Numenius arquata Linnaeus, 1758

Birds live on average for 32 years and first start breeding when two years old.

• Attributions:

  1. Adapted from the Wikimedia Commons file "Image:Eggs Numenius arquat.jpg". Photo by Polarit, Tornio, Finland. Wikipedia, 3rd June 2006. Wikimedia Foundation, Inc. 30th August 2011.

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  A Eurasian curlew nest with 4 eggs that are greenish to olive-brown in colour, with dark spots or splotches of olive, reddish-brown or grey.

Nesting season: Eurasian Curlews lay their eggs between April and early July.

Nests: Either a bare scrape or a large depression in the ground, lined with dry grass and a few feathers, and, often situated on a tussock or low hummock, among grass or crops, or completely exposed in a meadow or similar habitat.

Sexual Behaviour: Birds show monogamous pair-bond, which is probably re-established annually. Both birds, but mainly the males, show territorial defence of nest site.

Clutch sizes: Vary between 2-6 in number. Optimal size is usually four eggs.

Egg description: Smooth and fairly glossy in appearance, the eggs are broad oval in shape, about 68mm long, greenish to olive-brown in colour, with dark spots or splotches of olive, reddish-brown or grey.

Incubation: Eggs are incubated for 27–29 days.

Hatching: Synchronous.

Parental behaviour: Several nests are bulilt by the male bird. The female only chooses one. Eggs are incubated by both sexes. Fledgelings are fed by both parents.

Fledgling: Chicks are precocial and fledge after 32-38 days or 5-6 weeks.

Juveiles: Are independent.

Survival rate: Due to their ground-nesting habit and the precocial nature of the chicks, Eurasian Curlews show high mortality rates. On average, about 66% of the birds die in the first year of their birth. The mortality rate reduces to 18% in the third year. This is mainly because they are vulnerable to predators like Foxes (Vulpes vulpes ) , Hooded Crows (Corvus corone) and Lesser Black-backed Gulls (Larus fuscus).

• Attributions:

  1. wildxplorer. --http://www.flickr.com/photos/krayker/3087839763/. Accessed on 2010-12-22.

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  Bird flock in flight.

A migratory species over most of its range, it is found wintering in Africa, southern Europe and southAsia. Occasionally, a vagrant individual reaches places far away from its normal range, such as in Nova Scotia or the Marianas. Usually found all year round in the milder climates of Ireland, Great Britain and the adjacent European coasts.

In India, it is chiefly a winter vistor. This is especially true for the race orientalis which is identified by its finely streaked underparts.

Lives for a maximum of about 31 years in the wild. The Eurasian Curlew first breeds when two years old, and the oldest known bird of this species lived for 32 years.

Length

From head to tail: 50-60cm on average.

Bill-length: 9-15cm on average.

Wingspan: 80-106cm on average.

Winglength:Males - 276-302mm, and females - 286-326mm on average.

Adult weight

Males 540-1000g, and females - 700-1300g on average.

The postnatal growth rate of this species is 0.13 days-1 (from logistic function).

Refer section on Diagnostic Description.

N. phaeopus , N.tahitiensis , N.americanus and N.madagascariensis.

Flying birds may resemble a Bar-tailed Godwit (Limosa lapponica) in winter plumage.

For distinguishing features, refer section on Diagnostic Description.

Most populations of the bird are fully migratory. In their winter grounds, they forage singly or in small groups, occassionally aggregating into flocks of several thousand individuals, especially at their roosting sites. Birds leave their wintering grounds around February to May, although non-breeders may remain in wintering grounds all year round. In the summer, usually between April to August, birds breed in solitary territorial pairs, occassionally forming small colonies. By July, birds gather on coast for post-breeding moult before they migrate south anytime between July - November.

Call: The familiar call from which this bird gets its name is a shrill, wild and plaintive scream of curloo or cur-lew, which is uttered chiefly on the wing.

Though very gregarious outside the breading season, this bird is usually exceedingly wary and difficult to circumvent.

• Attributions:

  1. Tarique Sani. -- http://www.flickr.com/photos/tariquesani/4329065559/. Accessed on 2010-12-22.

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  Eurasian Curlews feed by probing the wet sand on the banks of a water body or the shores of the sea at low tide or off the surface with their beaks.

