C’est à trois que nous sommes partis à l’aube dimanche dernier, destination lacs Tanma, Mbaouane et Retba (Lac Rose). Il a fait chaud, très chaud, et après six heures sur le terrain nous étions bien cuits… mais comme toujours le déplacement en valait la peine: 103 espèces notées dont quelques “premières” pour la saison, trois coches pour Miguel et quelques dizaines pour Roel, et un rapace tout à fait inattendu (qui sera un ajout à ma liste “Sénégal”!).
A commencer par le lac Tanma, un peu plus accessible qu’il y a cinq semaines, le 4×4 de Miguel aidant. On commence par explorer la brousse en bordure de la plaine, histoire de voir si les passeraux européens sont déjà arrivés sur place (lors de notre dernière visite fin août, il y avait “juste” cette fameuse pie-grièche hybride et deux Hypolaïs polyglottes) et de se positionner du bon côté pour scruter le lac. En effet, il nous faut éviter le contre-jour qui empêche de bien voir les limis, canards et autres guifettes.
Les buissons donc: d’abord une Pie-grièche à tête rousse (bien pure celle-ci; Woodchat Shrike), puis deux Erémomèles à croupion jaune (Yellow-bellied Eremomela) – espèce désormais classique au lac Tanma – et effectivement, quelques migrateurs supplémentaires: Hypolaïs polyglotte, Fauvette grisette, Bergeronnette printanière. (Melodious Warbler, Common Whitethroat, Yellow Wagtail). Un Circaète Jean-le-Blanc immature est posé sur un baobab, alors que quelques Busards des roseaux, tout récemment arrivés d’Europe, évoluent au-dessus des rivages du lac (Short-toed Eagle, Marsh Harrier).
Pour le reste, on trouve les habituels résidents ou migrateurs afro-tropicaux: un Coucou didric chante au loin, plusieurs Rollier d’Abyssinie, un Agrobate podobé, un joli mâle de Beaumarquet melba, quelques Euplectes franciscains, Alectos à bec blanc en pagaille, etc. (Diedrik Cuckoo, Abyssinian Roller, Black Scrub-Robin, Green-winged Pytilia, Northern Red Bishop, White-billed Buffalo-Weaver).
Côté lac, il y a bien plus de monde qu’il y a cinq semaines: environ 435 Flamants roses (Greater Flamingo), une centaine de Sarcelles d’été (Garganey) et quelques dizaines de Canards souchets (Shoveler), et surtout: une nouvelle famille de Canards à bosse, une douzaine de canetons menés par Maman Bossue (Knob-billed Duck, aka Comb Duck). Et plus tard, neuf canetons avec deux adultes de Dendrocygne veuf (on dit alors des dendrocygnons? White-faced Whistling Duck). La reproduction du Canard à bosse n’est plus une surprise ici car on l’avait déjà confirmée en novembre 2013, puis suspectée l’an dernier, et lors de notre visite précédente une femelle est vue plusieurs fois en vol en train de crier. Celle du “canard siffleur” par contre est la première nidif que je constate ici; la date correspond tout à fait à ce qu’indiquent les Morel: “reproduction pendant les pluies de juilet à octobre (très peu de nids trouvés) et en Gambie entre septembre et novembre.” Impressionnant tout de même comment ces canards arrivent à nicher sur un plan d’eau temporaire (il y a deux mois à peine le lac etait à sec) avec très peu de végétation lacustre!
Et bien sûr pas mal de limicoles, bien que pour la plupart un peu loins: Chevaliers aboyeur, stagnatile, gambette, sylvain, guignette, culblanc (Greenshank, Redshank, Marsh, Wood, Common, Green Sandpiper) ; trois Gravelots pâtres et quelques Grands Gravelots, une poignée de Courlis corlieux et Barges à queue noire, plein d’Echasses et 5-6 Avocettes, quelques Combattants, Bécasseaux variables… (Kittlitz’s & Common Ringed Plover, Whimbrel, Black-tailed Godwit, Black-winged Stilt, Avocet, Ruff, Dunlin). Une Sterne caspienne se tient parmi les Sternes hansels et Goélands railleurs; cette fois on n’identifie qu’une seule Guifette leucoptère parmi les dizaines de noires, mais la plupart des laridés se tiennent sur l’autre rivage, un peu loin donc (Caspian & Gull-billed Tern, Slender-billed Gull, White-winged & Black Tern).
