Virée dans le delta, en images
Pas trop le temps pour écrire en ce moment (trop d’oiseaux à compter au Calao!) je voulais tout de même partager quelques clichés pris lors d’une nouvelle visite au Bas-Delta du fleuve Sénégal, au tout début du mois. En compagnie, bien sûr, du référent local et fin connaisseur de l’avifaune de la région – que dis-je, de la faune tout court – Frédéric Bacuez. D’abord les environs de Bango et les Trois-Marigots, puis une journée dans le parc national du Djoudj avec Vieux, Miguel et Rosa en plus dans la bande, puis pour terminer une matinée dans la réserve de faune du Ndiael. Pas loin (voire un peu plus) de 200 espèces observées pendant notre long weekend ornitho, tous les détails comme d’hab sur eBird.
Sans plus tarder, voici donc en ordre chronologique une petite série d’images:
Status & Distribution of Seebohm’s Wheatear in Senegal
This is the second part of a review of what we know about Seebohm’s Wheatear in Senegal, the first part covering its identification in autumn and winter. As already mentioned in that piece, this species has a pretty restricted range, breeding only in the Middle and High Atlas of Morocco and Algeria, generally above 1500 meters asl. Until fairly recently it was considered more of an altitudinal or short-range migrant, but it’s clear now that it’s actually a medium-range “total” migrant (i.e. all populations tend to migrate away from breeding grounds – not surprising given that much of it is covered in snow during winter!).
The non-breeding range of “Black-throated Wheatear” is given by the Handbook of the Birds of the World Alive as “West Africa (mainly SW Mauritania and Senegal to W Mali, occasionally in S Morocco)”. However, the HBW range map is rather incorrect: all regions of Senegal and Gambia and even Guinea-Bissau are included, although as far as I know the species has never been reported from the latter two countries. The same applies to Guinea and Burkina Faso which are also partly included in the range. Let’s hope that this will get corrected soon – the HBW species page of this newly recognised taxon (formerly considered a subspecies of Northern Wheatear) was only fairly recently published online, and is obviously work in progress.
The winter distribution in Shirhai & Svensson (2018) on the other hand seems more accurate, though perhaps a bit too conservative in that it includes only a very small part of western Mali. Judging by the data available on the Biodiversité Al-Maghrib portal, it’s clear that some birds winter may further to the north, much closer to the breeding grounds. Indeed, there are several observations from southern Morocco and from the Western Sahara from December-February, and it’s easy to imagine that it’s rather beneficial for these birds if they can avoid crossing the Sahara. There are also a few recent records from the Adrar region in Mauritania, e.g. this one and this one by Wim van Zwieten and friends seen at the end of December last year, suggesting that this area may also be part of the species’ winter range.
The Shirihai & Svensson map is most likely largely based on a paper on Seebohm’s Wheatear in West Africa by Förschler and colleagues (2008), which to date gives the most comprehensive overview of our knowledge of its wintering grounds in the Sahel, following field work they undertook in western Niger, Mali and Mauritania combined with a review of published data. They note that “although seebohmi was previously thought to be a resident or only a partial migrant by some authors, it is now considered a true migrant, with the majority of the population leaving Morocco and Algeria in winter. Browne (1982) found a major wintering area, roughly estimated to hold at least 50,000 individuals, in the eastern part of south-west Mauritania […].” They also refer to three more southern records from Djoudj NP (mentioned by Rodwell et al. 1996), and conclude that “the majority of this taxon’s population appears to winter immediately south of the Sahara, in the Sahel zone of southern Mauritania, northern Senegal and north-west Mali between 15–18°N and 09–16°W, although its wintering grounds may range even further east, including parts of central Mali.”
Away from its regular range, there are a few scattered records of Seebohm’s Wheatear in the Mediterranean and one from the Netherlands (April 2017), plus a couple of possible sightings from the UK: Italy (one in April 2014 in Sardinia), Gibraltar, Malta, Tunisia, and several times in the Libyan desert and even once from western Egypt. It’s also on the list of the Canary Islands, and apparently also reported from Cameroon, as per Arnoud B. van den Berg on DutchAvifauna,nl). So it’s definitely a species to have on one’s radar when encountering an unusual wheatear in western and southern Europe; I can imagine that one day a fine male will show up in spring in the Camargue, the Spanish coast or on the Balearic islands – or pretty much anywhere north of its range for that matter.
