Oriental Curlews in Western Europe: identification and status
Eurasian Curlews are widely distributed across temperate Europe and Asia, ranging from the British Isles to Far Eastern Asia. While some populations are mostly sedentary, others undertake long-distance migrations and, in winter, they can be found throughout Africa and South Asia. In the literature, three subspecies are commonly recognized:
arquata, found in the western part of its range;
orientalis, inhabiting the eastern part of its distribution; and
suschkini, a southern population that breeds in the steppes of Kazakhstan.
Within the birding community, orientalis is generally considered a taxon exclusive to Far Eastern regions and, to the best of our knowledge, has not been officially recorded in western Europe. However, the scientific literature states that most of the Curlews wintering in Africa actually originate from Central Asia. Therefore, the presence of Curlews of eastern origin in Europe might be plausible, at least as vagrants. Motivated by this hypothesis, we have conducted studies on Eurasian Curlews in Spain over the past three years, documenting several birds exhibiting orientalis-like characteristics. Our findings indicate that while these birds are scarce, they do appear regularly as migrants in Western Europe.
The purpose of this post is to describe the occurrence of orientalis in Western Europe, detailing the phenotypic features and migration patterns of the Asian birds that follow the “western” migratory route. In order to gain a comprehensive understanding of the global patterns of geographical variation and migration among different populations, we have extensively researched online resources to supplement our field studies conducted in Europe and Northern Africa.
Two initial considerations
A note on ageing (European) Curlews
Ageing Eurasian Curlews, as well as Whimbrels, can be more challenging compared to other shorebird species due to the similarities in the appearance of juveniles and adults. During summer and early autumn, it is generally easier to determine the age as juveniles exhibit a pristine and freshly grown plumage. However, as the season progresses, it becomes more complicated to age them due to wear and variations in bill development. Some juveniles even start their southbound migration before completing their bill development, resulting in the presence of individuals with shorter bills at their wintering sites. In Eurasian Curlews, there are some key plumage differences that aid in age determination when observed closely:
Tertial pattern: Adults display narrow, dark shafts with very fine barring in their tertials, whereas juveniles exhibit broader dark feather centers, often with a sawtooth pattern.
Breast/flank spotting: In adults, the breast pattern typically consists of arrow-shaped or anchor-shaped markings, particularly in the lower breast and flanks. In juveniles, the spots tend to be finer and more drop-shaped.
Shape/wear of outer primaries: As in many other birds, juvenile primaries tend to be of less quality than those of subsequent generations, and if seen well the presence of worn and brownish, pointed primaries is a good sign of a first year bird.
First-year Curlews in Europe undergo a partial moult during autumn and winter, which involves the replacement of head and body feathers, mantle, and sometimes even tertials. Since Curlews do not breed until their third or fourth year, many young Curlews remain in their wintering locations during their first and second years of life. These young birds begin their primary moult in early spring (April/May) and complete their first moult by summer. Adults also undergo a moult in the wintering locations after their post-breeding migration, typically commencing their primary moult in mid-summer (end of June/July) and completing it before autumn. There is still lots to understand about the moult of Curlews in the Southern Hemisphere, but preliminary evidence suggests that birds wintering in Africa and SE Asia may show a variety of moulting strategies differing from European birds, including for instance a primary moult in winter of 1w birds or an eccentric moult of primaries.
Figure1. European Curlew ssp arquata, juvenile, Basque Country, Spain, July 2023 (David Santamaria). Ageing as juvenile is straightforward based on very fresh plumage, dark-centered wing coverts and tertial pattern - note also that the bill is likely not fully grown. The breast and flank pattern, lacking any arrow, is reminiscent of orientalis, although in juvenile arquata the spotting is denser, the spots have a more drop-like shape (rather than a fine streak in orientalis) and the background colour is typically buffy.
Figure 2. European Curlew ssp arquata, juvenile, October, Galicia, Spain (Ramsés Perez). The breast pattern of this bird is reminiscent of orientalis, but the overall coloration is quite brown and the head shows a marked cap.
The mystery of suschkini
After reviewing all the literature available and assessing how the published information fitted within, we have finally decided to exclude suschkini from this post. According to the literature, this taxon is described as similar to orientalis but much smaller in size, approaching that of a Whimbrel, with a much shorter bill than the other taxa. It is believed to overwinter somewhere in Western or Central Africa. Delany et al. classified suschkini as an endangered taxon with an estimated population of only 1.220-2.170 pairs (in 2006).