Pendant qu’on observe tout ce beau monde, un cri attire mon attention et je vois alors deux oiseaux passer derrière nous: des Coucous-geais (Great Spotted Cuckoo), apparemment un adulte et un jeune. Un peu plus tard un autre immature arrive en vol et traverse lui aussi le lac: oiseaux en migration active, ou nicheurs locaux? Mes amis genevois avaient vu un jeune nourri par des Choucadors à longue queue, le 12/11/16 au même endroit.
La surprise du jour viendra sous la forme d’un rapace passant haut dans le ciel que je tiens d’abord – à défaut d’autres options logiques – pour un Circaète brun… mais qui s’avère rapidement être un Aigle huppard (Long-crested Eagle)! Heureusement que Miguel était plus réveillé que moi. Arrivé du côteau de Pout, il cercle dans la zone tout en criant. Il y a bien une ancienne donnée non loin à Thiès (en décembre 1979!) sur eBird, mais actuellement cette espèce est restreinte, au Sénégal, au tiers méridional du pays. On s’attendra donc plutot à le voir à Toubacouta, en Casamance ou dans le Niokolo-Koba, mais certainement pas près de Dakar!
On rebrousse chemin pour se rendre du côté du lac Mbaouane et pour visiter un petit marais derrière le village de Beer, où l’on ajoute le Heron pourpré, un couple de Talèves d’Afrique, 2-3 Guêpiers perses, un Martinet des baobabs, des Hirondelles des mosquées, 3-4 Rousserolles des cannes et quelques autres à la liste (Purple Heron, African Swamphen, Blue-cheeked Bee-eater, Mottled Spinetail, Mosque Swallow, Greater Swamp Warbler). Plusieurs Balbuzards (Osprey) et quelques limicoles lointains fréquentent le lac lui-même, très peu profond comme le lac Tanma.
Il nous reste un peu de temps et un (petit) peu d’énergie, donc on fait encore un crochet par le lac Rose où je voulais parcourir la steppe au NE du lac, ces pelouses halophiles qui avaient produit quelques surprises l’hiver dernier. D’abord quatre superbes Courvites de Temminck (Temminck’s Courser) au bord de la piste, puis plus tard encore un qui passe en vol, et encore trois individus levés alors que nous étions en train de rechercher l’Alouette chanteuse (Singing Bush Lark). Visiblement la zone est un bon “spot” pour ces deux oiseaux qui peuvent être difficiles à trouver ailleurs dans la région. Une voire deux Alouettes seront vues, dans la même zone que l’hiver dernier (et en plein chant de parade, tournant haut dans le ciel telle une Alouette des champs).
Sinon assez peu d’oiseaux sont vus dans ce secteur, mais on entend deux Outardes de Savile (Savile’s Bustard) chanter au loin dans les dunes – une première pour moi si près de Dakar. Un petit groupe de limicoles passant en vol est composé de six Corlieux et quatre Barges rousses, deux espèces que je vois de temps en temps migrer ensemble devant Ngor (Whimbrel & Bar-tailed Godwit). Un Héron mélanocephale (Black-headed Heron) passe lui aussi en vol: une fois de plus, cette espèce semble bien régulière dans les Niayes, ce qui ne ressort pas sur la carte de répartition du Borrow & Demey. Les rives nord du lac sont fréquentées par des dizaines de Bécasseaux minutes et quelques sanderlings, avec en prime deux Pluviers argentés, mais point de laridés (Little Stint, Sanderling, Grey Plover).
Yesterday, Gabriel and I paid a visit to Lac Tanma – our first of the season and of what will hopefully be a series of regular visits there.