Status & Distribution in Senegal
In Senegal, in addition to the aforementioned Djoudj records, the species has been reported from the Richard-Toll, Dagana, Podor and Ndioum areas, and at least once from the lower Senegal valley, on 2.3.09 by Frédéric Bacuez, Ornithondar. Of course, Frédéric had already provided a comprehensive overview of the distribution of Seebohm’s Wheatear in Senegal, more precisely in this blog piece from 2016. The Morels mention several spring records (13 March – 14 April) in the middle Senegal valley as far upstream as Salde, plus one from early January 1981 near Richard-Toll seen by Alan Tye. They also report the presence on two occasions some 60 km south-east of Richard-Toll. But that’s about it: not an awful lot of records to go by! It’s quite possible that it may also be found at least occasionally in the Ndiael reserve, around lac de Guiers and into the Ferlo (e.g. Six Forages). These sites are not very often visited by birders or ornithologists, and the recent records that I came across are typically from Richard-Toll and the Podor areas, with the exception of a first-winter male at Saot (ENE of Touba), seen by J-F Blanc in January 2010. No records are known from the Grande Côte, though it’s not impossible of course that the species shows up here at least from time to time.
As can be seen from the map below, northern Senegal is on the southern edge of the species’ winter range, which may explain why most birds seen here appear to be first-winter birds. Adults, and in particularly males, may well winter further north including on the other side of the Sahara as mentioned earlier. Though it’s certainly not rare, the species seems to be nowhere common across its range in Senegal. When we toured the middle valley in January last year, we saw the species in small numbers (1-2 ind. per site) at three different locations: Bokhol, in a sparsely wooded dune depression east of Ndiayene Pendao, and at Gamadji Sare. Some sites such as the Bokhol “fores” appear to be pretty reliable, and a dedicated search would probably reveal other sites where they may be regular and maybe even locally common; in 1973 Seebohm’s Wheatear was said to be “the most common [wheatear] species in winter in the Podor region”, while Sauvage & Rodwell refer to a total of 18 ind. seen at three locations in February 1993 in the Podor atlas square. There may of course be annual variations, possibly depending on any cold spells in north-west Africa, but obviously more data are needed (as usual!).
The majority of sightings are made between December and early March, but this is when most birders visit the country and it’s likely that Seebohm’s is regularly present at least from (mid?) October and up to early April. In Nouakchott, it’s been seen as early as the end of September (see Rob Tovey’s eBird checklist with two pictures of a fresh autumn male), but when I last visited the Podor region in early October 2018 I did not see any birds on the sites that held several wintering individuals back in January, so it seemed that they had not arrived yet at that time.
In short, the main wintering area of Seebohm’s Wheatear lies in Mauritania, northern Senegal and NW Mali, on the edge of the Sahara and in the northern Sahel zone. It is a regular winter visitor to northern Senegal, being scarce locally fairly common along the middle Senegal Valley, from October/November to March or early April.
The main winter range in West Africa should look something like this, though it possibly extends a bit further south in Senegal and further east along the Mauritania-Mali border. And as mentioned already, some birds may winter in southern Morocco and in the adjacent Adrar region of Mauritania, as well as along the coast north of Nouakchott: the below map may well need to be adjusted as such – comment welcome, as usual.
While its habitat in summer essentially corresponds to Alpine meadows with rocks and stone structures, usually devoid of any trees, in winter the species may inhabit light Sudano-Sahelian woodland, at least along the Senegal valley. Elsewhere, particularly further north in Mauritania, it probably occurs mostly in more open habitat. The Bokhol forest just east of Dagana seems to be a reliable place to find Seebohm’s Wheatear: it is comprised of a mix of Acacia, Balanites aegyptiaca and other trees growing on sandy soil with little or no undergrowth. Indeed, most of the winter range of the species is heavily overgrazed anyway, and away from the floodplains there is generally very little vegetation cover… the picture below gives an impression of the the sad state of what remains of northern Senegal’s “forests” – a very liberal concept here at these latitudes.
