The little ringed plover and common ringed plover

Autor: Magdalena Zadrąg    

Smaller cousins of gulls, the plovers can be found on the Vistula beaches. Among these difficult to spot birds that are running on the sand and gathering from the ground small insects and other invertebrates, in Poland it is easiest to find the little ringed plover (Charadrius dubius) and the common ringed plover (Charadrius hiaticula).
Both species are considered not to breed in large numbers, and the common ringed plover even in smaller numbers. The little ringed plover is practically in all our country’s lowlands, and breeds on sandy beaches, flood areas and sand dunes. There is little information about the numbers of the little ringed plover in Poland. The common ringed plover has considerably lower reach, limited mainly to the Vistula, several other large rivers and the Baltic coast. Their numbers are calculated at 330-400 pairs and decreasing, thus it was entered in the Polish Red Book of Animals as an endangered species. Poland is an important area during migration for both species.

Sieweczka rzeczna (fot. M.Szymański)

Sieweczka rzeczna (fot. M.Szymański)

Identification
Plovers are small birds, the little ringed plover reaches 15-18 cm in body length, and the common ringed plover 17-19.5 cm, hence both species are smaller than a starling. Both plovers have quite long legs, white underbelly, beige and brown top of the body. Both species also have a distinctive black marking on the head and a collar on the neck, but they differ in the detail. As the name in Polish indicates, the common ringed plover has a more distinct and thicker collar, and its bill at the base is orange, while the collar of the little ringed plover is thinner, the bill is all black, and apart from that its eye is surrounded by a so-called ocular ring with a distinct yellow colour. Plovers are smaller and more dumpy than most of the other members of the Charadriiformes group, that is the little stints and sandpipers.

Little ringed plover. Photo M. Łukawski

Little ringed plover. Photo M. Łukawski

Common ringed plover. Photo A.Tabor

Common ringed plover. Photo A.Tabor

Breeding
Plovers come to Poland in April or May. After arrival they join in pairs and occupy breeding territories. Common ringed plovers breed in valleys of big rivers, usually relatively close to the water. Little ringed plovers on the other hand are not so fussy when it comes to a nesting place. There are known cases of even nesting on roofs of supermarkets. Generally plovers require sandy or gravelly areas with little vegetation.
Plovers’ nests are small holes in the sand or gravel, sometimes paved with a small amount shells or small pebbles. The male digs several such holes, but eventually it is the female that chooses which will become the nest.
Plovers most often lay 4 yellow and brown, finely speckled eggs, which are camouflaged on the similarly coloured base. The male and female take turns to incubate the eggs and when they notice a predator hanging around in the area, they get up and quickly flee the nest, usually making noise to attract attention to themselves. The predator is then most often interested in the bird and moves away, when it is no longer a danger to the eggs, then the adult bird returns to incubate the eggs.
After about 3-4 weeks chicks are hatched from the eggs which are typical nestlings, as they remain in the nest only until they are completely dry, then they wonder together with their parents and from the first day learn about life and to look for food. Both parents lead the chicks, which are able to fly after about 4 weeks.
In case of danger the chicks lay down on the round and because of the camouflage of their plumage become nearly invisible. Then adult birds run away from the chicks and draw attention to themselves, scream, pretend to be sick, sometimes even may pretend to have a fractured wing, dragging it along the ground and also limping. The predator being interested in the possibility of catching an easy victim usually follows it, forgetting about the chicks. When it is sufficiently far enough the adult bird suddenly takes up flight and returns to the nest.

Little ringed plover – a chick. Photo G. Leśniewski

Little ringed plover – a chick. Photo G. Leśniewski

Food
The plovers’ diet is dominated by various invertebrates: from spiders running around on beaches, beetles and other insects to insect larvae and earthworms living in oxbow lakes or on the banks of the river itself. Birds gather victims off the ground, sometimes chase after them, sometimes digging then out of the mud. The little ringed plovers can be noticed stomping while waiting for their victim, for example in order to flush them out from under some stones.
Plovers are very timid during rearing their young and if they are disturbed too often may even abandon the clutch and start its migration early.

Migrations
Normally plovers leave Poland in August or September, common ringed plovers winter in the Mediterranean Sea basin, while the little ringed plover flies markedly further to Africa.

Little ringed plover in flight. Photo M. Łukawski

Little ringed plover in flight. Photo M. Łukawski

Threats
Unfortunately, the breeding plovers on the Vistula are exposed to many dangers. Some of these are a result of the river’s characteristics, such as the nests may be flooded are as result of a sudden rise of the water level in the river. At the same time, the prolonged droughts are also not good for birds, because they cause the depletion of beaches, and hence the reduction of available food for birds.
Another problem is predators. Plovers’ natural enemies are foxes and ermines, although apart from those there are also stray dogs and cats, and American mink, which are an invasive species. Human activity is dangerous to this species, as beaches draw residents from neighbouring areas, who while are unaware of the birds’ presence may disturb them. Nests of plovers are very difficult to spot and so are easily crushed. Constant scaring off of adult birds, by walking, running, bike riding or worse, motorbike riding may result in them abandoning breeding.

Literature:
Chylarecki P, Sawicki G., Ostoja ptaków Dolina Środkowej Wisły, Wydawnictwo Askon, 2003.
Kot H., Dombrowski A. (red.). Strategia ochrony fauny na Nizinie Mazowieckiej, Mazowieckie Towarzystwo Ochrony Fauny, Siedlce, 2001.
Kruszewicz A.: Ptaki Polski Tom I., Warszawa, Wydawnictwo Multico, 2005 Svensson L.,
Ptaki Europy i obszaru śródziemnomorskiego, Multico Oficyna Wydawnicza, 2011.
Tomiałojć L., Stawarczyk T.: Awifauna Polski. Rozmieszczenie, liczebność i zmiany. Wrocław. Wyd. PTPP „pro Natura”, 2003.

The project ‘Protecting the habitats of priority bird species of the Vistula Valley under conditions of intensive pressure of the Warsaw agglomeration’ (wislawarszawska.pl) has received a grant from the Financial Instrument for the Environment (LIFE+) and from the National Fund for Environmental Protection and Water Management.