alpina is a bird that occupies a vast range; it is present throughout Europe, in almost all of Asia (missing only in Myanmar, Cambodia and Bhutan) and Africa (missing in Angola, Zambia, Zimbabwe, Tanzania and Central African Republic); in North America it is present as far as Guatemala, further south and in the Caribbean it is in transit, as well as in Australia, New Zealand, the northern part of South America and the southern part of Africa. It is also observed on some islands of Oceania, such as Hawaii, Micronesia, Palau and Northern Marianas.
Its habitat is that of the coastal muddy beaches that it prefers as it finds the ideal conditions for feeding.
Habitat fragmentation has reduced the availability of suitable areas for these birds by reducing their size and increasing isolation. This reduced connectivity between habitats has reduced the movements of this species, making it more susceptible to inbreeding in these areas.

Description –
The Calidris alpina has a length of 16-20 cm, with a wingspan of 35 – 40 cm, for a weight that varies between 40 and 50 grams and has no sexual dimorphism.
It is recognized by the slightly curved beak downwards.
In nuptial livery it has a dark brown back, mottled with black brown and a showy black ventral spot. The winter plumage is dark gray.
The legs and the beak are black.
In the juveniles numerous longitudinal whitish streaks are evident on the rust-colored back.
The song is a faint and frequent “trui” which in the nuptial song turns into a series of buzzing “tru tru tru”.

Biology –
The Calidris alpina is a bird that nests in the coastal tundra: during the pass it is common along the coasts or in the ponds, sometimes gathered in numerous groups.
The nesting period is between April and June with only one brood per year. The nest is built in a small depression in the grassy ground and is sparsely covered with straw.
In it, 4 brown-olive-colored eggs are hatched, with large dark spots, which are incubated by both parents for 17-20 days.
The chicks are precocious, however they are hatched during early development. They begin to fly at around three weeks of age. Most of the brood care is provided by the male, as the female abandons the brood and often leaves the breeding area.

Ecological Role –
The Calidris alpina is a partial migratory bird that moves in the periods of April-May and July-November.
It is a very gregarious bird in winter, sometimes forming large flocks on coastal mudflats or sandy beaches. Large numbers can often be seen whirling in synchronized flight during migration stopovers or in their winter habitat.
This bird feeds on small invertebrates and seeds that it finds along the coastal muddy beaches, methodically collecting small foods. Insects constitute the main part of the diet in the nesting places; it feeds on molluscs, worms and crustaceans in coastal areas.
This bird currently has an extremely large range and although the population appears to be decreasing, the population is still very large. The International Union for Conservation of Nature (IUCN) has judged the threat to the species to be of “minimal concern”.
In addition, the Agreement on the Conservation of Afro-Eurasian Migratory Waterfowl (AEWA) applies to this species.
However, future management for the conservation of this species will have to focus on increasing connectivity between the various habitats.

Guido Bissanti

Sources
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– C. Battisti, D. Taffon, F. Giucca, 2008. Atlas of nesting birds, Gangemi Editore, Rome.
– L. Svensson, K. Mullarney, D. Zetterstrom, 1999. Guide to the birds of Europe, North Africa and the Near East, Harper Collins Publisher, UK.
Photo source:
– https://inaturalist-open-data.s3.amazonaws.com/photos/175947491/original.jpg