Diet:

* In the non-breeding season, birds mainly eat small invertebrates including polychaete worms, molluscs, crustaceans (crabs), shrimps and amphipods; as well as earthworms, insects and spiders, small fish, amphibians, lizards, eggs and chicks , and small mammals like rodents. Studies suggest that in some parts of the world, like in Norway, earthworms may be the most important component of the diet of Eurasian curlews in the pre-breeding season. Occasionally, they also feed on berries and seeds of marsh plants, grass shoots, seaweed and other vegetable matter.

* On breeding grounds, they mainly eat insects and their larvae (e.g. Coleoptera and Orthoptera), especially grasshoppers and beetles, but also ants, craneflies, earwigs, flies and moths. They also eat annelid worms like earthworms, and occasionally freshwater crustaceans, amphibians, lizards, chicks and small mammals, and also occasionally fruits and other plant material.

Foraging:

Usually, the Eurasian Curlews feed by probing the wet sand on the banks of a water body or the shores of the sea at low tide or off the surface with their beaks. In general, they use the following 3 methods to forage:

(a)pecking the surface of the substrate

(b)quickly jabbing the bill into the substrate, inserting half of the length of the bill

(c)more prolonged probing, where the bill is fully inserted into the substrate.

Crabs are usually located by the birds by sight. Since curkews show sexual dimorphism in the shape of their bills, with males having shorter bills than females, both sexes show slightly different methods of foraging. Males tend to catch more invertebrates from the surface of the soil, while females tend to catch more earthworms taken from beneath the soil.

Predators: Foxes (Vulpes vulpes ) , Hooded Crows (Corvus corone) and Lesser Black-backed Gulls (Larus fuscus) feed on eggs, chicks and birds.

Prey: Insects and their larvae(e.g. Coleoptera and Orthoptera), especially grasshoppers and beetles, but also ants, craneflies, earwigs, flies and moths. Small invertebrates including polychaete worms, molluscs, crustaceans (crabs), shrimps and amphipods. Spiders, small fish, amphibians, lizards, eggs and chicks, and small mammals like rodents.

• Attributions:

  1. Gould, Birds of Great Britain, 1862 - 1873

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  A representative image of a Eurasian Curlew adult with fledgelings. Both parents share the responsibility of incubating the nest and feeding the young fledgelings till they become independent.

Eurasian Curlews are widely studied by evolutionary biologists in an attempt to understand the evolution of maternal desertion of young ones. This behaviour is frequantly seen in monogamous single-clutch shorebird species, of which Eursian Curlews are good examples.

It has been observed that both males and females of this species contribute equally to incubation. Also for a short period after the eggs hatch, both sexes show no difference in intensity in their mobbing behviour to protect their nests against potential nest predators. However, approximately halfway through the brooding period (16 days after hatching of eggs), females of the species have been frequently found to desert their offspring, while the males remain to rear the chicks to independence. Also, females that lay eggs later in the breeding season tend to leave their chicks sooner than those females that lay their eggs earlier in the breeding season. Thus, curlew females in North-Eastern Europe, where laying seasons were later, breeding seasons were shorter and migratory distances were longer than those females who were in Western and Central Europe, tend to desert their chicks much earlier than the others. Some studies have suggested that this behviour may have evolved as a result of the association of maternal desertion with increased female survival rates and the maintenance of pair-bonds between mating individuals between years.

Eurasian Curlews, along with other wading birds of the order Charadiformes, are also cited in evolutionary biology as an example of Adapative Radiation. "Essential Ornithology" by Graham Scott has one such description. He mentions how as many as a dozen species of birds of the Order Charadiformes can be seen feeding along the same area of a shore, but showing a wide range of bill morphologies, ranging from the tiny, straight bill of the Ringed Plover Charadrius dubius that is used to delicately isopods from the strand line, to the long decurved bill of the Eurasian Curlew Numenius arquata that is used to probe deeply into wet sand to drag out large polychaetes, to the heavy, hammering bill of the Eurasian Flycatcher Haematopus ostralegus that is ideal for smashing open the shells of bivavle molluscs. Scott hypothesises that this diversity of bill shapes and sizes allows the birds to co-exist without competing too closely for food - each bird species occupies it's own unique feeding niche. He suggests that this diversity in bill morphology may be an example of one visible outcome of a process of adaptive radiation. It is likely that at one time, the Charadiform bill was more or less uniform, but through evolutionary time and in parallel with the evolution of all of the various wader species, it evolved into many different forms as a result of natural selection.

