EURASIAN CURLEW (Numenius arquata)
The Eurasian Curlew is a medium-sized bird, the largest representative of the Scolopacidae family. It is slightly larger than the Carrion Crow, but smaller than the Common Raven. The colors of the plumage are subdued. The top of the body is grayish-brown, hatched and striped. In flight, the white wedge on the rump, dark stripes on the light-colored tail and uniformly dark wingtips are clearly visible. The underside of the body is lighter with lots of white with brown speckling. A distinctive feature is the exceptionally long and downward curved beak. Its length can be up to 16 cm. Its legs are also long, allowing it to wade through water and mud. Males and females are of identical colors, however, the females are larger and have longer beaks, making it easy to tell them apart when the birds are standing next to each other in a pair. Males weigh an average of just over 700 g, while females weigh 900 g.
The Curlew's vocalization is very distinctive, somewhat melancholic but pleasant sounding and its sound can be described as ‘coo-lee’. During courtship, males soar high and then in descending gliding flight perform a flute-like song that is initially slow, but later increases in tempo and turns into a dynamic and loud tune.
BREEDING BIOLOGY
The nest is a shallow pit in the ground, lined with dry plant fragments, grass blades or straw. It is usually located among vegetation, but can also be built on bare ground if Curlews nest on arable land. The main breeding season begins in mid-April and lasts until early May. A typical clutch consists of 4 spotted, greenish or olive-colored eggs, which are laid 1–2 days apart. Eggs are brooded alternately by both parents for about 28 days.
Chicks are nidifugous, meaning that soon after hatching they leave the nest and are able to forage for food on their own. Despite their great independence, the young Curlews still need care for a long time. Their parents point them to places abundant in food, alert them to approaching danger and defend them from predators. Females leave their offspring early, while males stay with their young until they learn to fly. In the early stages of life, Curlews face numerous dangers, so only a few survive.
The Eurasian Curlew feeds primarily on invertebrates. In search of earthworms, it penetrates soft and moist soil. On the surface, it grabs insects, both larvae and adult forms, and spiders. It occasionally catches small vertebrates, frogs, lizards and rodents. It supplements its diet with plant food. It collects seeds and small fruits. With its long beak, it can also search for food underwater, which it often does on coastal wintering grounds.
HABITATS
In Poland, the Eurasian Curlew occurs mainly in river valleys, in the valleys of smaller watercourses and in damp depressions of land. It generally avoids areas close to forests or with a high proportion of trees and shrubs. It inhabits vast open areas because good visibility allows it to quickly detect danger from predators. It prefers well-humidified, extensively used meadows and pastures, but sometimes nests in more intensively used areas and arable land.
The Eurasian Curlew, compared to other Charadriiformes, has large spatial requirements. One bird can use more than 100 hectares of foraging grounds during the breeding season. Important for it are organic soils — peat soils and river fluvisols. Extensive permanent grasslands on this type of soil are abundant in food and provide a rich foraging base. Due to its high habitat requirements, the Eurasian Curlew is found only in certain parts of Poland. Currently, the most important breeding areas are the valleys of large and medium-sized rivers: Noteć, Warta, Ner, Bug, Wkra, Omulew and Biebrza and its tributaries. Other, also large, open areas such as: Wielki Łęg Obrzański riparian forest i in western Poland, Pulwy Marsh in central Poland, and Wizna Marsh and the "Żelizna" meadow complex in the eastern part of the country.
Before 2000, the population of the Curlew in Poland was estimated at 650–700 breeding pairs. It is currently estimated at only about 200 pairs. Due to this drastic, multi-year decline in numbers, the species is considered endangered in the country (Polish Red List of Birds 2020). Thanks to the measures taken, the unfavorable trend has been stopped and the population has been stabilized, but its recovery requires further conservation efforts.
THREATS
Predation
The most important threat to the eggs and chicks of the Eurasian Curlew is predation. Eurasian Curlews sometimes manage to chase away some predators and protect their nests. Unfortunately, they don't stand a chance in case of more predators or if the predators are bigger and stronger than the Curlews. Nests are robbed mainly by predatory mammals (foxes, raccoons), but also by Corvids (Common Raven, Carrion Crow). Birds of prey such as buzzards and harriers may also prey on chicks and fledglings. Sometimes wandering dogs and cats are a threat. Sometimes adult birds are caught by predators while brooding in the nest.