We’d barely arrived near the lake, after a couple of failed attempts to find a driveable track towards the lake (too muddy!), when we noticed a shrike sitting on top of a thorny bush. The overall appearance was that of a fairly large, greyish shrike, but quite a few things were just wrong for a Southern Grey Shrike (which given the time of the year would have been surprising to see here, as it typically shows up between December and February/March).
Suspecting a hybrid, we took a number of pictures before the bird flew off, which allowed us to compare with photographs and descriptions of known hybrids. I vaguely remembered that a few years back (it turns out this was in 2010) a similar hybrid had been reported from the French Jura, and that there was a drawing of another French bird in the excellent Shrikes – A Guide to the Shrikes of the World (Lefranc & Worfolk 1997).
This is what our bird looked like:
In typical shrike fashion, this bird had a distinctive black “Zorro mask” with an otherwise grey head and largely grey back (faintly mottled brown); white scapulars; black wings with a fairly large, elongated off-white patch at the base of the primaries; entirely pale salmon-pink underparts (from the throat all the way to the vent); and a white rump contrasting with its long black tail. In the field we noted some narrow pale borders to tertials, but these are not well visible in the pictures.
While a lot of hybrids between two bird species typically resemble both parents in one way or another, showing intermediate characteristics, this is not the case here. Our bird superficially looks like a Southern Grey Shrike, but clearly isn’t one: the buffish underparts especially, but also the seemingly all-dark tail (no white outer rectrices) and the lack of distinct white markings on the tertials and secondaries. Moreover, the structure and size – even though our bird seemed quite large – were not right for Southern Grey which is larger and more powerful (cf. a couple of pictures taken last winter in Palmarin). The same pretty much applies to Lesser Grey Shrike, which in addition has a black mask that extends to the forehead and lacks the white scapulars.
So who are the parents? Based on comparisons with pictures of hybrid shrikes and with the drawing and description in Lefranc & Worfolk, these types of birds are considered to be hybrid Woodchat x Red-backed Shrikes. The former is the most common Palearctic shrike species in Senegal, while the latter doesn’t usually occur in West Africa. The black mask, grey head, and “pinkish-white” underparts are typical of Red-backed, while the white scapulars, rump and wing patch are indicative of Woodchat. The grey back is a bit odd but has also been observed on other presumed hybrids with these two species as parents, and the faint brownish mottling hints at a hybrid origin. Another option would be a hybrid Woodchat x Lesser Grey Shrike, though there’s apparently only one such suspected bird that has been observed, in Hungary in 1979 (Handbook of Avian Hybrids of the World, McCarthy 2006). Much less likely, and one would expect at the minimum a black front on such hybrids¹.
Now compare our bird with the painting of a hybrid noted in France in 1995, fig. 26g:
Comments on the identification of this bird are more than welcome of course!
As far as I know, this is the first record of such a hybrid in (West) Africa; all other published data are from birds on migration or on breeding grounds in Europe. In recent years there’s been one such bird in Switzerland (April 2014), one in the French Lot department (May 2014), while hybrid males have bred (successfully!) with female Red-backed Shrikes in 2005 in South-East Belgium (short note available in PDF here), and in 2010 and 2011 in France. Pictures of the 2010 Jura bird can be found e.g. here and here. At least 12 mixed pairs have been found in France, but it seems that nothing is known on the whereabouts of these birds outside the breeding season: do they migrate to East Africa just like Red-backed Shrikes, or can they be found anywhere in Woodchat Shrike’s wintering grounds? Lefranc & Worfolk describe the latter as “a vast belt running across the African continent just south of the Sahara and largely north of the huge forest areas”. Our observation would suggest that they can show up anywhere in that area.