A list of nucleotide sequences from the Eurasian Curlew can be viewed at: http://www.ncbi.nlm.nih.gov/nuccore?term=Eurasian%20Curlew

A list of protein sequences from the species can be viewed at: http://www.ncbi.nlm.nih.gov/protein?term=Eurasian%20Curlew

In a survey of H5N1 Avian flu virus in wild birds in 14 provinces of China from 2004-2007, samples of the virus were collected from Numenius arquata where the prevalence of infection was estimated to be 0.40%.

A study on the laterality of wildfowl and wading birds while they were performing the single task of roosting on the ground on one foot indicates that Eurasian curlews may be right footed.

Includes the following: fresh and saltwater marshes; rocky beaches with tidal pools; mudflats, estuaries and sandy shores; and, heath, moorland and fields near water.

In general, during the breeding season, birds are found on upland moors, peat bogs, swampy and dry heathlands, fens, open grassy or boggy areas in forests, damp grasslands, meadows, non-intensive farmland in river valleys, dune valleys and coastal marshlands. Whereas in non-breeding seasons, species frequents muddy coasts, bays and estuaries with tidal mudflats and sandflats, rocky and sandy beaches with many pools, mangroves, saltmarshes, coastal meadows and muddy shores of coastal lagoons, inland lakes and rivers.

Being a palearctic migrant, a few birds may over-summer. 

Description

Enumerates geographic entities where the taxon lives. Covers ranges, e.g., a global range, or a narrower one; may be biogeographical, political or other (e.g., managed areas like conservencies); endemism; native or exotic. Does not include altitudinal distribution, which is covered under Habitat.

Contributors	Chitra Ravi, Content Editor, India Biodiversity Portal
Status	Under Creation
Audiences	General Audience
Licenses
References	IUCN 2011. IUCN Red List of Threatened Species. Version 2011.1. . Downloaded on 30 August 2011. BirdLife International (2011) Species factsheet: Numenius arquata. Downloaded from http://www.birdlife.org on 30/08/2011.  Numenius arquata — Eurasian Curlew'. Biodiversity Species Profile and Threats Database. Australian Government, Department of Sustainibility, Environment, Water, Population and Communities. Last updated: Monday, 06-Dec-2010. Accessed on: 30th August 2011.

No.

This species has a large range, with its estimated global extent of occurrence being about 10, 000, 000 km2; and large global population of about 770,000 - 1,065,000 mature individuals. This number is now believed to be decreasing, especially in Europe.

According to BirdLife International, there was an estimated three-generation decline of 26.1-34.1% of the species in 2007. However, because there is a certain degree of uncertainity regarding whether decline in southern populations of the species have been compensated for by increases in northern populations, the global trend of Eurasian curlews is suspected to fall within the band of a 20-30% decrease in the past 15 years (three generations).

Red List Category & Criteria: Near Threatened

Year Assessed: 2008

Assessor/s: BirdLife International

Reviewer/s: Bird, J. & Butchart, S. (BirdLife International Red List Authority)

Breeding:

On the breeding grounds, especially in Europe, Eurasian Curlews are adversely affected by loss, fragmentation or modification of their breeding habitats as a result of afforestation or agricultural intensification and improvement (e.g. drainage, inorganic fertilisation and reseeding). This includes the drainage of wet grasslands, moors and peat bogs, conversion of such habitats to farmland or forested areas, intensive management of habitats for game or intensive grazing. In addition, they have also been threatened by technology. Mechanized cutting of peat, and mowing of grassy areas causes high mortality of chicks and eggs. In contrast, in the Central Asian Steppes, populations have declined following abandonment of farmland and subsequent increases in the height of vegetation, rendering large areas unsuitable for nesting. Hunting and the susceptibility of the species to avian influenza virus are two other threats to the survival of the bird.