During our research, we have seen a couple of orientalis-type Curlews considerably smaller than the average size for this subspecies in Spain, plus at least two more in Western Sahara. These birds showed an overall pale appearance with a contrasted dark above / pale below plumage, and very short and thin bills - even reminiscent of what Slender-billed Curlew might have looked like. Sadly, only poor record shots were obtained, which prevented any further study.
Due to the limited knowledge we have about this taxon and its extreme rarity, if it still exists at all, we consider that further research is necessary, including field studies in Northern Kazakhstan and the wintering grounds in Africa, as well as a detailed study of museum specimens. At this point, it remains a mystery to us whether suschkini represents a distinct taxon, clearly differentiated from orientalis, or if it represents the southern end of a clinal variation in size. Hopefully, this post will raise awareness about the status of Curlews of Asian origin in Europe and Africa, and prompt further investigation that could shed light on suschkini, much like the re-discovery of the Steppe Whimbrel in Mozambique a few years ago!
Identification
Separation of arquata and orientalis
The identification of arquata and orientalis has been extensively discussed in the literature (e.g., Corso et al., 2014). In this review, we will highlight the main identification features, particularly those that are prominent when both subspecies are observed side-by-side.
Overall coloration: the differences in plumage colour are often striking, with orientalis appearing much paler than arquata. In fact, the contrast is often so noticeable that these birds can be distinguished with the naked eye. arquata typically exhibits a brown colouration, while orientalis has an almost grey appearance.
Bill: on average, orientalis have longer bills, with some females even displaying incredibly long bills that give them a distinctive appearance. In general, the bill of orientalis is straight at the base and curves downward at the tip, whereas in arquata, the bend tends to be more gradual. There is, however, considerable overlap, especially considering that males in both subspecies have much shorter bills than females. Consequently, male orientalis exhibit shorter bills than female arquata. In addition to length, orientalis displays on average more pink, starting at the base and extending onto approximately half of the total bill length, sometimes even reaching the upper mandible.
Tibia length: based on our field observations, orientalis may have longer tibias, resulting in a long-legged appearance, especially evident in side-by-side comparisons. orientalis also tends to be slightly larger overall, and when combined with its pale coloration, these individuals often stand out when observed within a flock of arquata.
Breast spotting: arquata usually exhibits a coarse spotting on a pale brownish background. In the lower breast, the spots increase in size and gradually transform into anchors. In orientalis, the spotting is more sparse, with fine streaks instead of distinct spots, and the breast background is paler, sometimes nearly white. While the spotting in most arquata extends to the mid-belly or even further, in orientalis it is usually restricted to the upper breast. As mentioned earlier, the classic orientalis pattern is not uncommon in some juvenile arquata, so accurately determining age is critical. When observed closely, the pattern also differs, with arquata juveniles exhibiting elongated spots that still retain a drop-like shape, rather than a streak of uniform width. Additionally, the background colour of the breast of these confusing juvenile arquata appears brownish or sandy rather than white.
Flank pattern: arquata typically features heavily marked flanks with thick arrow-shaped patterns. In the least patterned individuals, the arrows may be limited to an area visible only in flight, just below the axillaries, requiring careful scrutiny. In contrast, classic orientalis shows no arrows or, at most, a few very narrow ones, with sparse streaking instead (but there is some variation).
Underwing: orientalis consistently exhibits a white underwing, whereas there is some geographical variation in the underwing pattern of arquata across its range, as discussed below. Generally, Western European arquata tend to show at least some patterning, primarily as arrow-shaped spots, on the underwing.
Head: orientalis sometimes shows a very pale head, lacking the typical dark brown cap of arquata. The entire head looks more uniform, with a less-contrasted supercilium.
Wing-scapulars contrast: in typical orientalis, the wing coverts usually show nearly white fringes, and thus the wing looks pale grey at a distance. In flight, the wings often show a marked contrast with the browner scapulars. This pattern can be striking in many orientalis but is sometimes shown in some arquata too, so it should not be considered as a diagnostic feature.