Agrotechnical operations
A very serious threat to Curlews is agrotechnical operations carried out during the period when the birds are brooding eggs or raising young chicks (from mid-April to early July). Fertilizer or slurry spreading, harrowing, rolling or mowing pose a danger to birds. During such operations, Curlew nests are inadvertently run over and destroyed. Young birds and flightless chicks are also killed, whose instinct, in the face of danger, tells them to stand still and trust the camouflage coloration of their plumage.
Weather conditions
Heavy rains during the breeding season can lead to nest flooding and abandonment by adult birds. Prolonged precipitation is also dangerous for chicks, often causing them to die from hypothermia.
Scaring birds away
Unintentional scaring away is very often caused by people (farmers performing agrotechnical operations, fishers, tourists, hikers, etc.) and pets, primarily running dogs. When adult birds are scared away, they leave their nest, as a result of which unprotected eggs or even chicks become easy prey for Corvids — Crows and Ravens. These intelligent birds are keen to take advantage of the absence of adult Curlews near the nest.
Habitat changes
Reconciling agricultural development, associated with its intensification, and the protection of birds of the agricultural landscape is a difficult but necessary challenge of our time. Some of the permanent grassland in the breeding habitat of the Curlew is being converted to arable fields — including corn fields. Meadows are overproduced by repeated fertilization and slurry spreading during the growing season. Intensively used grasslands are being turned into single-species grass crops. Such transformations make the structure of vegetation simplified, as the number of species decreases. Attractive places to establish and hide nests are lost. The diversity of invertebrates, which are the Eurasian Curlew's main food source, is diminishing. Transformed and intensively used agricultural land is also easier for predators to penetrate.
Regulating watercourses, filling in natural depressions in grasslands, strengthening river banks, and drainage improvements (deepening drainage ditches and digging new ones) are treatments that also negatively affect the quality of the Eurasian Curlew's habitat. Such activities lower the water level in the soil and thus make it more difficult for Curlews to access food, and also affect the vegetation and impoverish the invertebrate fauna.
The Black-Tailed Godwit, Redshank, Lapwing and Common Snipe are species related to the Eurasian Curlew, which are sometimes its frequent neighbors. Shorebirds, as this group of birds (Charadriiformes) is commonly called, readily nest in mixed groupings. These number from several to a dozen pairs, and even more if habitat conditions are attractive. Charadriiformes’ nests are shallow holes, hidden among clumps of grass or sedges. Colony nesting is a strategy for defending nests and chicks from predators. It is easier for a large group of birds to spot and chase away an intruder (e.g., fox, Carrion Crow) with joint efforts.
Black-Tailed Godwit (Limosa limosa)
A long-legged, slender bird, with a very long straight beak. In the mating colors, the neck and front of the chest are rusty red, and the belly is bright with dark transverse stripes. Its beak is orange with a black tip, and the legs — dark gray. In flight, a white stripe on the wings and a white tail with a wide black stripe at the end is visible.
The Black-Tailed Godwit inhabits alluvial meadows and pastures in river valleys, marshy meadows surrounded by lakes, ponds and lagoons, less frequently drained fish ponds and reservoirs. It arrives on the breeding grounds from mid-March to April, and departs from July to August. Its numbers have declined dramatically in recent years and it is considered a critically endangered species in the country.
Northern Lapwing (Vanellus vanellus)
A bird the size of a pigeon, with a distinctive raised tip on its head and broad wings rounded at the tips. Its throat and top of the head are black, and the belly is white. The back in the male has a greenish sheen. Its tail is white with a black stripe at the end.
The Lapwing inhabits wet and marshy meadows and extensively used pastures in the valleys of large rivers, as well as arable fields with spring grain, drained fish ponds and reservoirs. It arrives on the breeding grounds as early as late February/early March. Leaving the nesting area occurs after the young have been raised, i.e., from late May to July. Nomadic flocks of Lapwings are encountered as early as June, with the last departing birds still seen in November.
The Lapwing is observed less and less frequently in meadows and fields. Monitoring of Common Breeding Birds (orig. Monitoring Pospolitych Ptaków Lęgowych) revealed that during the 23 years of data collection (2000–2023), its population decreased more than threefold!
Common Redshank (Tringa totanus)
A medium-sized Charadriiform with long legs, a long beak and an elongated neck. In its mating colors it is gray-brown. The underside of its body is whitish, but covered with dark longitudinal stripes. Legs are bright red, very shiny in summer. The beak is straight, red at the base with a blackish tip. In flight, the white lower edges of the wings are visible, as well as a white wedge in the lower back and on the rump. Tail in dense, dark, transverse stripes.