We’ve also encountered the species on several occasions at Gamadji Sare, where part of the area is also made up of light woodland, not dissimilar to Bokhol, though less mature. Some birds here were seen in more open areas, including right by the bank of the Doué river where this picture was taken:
In much of its range, the species is cohabiting with Northern (ssp. oenanthe and probably also libanotica), ‘Greenland’ (leucorhoa) and Isabelline Wheatear, probably locally also with Black-eared and Desert Wheatears though the latter two species are typically very scarce in Senegal it seems. Heuglin’s Wheatear is also possible in winter in northern Senegal, but it’s much rarer and was added to the national list only recently, following a record in the Djoudj NP in January 2007 (and was found breeding even more recently in the Kédougou region).
A brief etymology¹ of Seebohm’s Wheatear
The HBW Alive lists this taxon as Black-throated Wheatear, another rather boring and unimaginative English name. I’ll stick to Seebohm’s. Alternatively, Atlas Wheatear would be a pretty good one as it nicely highlights the restricted breeding range of the species; this name is already in use in Spanish and German, and no doubt in other languages.
But actually, why Seebohm’s Wheatear? Tim Birkhead – author of (at least) two great books, The Wisdom of Birds and Bird Sense – wrote about Henry (or should it be Harry?) Seebohm, a 19th century British industrial and ornithologist, most famous for his fieldwork in Siberia. Which doesn’t really explain why our wheatear from the Atlas goes by his name… enter Charles Dixon, who formally described the taxon in 1882 based on a specimen from the Algerian Atlas. A contemporary of Seebohm, Dixon collaborated on Henry Seebohm’s British Birds opus, so I think it’s safe to assume that Dixon named his newly described chat in honour of his friend.
The term “wheatear” apparently comes from “white” and “arse”, referring to the prominent white rump found in most species.
¹ Etymology is the study of the origin of words and the way in which their meanings have changed throughout history. Applied to vernacular and scientific bird names, this comes down to retrieving the origins of these names.
Thanks once again to Frédéric Bacuez and Wim van Zwieten, and now also to Jérémy Calvo for making available some of their pictures from Mauritania and Morocco
Identification of Seebohm’s Wheatear in Senegal
Last winter, I had the chance to have a closer look at a species that is relatively little-known, particularly on its wintering grounds: Seebohm’s Wheatear, a former subspecies of Northern Wheatear that was fairly recently (though long overdue it seems) recognised as a full species by many authors, though surprisingly not yet by IOC. These neat little birds have a pretty restricted breeding range, only occurring in the Atlas mountains of Morocco and Algeria. A couple of years ago I had the chance of seeing these birds for the first time, more precisely in May on their breeding grounds at Oukaimeden, birding hotspot incontournable of the Moroccan High Atlas. As such it was particularly nice to meet up with them on their Sahelian wintering grounds a few months later, during our memorable trip up north in January 2018.
Wheatears can be tricky birds to identify, with several species often posing a bit of an ID challenge, and Seebohm’s is no exception. However, nothing much has been written about the identification of first-winters and adults in non-breeding plumage¹, and depictions in standard field guides may be misleading or even incorrect. In an effort to further our knowledge of the species, we thought it may be useful to summarise what we know based on our limited experience with Oenanthe seebohmi in the field here in Senegal, combined with a brief study of available pictures. Note though that by no means is what follows necessarily a comprehensive overview; additions and corrections are most welcome as usual.
A second blog post will focus on the status & distribution of the species.
Identification in winter
While straightforward to recognise in spring, Seebohm’s Wheatear on its Sahelian wintering grounds can be difficult to identify, mainly because they may superficially resemble Desert or Black-eared Wheatear, while young birds and some females may look like Northern Wheatear. We’ll start by reviewing field characters as found in the most relevant literature: mainly the excellent Robins and Chats (Clement & Rose 2015), Nils van Duivendijk’s Advanced Bird ID Guide (2010), and the recently published seminal reference guide by Shirihai & Svensson (Handbook of Western Palearctic Birds: Passerines, 2018). Let’s see how these can be applied to some of the pictures of presumed Seebohm’s taken in winter.
- Size & overall impression are very similar to Northern Wheatear, though it is slightly smaller than that species – something that’s not necessarily obvious in the field unless maybe in direct comparison to nominate Northern; it’s clear though that Seebohm’s definitely doesn’t look larger than Northern as is the case with ‘Greenland Wheatear’ (= ssp. leucorhoa) where the size difference is usually obvious in the field.