Primary pattern: the barring in the inner primaries, likely associated with the overall paleness of the bird, sometimes differs between the two subspecies - but this is the most variable character and only strikingly different in a few orientalis. arquata displays darker primaries, typically with brown feathers featuring 6-8 pale triangles on the inner web. In orientalis, the pattern appears almost the opposite, with broad pale triangles separated by narrow dark lines. They usually have more of these triangles, ranging from 8 to 12. Corso et al. (2013) described the difference in the pattern of the outer 2 primaries, barred in arquata and dark in orientalis.
Tail: as with the inner primaries, the tail sometimes looks very pale in some orientalis as a result of the fine barring.
Figure 3. Key plumage features relevant for the separation of arquata and orientalis (see the main text for further details). 1. axillaries and underwing; 2. head; 3. tail barring; 4. flank pattern; 5. breast spotting; and 6. inner primaries barring.
Figure 4. Oriental Curlew ssp orientalis, July, Malaysia, (left, Dave Bakewell) and (right) (Chris Gibbins). Eastern orientalis are quite pale grey, large and especially long-billed. Note the fine and sparse streaking (rather than spotting) on the breast on a white background. The streaking is usually restricted to the breast and limited/absent on the belly, leading to a very pale upperparts. Note also poorly marked head pattern, lacking a darker cap.
Main plumage types across Eurasia
Understanding the geographical variation of Curlews is a challenging task due to limited information from their breeding grounds in Asia. However, with the increasing availability of online photographs, we can draw some preliminary conclusions. Based on our current understanding, both arquata and orientalis are well-differentiated but still present some geographical variation within their respective range, including an extensive region of intergradation occurring in western Siberia, possibly between the Urals and Central Asia. Four main phenotypes can be identified:
Atlantic [western arquata]: Curlews breeding in the British Isles & Atlantic Europe tend to be the darkest and most patterned, with many individuals displaying dense arrow-shaped patterns on the belly, flanks, and heavily barred underwings. In contrast, Curlews from Eastern and Baltic Europe appear paler and exhibit white underwings more frequently. British Curlews are predominantly sedentary, and only a small proportion of the Curlews wintering in Atlantic Iberia belong to this type. They seem to be absent from the Mediterranean region.
Continental / European [eastern arquata]: the majority of European arquata exhibit limited barring on the underwing (and all-white underwings are not rare at all), but they do display a brownish breast with arrow-shaped patterns on the breast and flanks. These birds are mostly sedentary or undertake short-distance migrations. They reach the Iberian Peninsula and Morocco in relatively low numbers (less than 10,000 birds) compared to the entire European population of approximately 700,000 birds (Delany et al., 2009).
Central Siberian [western orientalis]: birds displaying features suggesting intergradation can be observed in the Eastern Mediterranean, Africa, and India. These individuals resemble typical orientalis, but they tend to be slightly browner and may have a few anchor-shaped patterns on the flanks, which are often visible only in flight. They also exhibit intermediate characteristics in terms of body structure and bill length.
Oriental [eastern orientalis]: these are the largest Curlews with the longest bills. They appear pale grey and show minimal streaking below, rarely exhibiting any solid anchor-shaped patterns on the flanks. Oriental Curlews are predominant in Southeast Asia, but perfectly looking orientalis are not uncommon in Africa, including the Western Sahara. Some of the birds seen in the Iberian Peninsula closely resemble typical Oriental birds.
Figure 5. Proposed ranges for all four plumage types. A: ‘Atlantic’ Curlew (W arquata); B: ‘Continental’ Curlew (E arquata); C: ‘Central Asian’ Curlew (intergrades and W orientalis); D: ‘Oriental’ Curlew (E orientalis). Information about Eastern taxa breeding grounds is limited, so the depicted ranges here are approximate. The enigmatic suschkini race is not included but is believed to breed mainly in Northern and Central Kazakhstan; winter range unknown. Adapted from Van Gils, et al. (2020).
Figure 6. Variability of the underwing, flanks and breast pattern in the four main phenotypes of Eurasian Curlews found across Eurasian. For each group we have included three representative examples, but there is some variation and, for instance, some Continental Curlews may show patterned underwings within the range of Atlantic (a-c). As a general rule, the four groups can be separated by the extension of spotting in the underparts (from right to left, E to W): in Oriental it is restricted to one third (upper breast, the rest are neat white); in Central Asian, around one half; in Continental arquata, c. two thirds; and in the Atlantic birds the spotting nearly reaches the vent, > ⅔. This is of course a broad characterization, not to be applied to the identification of individual birds. Pictures by Zbigniew Kajzer, Andrew Spencer, Peter Alfrey, Chris Gibbins, Marcel Gil-Velasco and Guillermo Rodríguez.