Other than our peculiar shrike, we had a pretty good morning out birding, with close to 100 species seen. Lac Tanma didn’t hold an awful lot of waders (a few hundred only, mostly Black-winged Stilts) but we did confirm breeding once again of Kittlitz’s Plover, while a female Knob-billed Duck also showed signs of breeding as it was seen flying around several times (and sometimes calling, which is associated with courtship behaviour). There were about 250 Greater Flamingos (and ca. 220 more at lac Mbaouane), several Gull-billed, Caspian, and White-winged Terns, but very few herons. A surprise find was that of three Spotted Thick-knees on the edge of the lake’s floodplain, quite close to the main road. Several Diederik, African and Jacobin Cuckoos were seen or heard, as were a few Broad-billed Rollers (another wet season visitor) and a single Purple (=Rufous-crowned) Roller. As usual, Mosque Swallows were hawking insects above the lake shore and the baobab forest; the latter also had a singing Hoopoe and several Woodland and Grey-headed Kingfishers. Besides the shrike, the only European songbirds that we spotted were two Melodious Warblers.
A Purple Heron at a small marsh near the village of Beer was my first of the season; we also found African Swamp-hen, Red-eyed Dove, and African Thrush here. Lac Mbaouane was visited only briefly and we just scanned the NW side of the lake, which had a few dozen Common Ringed Plovers and some Little Stints, while a few Blue-cheeked Bee-eaters were flying over and a Red-necked Falcon dashed over the lake as it was hunting.
(Regular readers will wonder what’s happening at Technopole. Well, I paid my first visit in three (!) weeks this morning, together with Theo. Water levels are rising with every shower, so conditions are getting less ideal for waders. Still a few hundred Ruffs, some Curlew Sandpipers, ca. 50 Sanderling and a few Little Stints, a handful of Black-tailed and a single Bar-tailed Godwit, Marsh, Green, Wood & Common Sandpipers, Greenshank, Redshank, a few migrating Whimbrels, etc. Also Shikra, a Hoopoe, and again a Broad-billed Roller to name but the most interesting records. The most unusual record this past week was actually one from Almadies: a Hadada Ibis flying over our house one morning! More on that one later, if I get the chance to write something up.)
¹ N. Lefranc mentioned that a mixed pair senator x minor was found in France last year. And that so far, no hybrid or mixed pairs senator x meridionalis have been recorded.
In recent weeks I’ve had the chance to pay a few visits to several of the Niayes wetlands, first at Mboro (twice, on Nov. 16 and 18), then Lac Tanma and the wetlands between Mbayakh and Kayar (Dec. 11), and finally near Lac Rose (Dec. 18). Lake Tanma has already featured several times in these pages, and Technopole is of course one of the most prominent and often visited sites, but little has been written about some of the other wetlands along the “Grande Côte”.
Since they are considered an “IBA” (Important Bird Area) by BirdLife International, there’s a pretty good description of the area on BirdLife’s website, so rather than coming up with my own overview I’ll quote from those pages. The Niayes are “a string of permanent freshwater lakes and additional temporarily wet depressions (niayes) lying along a line running north-east from the outskirts of Dakar to around 60 km south-west of St Louis. The lakes lie behind the ridge of coastal sandy dunes, in shallow depressions at 1–4 m above sea-level, over a distance of c.150 km. They are replenished both by rainfall and from the underlying water-table, which lies close to the surface. The wetlands cover 40 km² at low water [i.e. during the dry season]; at high water, all the lakes can increase their surface area five-fold.”
As is the case with many other IBAs in Senegal, the Niayes face quite a number of threats and have no legal protected status: “The whole site is threatened by human encroachment and various forms of development, particularly those niayes such as Hann Mariste and Pikine-Guédiawaye [= Technopole!] that are within or close to Dakar and to the main road leading east and north out of the capital. One of the main threats is from drainage and land reclamation for building, which is proceeding very fast. Over-abstraction of water and various forms of pollution threaten the hydrology and water quality of the underlying water-table. In addition to their immediate conservation value, the niayes represent a huge educational resource (large numbers of easily visible, interesting birds, very close to dense urban centres), which will also be lost if the site is further degraded.”