Non-breeding:

Wintering populations are threatened by disturbance on intertidal mudflats (e.g. from construction work and foot-traffic), development on high-tide roosting sites, pollution and the flooding of estuarine mudflats and saltmarshes as a result of tidal barrage construction. Also threatened by the degradation of migrational staging areas owing to land reclamation, pollution, human disturbance and reduced river flows. Local populations of this species have also declined owing to hunting pressures.

Others:

Many threats that affect all migratory waders occur in the East Asian-Australasian Flyway. These include:

1. Direct and indirect habitat loss. Staging areas used during migration through eastern Asia are being lost and degraded by reclaiming of mudflats for future development, or, by the rapid rate of reclamation of many inter-tidal areas along the East Asian-Australasian Flyway.

2. Infastructures for regulation and diversion of water bodies in the major tributaries. These reduced water and sediment flows.

3. Global warming and associated changes in sea-level. These are predicted to have long-term impacts on the breeding, staging and non-breeding grounds of migratory waders.

4. Increasing pollution, and disturbance from human activities - including recreation, shellfish harvesting, fishing and aquaculture.

International: Listed in the Agreement on the Conservation of African-Eurasian Migratory Waterbirds(AEWA), Appendix II of the International Convention on Migratory Species, Marine and Migratory under the Environment Protection and Biodiversity Conservation Act 1999. (Australia), Migartory Bird Treaty Act, and, in the China-Australia Migratory Bird Agreement (CAMBA).

Eurasian curlews occur in a large number of protected areas throughout its range and feature in several national monitoring schemes.

The European Commission has commissioned a management plan for species that are listed in Annex II/2 of the EU Birds Directive. This plan has been updated for 2007-2009, and outlines the following key conservation targets: 1. Protect key wintering sites.

2. Determine the key perameters driving declines in breeding areas and integrate agri-environment measures to counter these.

3. Continue monitoring trends.

4. Minimise disturbance on the wintering grounds.

Early scientific descriptions of the Eurasian Curlew:

Murray, James A. (London : Trubner, 1888-1890) in his book "The avifauna of British India and its dependencies." describes Eurasian Curlews in the following words - "Habitat. Throughout most parts of Europe, India, Burmah, Ceylon, N. Africa, Egypt, Abyssinia and Palestine. Common along the sea coast and backwaters in great numbers during winter; also along the banks of the Indus and Punjab rivers, and on all large inland sheets of water."

Jerdon, T. C. (Thomas Claverhill) in his book "The birds of India." (Calcutta, 1862.Vol 2,2.Pg:684) describes Eurasian Curlews in the following words - "The Curlew is found throughout India, most abundantly perhaps near the sea coast, but also far inland, frequenting marshes, lakes, and rivers. It is generally seen in small flocks, often alone, but at the times of its arrival or departure sometimes in great numbers. It arrives in September and leaves in March or April. It is a very wary bird, and has a fine wild whistle. It is excellent eating. It breeds in Northern Europe and Asia (spreading in winter into Africa and Southern Asia,) laying four eggs of the usual blotched green colour. The Curlew is stated to perch on trees occasionally in Northern Europe."

Different usages of the word 'Curlew':

The word Curlew is used in many different contexts, listed in Webster's Online Dictionary at: http://www.websters-online-dictionary.org/definitions/Curlew.

Poetic usages of the word 'Curlew':

The word Curlew has been used by some poets in their verses. Examples of some of these poems can be seen in Webster's Online Dictionary at: http://www.totopoetry.com/PoetryForWebstersOnlineCombined.asp?word=Curlew&ip=115.241.92.42#1

Bamford and colleagues (2008) have reviewed sites of international importance for migratory shorebirds across the East Asian-Australasian Flyway to assist in management decisions related to species such as the Eurasian Curlew. This review can be found at: http://www.environment.gov.au/biodiversity/migratory/publications/shorebirds-east-asia.html

One study into the effects of shellfish harvesting by hand in coastal intertidal habitats recommends that the harvesting load should be limited to <0.56 persons per 10 ha-1 during the Eurasian Curlew's autumn migration. Another study indicates that disturbance of mud in inter-tidal habitats by harvesters working by hand did not affect mean density of curlews, their foraging activity, feeding rate, percentage of crabs in the diet, size of crabs, or foraging speed. The latter study suggests a compatibility between shorebird conservation and traditional low-tide clam harvesting.