- Structure is typical of wheatears and does not appear to be very different from Northern either; the wing is supposedly slightly shorter, though this is not really obvious in the field, several of the pictures presented here actually show rather slender long-winged birds with an important primary projection, rarely giving a more compact appearance. On most pictures presented here we can however verify that the primary projection is slightly less than the length of exposed tertials (Shirihai & Svensson).
- The bill and tail are said to be “rather longer” than Northern, but these differences are again likely of little use in the field, and I’d imagine that there’s some overlap between species – more measurements on museum skins are likely needed to confirm this.
- In all plumages, the black terminal tail band is narrower than in Northern Wheatear (on outer tail feather, ca. one third of the length of the feather is black), though yet again this is not a very useful field character unless good pictures of the tail are obtained.
- Another key difference is that the underwing coverts are entirely black in males, while in females there are pale streaks on dark underwing coverts, unlike in Northern.
Adult and second-year males are generally straightforward to identify in autumn and winter, when they largely retain their distinctive head pattern, only to a limited degree obscured by pale fringes, combined with very pale underparts and “largely greyish or slighly sandy-grey” upperparts. As a result, adult males should be easy to pick out in autumn and winter, despite not showing the crisp black/grey/white plumage typical of spring males. Still, they remain very distinctive and are unlikely to be confused with any other species, such as this one from the end of March on wintering grounds in southern Mauritania, photographed by the late Robert Tovey (Birding for a lark blog):
The two birds below were photographed in Nouakchott by Rob Tovey, at the end of September and mid-October, respectively. Both are clearly males, and while not very grey, I believe both are 1st year birds (note moult limit on first bird). However, ageing of these birds “requires close inspection of moult and feather wear and pattern in wing” (Shirihai & Svensson) and is often not straightforward – more on this below. This bird on Afbid from January near Richard-Toll, photographed by Nik Borrow, clearly shows an adult-type male, with a largely grey crown, mantle and scapulars.
There appears to be some confusion about the plumage of adult females in the literature, with some authors only mentioning that adult females have a “(dark) grey mottled throat” (van Duivendijk), whereas Svensson in the Collins Bird Guide writes that “females and imm. are often inseparable from [Northern] Wheatear unless showing hint of mottled grey throat (rare though)”. Clement & Rose provide illustrations of an adult male and a dark-throated adult female, but don’t bother illustrating typical females, nor do they show any birds in autumn and winter. They do note that females are variable, ranging from closely resembling typical females of Northern Wheatear, to showing brown ear-coverts and having black or blackish-brown lores to chin and throat tipped with buff, grey or sandy colour – thus more resembling the males in head pattern. Not very clear!
Luckily, Shirihai & Svensson are more precise, stating that adult females are “almost identical to ad. f. (and young m.) libanotica Northern Wheatear, and contrary to previous descriptions nearly always lacks dark bib.” Black- or grey-throated females are thus considered rare. They go on to describe the upperparts as “largely pale grey (with limited sandy-brown suffusion) including on crown. Usually has duskier or almost blackish lores and ear-coverts; whitish supercilium often narrow and short, hardly extending to forehead […].”
Here’s a typical female in spring on the breeding grounds at Oukaimeden, and this picture on Afbid is from May at Ifrane. Adult females in autumn are said to be much as in spring but warmer.
The ageing criteria for first-winter birds, according to van Duivendijk, are as in Pied Wheatear [everyone knows these criteria by heart, right?!]: primary coverts with slightly frayed broad white fringes (ad autumn: often narrower and sharply bordered); primaries brown to brown-black often with pointed and worn tips; pale fringes to secondaries complete and cream-coloured; sometimes moult limit visible in greater coverts. There you go, just in case you’d forgotten. Ageing is thus largely based on moult limits, with first winter birds retaining juvenile primaries, primary-coverts and outer greater coverts, whereas in adults these are evenly fresh.
Back to Shirihai & Svensson, who state that first-winter males are “more female-like and rather feature-less, but still approaches fresh ad. m., having greyer upperparts and darker face with exposed black mottling especially on sides and lower throat; warmer below (Variation poorly known and requires more study)”, and that first-winter females have the “least contrasting plumage, with paler face pattern, and browner/duller ear-coverts.”