Figure 7. European Curlew ssp arquata, Atlantic-type, January 2023, Cantabria, Spain (Guillermo Rodríguez). West European Curlews are often very dark, with a broad and dense patterning on the breast that extends down towards the lower belly, with bold anchors well visible when resting. The underwing is variable but birds with barred underwings are common.
Figure 8. European Curlews ssp arquata, Continental-types, adults, Santoña marshes, January 2023 (Guillermo Rodríguez & Kike Junco). European birds are overall brown, although the level of patterning is variable. The breast spotting is coarse and on a brownish background; the spots transform into arrows on the flanks. Note the finely barred tertials and wing coverts, diagnostic of adult birds. In some (more eastern?) birds, such as the one on the right, the arrows are more restricted and only visible in flight; note also a finer breast spotting and paler coloration than in the previous birds.
Figure 9. Oriental Curlews ssp orientalis, India, juvenile (left) and adult female (right), (Savio Fonseca / www.avocet-peregrine.com). Many of the Curlews seen in India look like perfect Eastern orientalis, likely indistinguishable from the birds wintering in Southern Asia. These two birds look a bit browner overall, but the effect of wear often affects the general coloration. In addition to the plumage features, note long bill with extensive pink and long tibia.
Figure 10. Central Asian Curlews ssp orientalis / arquata, India (Aseem Kothiala). Most Curlews wintering in India may be Central Asian, looking browner, with shorter bills and thicker spotting on the breast than SE Asia birds. Birds with some arrows on the flanks are not rare, and some extreme birds such as the one on the right superficially resemble arquata in general aspect (two more examples here and here).
Figure 11. Examples of Oriental Curlews ssp orientalis from Africa: (left) South Africa: adult, Nov (Trevor Hardaker) and (right) Senegal, April (Daniel López-Velasco). Curlews that overwinter in South Africa typically look like eastern orientalis. As one travels north and west towards the Gulf of Guinea and Western Africa, there seems to be more mixing, with both western and eastern orientalis-types. Still, many birds look quite classic and probably not separable from those wintering in SE Asia - the bird on the right from Senegal is a particularly striking orientalis.
Figure 12. Central Asia Curlew, ssp orientalis, Western Sahara, March 2023 (Marcel Gil-Velasco). A typical western-type orientalis, showing some features suggesting arquata-influence: despite the lack of arrows on the flanks, the breast spotting is a bit thick, and the bird is quite brownish.The neat underwing, pale and finely barred primaries and pale tail are however typical of orientalis. These birds show on average shorter bills than eastern orientalis.
Figure 13. Central Asia Curlew, ssp orientalis, Western Sahara, March 2023 (Marcel Gil-Velasco). A more classic orientalis from the Western Sahara, ticking all the boxes for a very eastern bird.
Figure 14. Central Asian Curlew ssp. orientalis, first-winter, Ebro Delta, Catalonia, Spain, February 2023 (Marcel Gil-Velasco). This bird stood among a group of arquata by its pale coloration. Note the classic orientalis breast pattern, the very pale tail and the characteristic contrast between the brown-fringed scapulars and the greyer wing. Note the sawtooth pattern typical of the juvenile tertials, contrasting with the replaced mantle feathers.
Oriental Curlews in Europe - what we know
Status and migration in the Middle East, Central Mediterranean and Spain
While not widely known within the birding community, the scientific literature describes orientalis as a regular migrant in the Middle East (Shirihai, 1997), and as a wintering species in Eastern and Southern Africa, including Western Africa (Delany et al., 2009). Upon reviewing pictures on eBird, it becomes evident that many of the birds observed in the eastern Mediterranean (e.g., Greece (bird 1, bird 2) and Turkey (bird 3, bird 4)) are likely orientalis of (presumably - see below for further discussion) Central Asian origin. Their presence may become rarer as one moves westward, but we have still come across several online sightings from Tunisia (bird 5), Morocco (bird 6), and Italy. This migration pattern is not surprising, as many Curlews in western Africa (e.g. Senegal and Western Sahara) are orientalis and, therefore, must cross the Mediterranean. In Spain, over the past three years, we have recorded a few orientalis-types and intergrades, primarily during migration, but also wintering in very small figures. So far, we have only found them in the Ebro Delta, where these Central Asian Curlews have proven to be quite regular during migration, and in Cantabria, where they are much rarer but still appear to be fairly regular. Although Cantabria and the Ebro Delta aren’t that distant in terms of kilometers, most waders crossing through Cantabria belong to the Atlantic flyway, whereas Ebro Delta is more influenced by the Black Sea/Mediterranean flyway.