The two images below, taken in opposite directions just a few minutes apart, nicely illustrate the effect the presence of water has on the landscape – and by extension on its wildlife: dry dunes with sparse thorny shrubs on one side, lush vegetation and cultivated fields on the other.
The small lake just south of Mboro (near the ruins of Hotel du Lac, a couple of hundred meters off the main Mbayakh-Mboro road) is one of several wetlands around this busy little town, and a perfect spot for a quick stop while traveling from Dakar to northern Senegal (or for the return journey!). While we only scratched the surface, the lake can obviously be a very rewarding birding site both for local and migrant species. There are impressive densities of African Swamphen, African Jacana, Common Moorhen and Squacco Heron, and several Black-headed Herons have been seen here on every visit. In November, a handful of Pintails and White-faced Whistling-Ducks were here, as were a few waders: Black-winged Stilt, Wattled and Spur-winged Lapwings, Wood Sandpiper, Common Redshank, Common Snipe. Several Little Grebes were around, including at least one breeding pair. During a quick stop on 4/1/17, in addition to most of the species already listed there were 8 Shovelers, a Garganey and ca. 18 Ruff here.
The area is obviously quite good for raptors, with African Hobby (a presumed pair), Marsh Harrier, and Short-toed Eagle seen on both visits in November, as well as Black-winged Kite on Nov. 18th. While checking the sky for raptors, Mottled Spinetail could easily be seen among the Little Swifts, while the bushes on the slope above the lake held African species such as Purple Roller, Northern Anteater Chat, Piapiac, Yellow-billed Shrike, and Fork-tailed Drongo.
Also here was a Gambian Sun Squirrel Heliosciurus gambianus which was spotted by my friends shortly after I’d left the site. Unlike the Striped Ground Squirrel, it’s not an easy species to see in these parts of the country.
At “lake” Mbaouane (or Mbawan as it seems to be spelled locally) there are extensive moist grasslands as seen on the first picture in this post, and there’s a sort of oasis running from the town of Mbayakh to the lake. I’ve been wanting to visit for quite some time but it’s only recently that I decided to head out there. That morning I first went to Lake Tanma, but this has completely dried up by now, with only the two small ponds on either side of the bridge now holding some water. As a result, all the ducks, waders, gulls and terns have left the site, with only a lone Osprey to be seen where less than a month before there were thousands of birds. We’ll now need to wait until August next year for the lake to fill up again. (Birding was still good though: a Short-toed Eagle, a pair of Temminck’s Coursers, a juvenile Green-winged Pytillia, 2-3 Purple Rollers, plus the usual suspects and a young African Wolf all made up for the lack of waterbirds).
One of the first birds I saw after getting out of the car near Mbaouane was a Blue-bellied Roller, a species that I hadn’t seen so far in the Dakar area (my only record up to now was in Casamance). It’s likely a rare resident or maybe a wet season visitor up to this latitude and surely it’s at the edge of its range here. Morel & Morel mention that they can be seen up to around Thies, which is just a bit further inland. It turned out that there were two birds here, presumably a pair (in the picture below, one can see that the bird on the left has longer tail streamers; I assume this to be the male).
Another interesting record here was that of a Quailfinch, which in typical fashion flew over hesitantly while uttering its distinctive call. This species is well known from the Saloum delta and is also present in the lower Senegal delta, albeit in lower densities it seems, but is not regularly recorded from the Niayes as far as I know (which admittedly is most likely a reflection of the absence of birders in this part of the country!). Regardless, the fact that this is largely a resident species and that December corresponds to the breeding season in Senegambia, one can assume that the species occurs routinely in the area.
Some of the other birds seen here were Purple and Black-headed Herons, while Mottled Spinetail, Red-chested and Mosque Swallows were flying overhead.