Let’s put the above to the test on some of our pictures from Senegal!
The following four photographs show three different birds from January; all are presumed to be first-winter males with varying levels of black extent on the face and throat. I initially assumed these to be adult males, but judging by the description of non-breeding males (by Shirihai & Svensson mainly) and compared to some of the pictures presented earlier on and those in Förschler et al., I now tend to label them as first-winter birds – mainly because of the overall sandy-coloured upperparts, mostly lacking grey tones. Again, keep in mind that ageing of these birds can be tricky and is not always possible! In the first bird, note the largely black throat and face appearing rather “smudged”, a fairly large white front merging into a clear whitish eyebrow extending well beyond the eye, and largely pale sand-coloured mantle and scapulars, the latter with a hint of light grey. The wings in the bird below appear relatively contrasted black and white, with extensive white fringes to the secondaries.
In this picture of the same bird, the greyish scapulars and some grey mottling on the back are more apparent:
This one taken earlier that same day in a different location shows a bird with less white on the chin and gives a very “cold” impression, though this is certainly exaggerated by the subdued early morning light. See also this picture of the same bird, as well as the second picture in this post (the one with spread out wings) which may well show the same bird, five weeks later in the same spot. Not sure about sex here – probably a male, but we probably can’t exclude a dark-throated female.
The same goes for this one from last December, taken by Wim van Zwieten near Podor. This bird also has fairly little black on the face but extensive pale fringes to greater and primary coverts as well as to secondaries, suggesting a first-winter male, though again not sure it can safely be sexed. These birds may be mistaken for Desert or Black-eared Wheatear (the black-throated form of which sometimes occurs in Senegal, though it’s probably rare), even by experienced birders.
The next bird gives a very pale impression, with uniform light sandy upperparts and a white lower breast, flanks, belly and vent. The upper breast are warmer tinged with a buffish wash extending down from the ear coverts, and so are the undertail coverts. The black or dark brown loral stripe is reminiscent of Isabelline Wheatear, but it has a narrow yet distinct supercilium both in front and behind the eye and has a different ‘jizz” and wing pattern than Isabelline. I’ve concluded that it’s a first-winter female, but as always would stand happy to be corrected. Either way, the very white underparts and pale upperparts stand out and should immediately point to Seebohm’s.
Of course, identifying a female or 1st winter bird in a vagrant context is something else. While not necessarily impossible, it will require a combination of characters as well as proper photographic documentation of underwing and tail pattern in particular. There have been at least two suspected birds in autumn in the UK but which could not be confirmed as definite Seebohm’s (read up more on these tricky birds here on Birding Frontiers). The first confirmed sighting for NW Europe was of a male in May 2017 in the Netherlands, a typical case of “overshooting” by North African or Mediterranean species during spring migration. Elsewhere in Europe, the species has been reported as a vagrant from Gibraltar, Italy, Malta, the Canary Islands.
Stay tuned for part II!
– Bram, with thanks to Frédéric, Simon, and to Wim for the use of his picture. And most importantly, a posthumous tribute to Robert Tovey who in a short few years made valuable contributions to our knowledge of birds in Mauritania, before unexpectedly passing away in September last year.
¹ Note (19.2.19): The only exception is actually a remarkable paper written by Mayaud in… 1951, in the French journal Alauda (19:88-96): Le plumage prénuptial d’Oenanthe oenanthe seebohmi (Dixon), in which the author provides a detailed description of birds in non-breeding plumage.
Yellow Wagtails at Technopole.
Sunday 06.11.2011, I went to Technopole. I was hoping to find that European Spoonbills, Godwits and Whimbrels had arrived from Europe – and preferably ringed, so I could report back. I didn’t encounter any of those. On top of all the usual suspects; 7 – 8 species of herons/egrets, the two species of comorants, Little Grebe, Osprey, Black Kite, Pied Crown, Pied Kingfisher, White-faced Whistling Ducks, Pied Kingfisher, Black-winged Stilts, Common Sandpipers and Wood Sandpipers, some gulls and terns I found a handful of Showelers enjoying the calmness of the lake.
However, the morning ended up as a hunt for warblers and different subspecies of Yellow Wagtails of different sub-species, and they were numerous.