Origin of the Curlews seen in the Mediterranean & W Africa
Although it is now clear that Central Asian orientalis is a scarce but regular migrant in the Iberian Peninsula, with some birds also overwintering, it is unclear to us where do these birds exactly come from. Many of the birds recorded in Spain were orientalis with some (but still obvious) arquata influence: slightly browner than classic orientalis from SE Asia, sometimes with some anchors in the flanks, and with shorter bills on average than those typical of orientalis. These birds may originate somewhere in Central Asia and are similar to those seen in some areas of Africa but also in India, where brownish birds with anchored flanks are not very rare (perhaps 20-30% of birds). There is already a case of a Eurasian Curlew tagged with a GPS in the wintering grounds in W France that turned out to breed the next summer east of the Urals in Central Asia (Frederic Jiguet, pers. comm.). The pictures taken when the bird was captured do not allow for a detailed assessment of the plumage features, but it does appear to be an arquata/orientalis intergrade, although leaning more towards the arquata side of the spectrum compared to the birds shown in this post and identified as Central Asian Curlews. Another Curlew marked with GPS at Santoña marshes, Spain, also oversummered in Russia, although it did not cross the Urals (Alejandro García Herrera pers. com.).
Interestingly, a couple of the birds seen in Spain looked like perfect eastern orientalis, likely indistinguishable from those wintering in SE Asia. Do these classic-looking orientalis originate from further East than the other, more typical, Central Asian birds?
Figure 15. Central Asian Curlew ssp. orientalis, adult male, Ebro Delta, Catalonia, Spain, April 2023 (Guillermo Rodríguez). A migrant adult seen in late April, this bird was also easy to pick by its very pale colour, in addition to the fine breast streaking and fine primary barring.
Figure 16. Central Asian Curlew ssp orientalis, adult, Ebro’s Delta, Catalonia, Spain, September 17th 2018 (Eric van der Werf). An obvious orientalis that surely would go unnoticed if seen in SE Asia. Note the late primary moult compared to arquata, and very pale fringes of the wing coverts.
Phenology & moult
European Curlews are very early migrants and breeders, with individuals wintering in the Iberian Peninsula returning to their breeding grounds by late February and arriving back in Iberia by late June. However, our observations of Central Asian Curlews in Spain suggest a much later breeding timing, as most migrants have been sighted between mid-April and mid-May. This phenology aligns with the pattern described in the literature for Eastern Europe. Although these observations are preliminary, they suggest a 1.5-2 month delay in the breeding timing of Central Asian orientalis compared to arquata. Figure 17 shows the number of arquata, orientalis and intergrades at the Ebro Delta from January-June 2023; the plot shows well that most arquata leave the wintering grounds in February, whilst migrant orientalis were mainly found in April. Hopefully, the emerging pattern depicted in Figure 17 will be confirmed over the next few years, with more locations across Western Europe monitored at this level of detail.
This difference in migration timing likely impacts on the phenology of moult as well. Curlews undergo primary moult in their wintering grounds following migration (if they migrate). In the Iberian Peninsula, Curlews moult their primaries during July and early August. In contrast, two of the orientalis individuals observed in Spain were still moulting their ninth and tenth primaries (p9 and p10) in mid-September and mid-October, respectively.
Figure 17. Distribution of individuals assigned to each type at Ebro Delta in winter - spring 2023 (Marcel Gil-Velasco). In Spain, most European Curlews leave in early/mid February (some young birds stay during the summer), whereas there is a slight peak of migration of orientalis-types and intergrades in late March and throughout April.
Discussion and conclusions
In this post, we have described the variability of the Eurasian Curlew across Eurasia, paying particular attention to the aspect of the birds wintering in Africa. We have shown that some of the orientalis (presumably) from Central Asia, which migrate to West Africa, can be observed in migration in Western Europe - they are regular in the Mediterranean and a bit scarcer along the Atlantic coast.