Also known as Lac Retba, this is a bit of an unusual Niayes lake in the sense that it is a permanent salt water body, well known for its salt industry. As such, bird life is quite different from the other wetlands in the region: besides a few gulls, Greater Flamingos and a few waders, few birds are present on the lake itself. During my recent visit to the place, there were no flamingos – only a single Audouin’s Gull, the usual Ospreys (probably 15-20 in total), but a decent gathering of waders was found towards the eastern edge of the lake: Common Ringed and Kentish Plovers, Grey Plover, Whimbrel, Little Stint, Sanderling, and Turnstone. Also here was a White Wagtail, while the plains to the north-east of the lake held Singing Bushlark, Chestnut-backed Sparrowlarks, Tawny Pipit, Yellow Wagtails, etc.
I then made my way to the edge of the seasonal lakes (now all dried up) and the dunes even further towards Kayar, where a good mix of local species was to be found: Black-headed Heron, Double-spurred Francolin, Vieillot’s Barbet, Grey Woodpecker, Brown Babbler, Splendid Sunbird, White-rumped and – more surprisingly – Yellow-fronted Canary to name but a few. Common Whitethroat was the only northern migrant here.
On the way back, a quick scan of a grassy field produced the surprise of the day under the form of three Buff-breasted Sandpipers loosely associating with a flock of Kittlitz’s Plovers – see my earlier post on this exceptional record, plus the bonus picture below.
Juvenile plain-backed pipit
Sunday morning was spent at Lac Tanma, just east of the fishing town of Kayar, with Bram Piot. A 2.5km width of sand dunes separates the lake from the sea, but numerous shells in the soil indicate that this must once have been been an inlet of the sea, isolated from the Atlantic at some point by the spread of the dunes. The water tastes a bit salty, but there are water lilies on the fringes of the part of the lake south of the Bayakh-Mboro road, which I associate perhaps erroneously with fresh water.
Lac Tanma: east of Kayar either side of the Bayakh-Mboro Road
This is a temporary, rain-fed lake, dry last winter by February. As with other such lakes to the north and south of Dakar that I have recently visited, it is bursting with water after this year’s heavy rains (there were a few drops today) and there is little habitat for waders. Whereas on 12 November 2012 a few hundred each of ruff and little stint were on the lake margins and hundreds of greater flamingos feeding in the centre, today the numbers were respectively less than 10, nil though still with a few hundred greater flamingos, but clustered at the far edge and inactive. A few hundred Palearctic ducks,, a mix of northern shoveler and garganey, had arrived, but the exciting waterfowl find was a female knob-billed goose with six flightless young. It has surely been overlooked, but this seems to be the first documented breeding for Senegal¹.
Otherwise the dominant waterbirds were feeding black terns and less active gull-billed terns. Perhaps 10 ospreys circled or loafed on the banks and there was a reasonable mix of other raptors; 3-4 marsh harriers, 2 peregrines (one taking a black tern in flight), a female/juvenile montagu’s harrier, african hobby and adult short-toed eagle.
Paleartic passerines were also quite varied. The lake is fringed by low scrub, especially tamarisk, and a few small fields with hedges. This habitat was full of subalpine wablers, with smaller numbers of melodious warbler and one or two willow warbler, common whitethroat, northern wheatear, woodchat shrike, tree pipit and turtle dove. A few yellow wagtails and sedge warblers were around the lake edge and a pallid swift flew over.
Of african resident passerines, a male sahel paradise whydah and several northern red bishops were still in full plumage, whilst two male pin-tailed whydahs had moulted.
Almost at the end of the visit, the plain-backed pipit caused some initial confusion, as the immature plumage with white-ish edges to the feathers on the back gave it less of a “plain back” than its name suggests. This is not a rare species and not assumed to be localised in Senegal, but not one seen much here.
Immature plain-backed pipit
Finally, two photos of an African savanna monitor lizard (perhaps less often seen by birders than the Nile monitor lizard well known from Dakar’s Technopole and Djoudj), that took fright up a bush.
¹ Note by Bram (Dec. 2016): B. Tréca and C. Rouchouse report several breeding records from Lac de Guiers, in Malimbus vol. 11 (1990): Note sur la reproduction du Canard casqué (Sakridiornis melanotos) dans le nord du Sénégal.