It inhabits extensively grazed pastures, where a characteristic tufted vegetation structure develops. It also nests on islands in the beds of large rivers. The nest of the Redshank is often located in rank grass. To further camouflage the nest, a brooding bird pull tips of grasses growing within beak range over its head and back. It arrives on the breeding grounds in March and flies away between July and August. It winters on coasts in western Europe and Africa.
Common Snipe (Gallinago gallinago)
A bird the size of a Blackbird, with a stout body, short legs and a very long straight beak. The camouflaging coloration is dominated by rust-brown colors. The back is clearly “scaled”. A white stripe passes through the center of the head (fonticulus). When in danger, it crouches on the ground and dashes off rapidly at close range calling out “kshsh-kshsh” several times. It then soars diagonally in a zigzag flight.
It inhabits marshy meadows, old river beds and marshes. It usually hides its nest well in a sedge or grass tufts. Sometimes it is surrounded by water. Near the nest, it likes to sit on higher places, on pasture fence posts, dry trees, and concrete poles. It arrives on the breeding grounds as early as March. It departs for its wintering grounds from July to September.
CURLEW AS AN UMBRELLA SPECIES
The Curlew is a rare species with a very characteristic appearance, closely associated with specific habitats - large open areas of wet meadows, and its protection requires securing large areas. This makes it an excellent umbrella species. Active species protection project focus mainly on protecting their habitats. Therefore, by protecting the Curlew, we protect the entire ecosystem - a set of animal and plant species found in wet meadows. Actions aimed at ensuring optimal water conditions by retaining water in the habitat are particularly important here. Therefore, other species of waders - Black-tailed Godwit, Redshank, Lapwing, and Snipe - will benefit from active protection of the Curlew. Delaying mowing will be important for the preservation of many species of insects and amphibians inhabiting wet meadows. In other words, such an area will become more attractive to more species, which means an increase in biodiversity.
How can I help Curlews and other shorebirds?
Steering away from their nests in meadows
If you have found a Curlew, Black-Tailed Godwit or Lapwing nest in your meadow, mark its location. Do it with two sticks that are not tall and unobtrusive. They should be thin, otherwise they can be used as a lookout by Corvids and birds of prey. Hammer them at a distance of 2–3 m on either side of the nest, so that they are visible when conducting agrotechnical operations. With the markings, you will be able to steer away from the nest and thus save the breeding birds. Remember, the larger the patch of unmowed vegetation you leave around the nest, the lower the risk that a predator will destroy it.
Delaying the mowing of meadows
The first Curlew chicks hatch as early as mid-May, and peak hatching continues until the end of the first decade of June. At this time, many farmers begin haying. If you have found a Curlew, Lapwing or Black-Tailed Godwit nest in a meadow, or know that these birds are present in the meadow, postpone mowing to a later date if possible. Sometimes a few extra days will significantly increase the chicks' chances of survival.
Starting mowing meadows from the center
This mowing technique reduces the risk of inadvertently killing chicks. The chicks flee towards unmowed patches of vegetation, moving gradually outside the plot to a safe place where they can hide in a neighboring plot, a ditch or bushes.
Preserving breeding and feeding habitats
Eurasian Curlews often feed in shallow floodplains that form in meadows after the spring melt. By preserving the natural terrain in river valleys, any irregularities in meadows and pastures, you protect not only the feeding grounds of Charadriiformes, but also the White Stork and amphibian breeding sites.
By retaining water in the soil
Repeated droughts in recent years have caused heavy losses in agriculture and have had a devastating impact, including on Charadriiformes. Properly functioning drainage systems should allow not only the drainage of excess water during farming on meadows, but, more importantly, retain it in the habitat outside this period. By collecting water in ditches in the spring, you help protect birds and reduce the economic losses associated with drought. For this purpose, use the existing damming devices by installing stoplogs, and in their absence, block the outflow of water, such as with sandbags.
Contacting a specialist ornithologist
All of the above protection methods should be consulted with a specialist and carried out under the supervision of an ornithologist, only then can we ensure a high likelihood of breeding success. If you know or suspect that Curlews or other Charadriiformes may be nesting in your meadow, please contact us or another ornithologist. Together we will figure out a way to save the breeding grounds of these rare birds, so that their protection is not a nuisance for you. In the case of the Curlew, we can help by fencing the nest with an electric shepherd to help protect the nest from predators. Remember that the Curlew, Black-Tailed Godwit, Redshank or Lapwing are desirable guests for farmers! Their presence in meadows or pastures qualifies permanent grassland for agri-environmental subsidies. Find out more at the Agricultural Advisory Center or the Agency for Restructuring and Modernization of Agriculture.