Identifying these Central Asian Curlews in Europe should not pose many problems, at least for the most classic birds. The general pale coloration is quite striking, especially when the bird is accompanied by the much browner arquata. As we have discussed, there are several supporting features, but the real clincher is the pattern of streaking on the breast and the lack of arrows on the flanks. However, there is a caveat to consider: some juvenile arquata present a similar pattern in summer and early autumn. Therefore, determining the bird's age is a crucial step in the identification process.
There are several aspects that require further understanding and study. Our field experience with arquata mainly comes from Spain, where the species is present mainly in winter. We suspect that many of the arquata seen in Spain are not of European origin but rather from further east - and thus perhaps our sample includes a mix of arquata and intergrades. A more critical review could help accurately address the variation within European breeding Curlews, so feedback from northern and eastern European birders monitoring their local populations is much welcome.
When considering the distribution of Curlew phenotypes in Africa, it appears clear that eastern orientalis-types are more common in South Africa, while western-orientalis become more prevalent as one moves north and west. The Western Sahara seems to mark the northwestern limit of regular wintering for orientalis. However, it is noteworthy that in Morocco, most Curlews appear intermediate between orientalis and arquata, likely originating in western Siberia, with classic arquata representing a minority. A similar pattern is observable across the Mediterranean, with a gradient where classic orientalis become rarer moving from the Eastern to the Western basin.
An intriguing question that still requires an answer is the origin and breeding range of these African wintering orientalis -i.e. how far east do the breed? As we have illustrated, some of them look identical to SE Asia winterers. We hope that in the near future, some of these orientalis will be equipped with GPS devices, which would definitely shed some light to this question.
Finally, we encourage birders to study and pay attention to Curlews, both in Europe and Africa. This will contribute to a better understanding of the variation and distribution of Asian Curlews. There is still much to understand, and perhaps even discover the wintering -and current breeding- areas of suschckini.
Figure 18. Central Asian Curlew ssp orientalis, male 2cy, May 2022, Bay of Santander, Spain (Guillermo Rodríguez). This bird was migrating along with a Whimbrel and briefly stopped to rest. A short-billed male, with partial moult restricted to the back and mantle (the entire wing is still juvenile). Note the typical pale plumage, with rather indistinct head lacking a dark cap, very fine streaking on breast and lack of arrows.
Figure 19. Central Asian Curlew ssp orientalis - intergade type, adult, Bay of Santander, Spain, January 2023 (Guillermo Rodríguez). An example of a bird seen in the Atlantic coast, this bird overwintered in Spain. Although still pale, large, long-billed and with only a couple of diffuse arrows on the flanks, it looks a bit browner than the previously shown Central Asian Curlews seen in the Mediterranean.
Figure 20. Central Asian Curlew ssp orientalis - intergrade type, 2cy+ (down left on the left picture, down bird on the right picture) with European Curlews, July 2021, Santoña marshes, Spain (Guillermo Rodríguez). Another example of a Central Asian bird showing some arquata influence, but still the bird stood up in a flock of arquata by its pale coloration and larger size.
Acknowledgements
We would like to thank all the photographers that kindly allowed us to post their pictures here: David Santamaría, Ramsés Pérez, Kiko Junco, Dave Bakewell, Savio Fonseca, Aseem Kothiala, Trevor Hardaker, Daniel López-Velasco, Eric van der Werf, Zbigniew Kajzer, Andrew Spencer and Peter Alfrey. Chris Gibbins was particularly helpful as he allowed us to study his extensive gallery of orientalis from Malaysia, allowing for a deeper understanding of the variability of some key plumage features. Frederic Jiguet and Alejandro García Herrera explained to us the movements of the curlews that they have equipped and tracked with GPS in France and Spain, respectively. We would also like to thank Sylvain Reyt for reviewing our draft and improving the text.
References
Corso et al., 2014. A review of the identification criteria and variability of the Slender-billed Curlew. British Birds, 339-370.
Delany et al. (2009). An Atlas of Wader populations in Africa and Western Eurasia. Wetlands International.
Peacock, F. (2016). Chamberlain’s Waders. The definitive guide to Southern Africa’s Shorebirds. Pavo Publishing.
Shirihai, H. (1995). The Birds of Israel. Academic Press.
Van Gils, J., P. Wiersma, G. M. Kirwan, and C. J. Sharpe (2020). Eurasian Curlew (Numenius arquata), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA.