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).
(in case you missed the first part, you may want to read this post first)
Thanks to the important research and conservation efforts targeting Audouin’s Gull, a substantial proportion of the population carry colour-rings, to the extent that in any given group one encounters here in Senegal (and elsewhere of course), there are bound to be some ringed birds, usually up to around 15% of all birds. As far as I know this is far more than for any other species that spends the winter here in Senegal; only Black-tailed Godwit comes close (often 5-10%) and maybe Osprey. For instance at Palmarin last month I managed to read 32 rings out of a total of ca. 400 birds, out of which some 200-250 were either close enough to read rings, or were standing (rather than sitting, in which case rings aren’t visible). That’s roughly 13 to 16% of individuals carrying coded rings!
The first mention that I found of a colour-ring recovery is from Delaporte & Dubois (1990) who on 26/1/88 at Saint-Louis observed a bird ringed as a chick in spring 1981 on the Chafarinas islands. Del Nevo and colleagues also noted that many of the birds they counted were ringed, e.g. on 30/9/92, no less than 24 (14%) of 167 birds were ringed: 18 had a darvic [=plastic ring with alphanumerical code] and six had a metal ring only. In 1994 in Palmarin, a Scandinavian team were able to read 16 colour-ringed birds from Spain (out of at least 456; Bengtsson 1994), while Sauvage & Rodwell mention nine colour-ringed birds originating from Spain, in Saint-Louis. The Dutch 1997 expedition managed to read nine rings, out of the 858 gulls that they counted, noting that “these birds presumably all originated from the Ebro Delta, Spain” (and certainly not from the Canary Islands as stated by Triplet 2014! The species doesn’t even breed there… not sure where this error originated).
The rings (or “bands” for our American friends) are either white with a black inscription (3 or 4 alphanumerical characters), or blue with a white 4 character code, and can often be read with a telescope or a good camera. White rings are used in Spain (starting with letters A, B, C or a number) and Italy (I or K), while blue rings are in use in Portugal (with first character P). French birds have a combination starting with F (since 2013; prior to this Italian rings were used); Moroccan ones with M. The images below show an Italian and two Spanish birds (“BDCT” appears twice, photographed in Aug. 2016 and Sept. 2017).
Origin of wintering birds in Senegal
I now have close to 50 ring “recoveries” related to 44 birds, most of which are from Palmarin (39), the others being from Technopole. Adding other sightings in Senegal of these same birds (mostly by Ngoné Diop), we have a total of 103 recoveries.
Here’s a quick summary of their origin:
- As can be expected, the vast majority are from Spain, particularly from the Ebro delta which accounts for about a third of all birds for which I know the origin (15 out of 44). Six are from Valencia (PN de l’Albufera, Salinas de Torrevieja), three from Tarragona (Salinas de Sant Antoni), three from the tiny Isla de Alboran between Morocco and Spain, and two each from the Balearic islands (Mallorca and Menorca), from Murcia (Parque Regional San Pedro del Pinatar and Isla Grosa), the Laguna de la Mata in Alicante, and the Chafarinas islands.
- Six birds are from Portugal, but I’m still awaiting information for full details of the five most recent birds (all from Palamarin early September); thanks to Ngoné I know that at least four birds (and likely all six) originate from the colony on Ilha da Barreta (the southernmost tip of the country, near Faro).
- Earlier this month I found my first Italian gulls at Palmarin, three adults (ICTD, ILBJ and K7T). I have not yet received details from the ringing scheme, other than that K7T was ringed in 1998 – so far my oldest bird! Ngoné kindly provided me with info for ICTD and ILBJ as these were already known to her, which allowed me to include Cagliari (Sardinia) and Isola del Giglio on the map below; I will add further info here when it becomes available [Olly Fox kindly informed me that K7T was seen at the Kartong Bird Observatory in The Gambia in November 2016; it was born on Isola dei Cavoli off southern Sardinia].
At least one Corsican bird has been found in The Gambia (Recorbet et al. 2011) and Ngoné has recorded a few French birds in Palmarin. One can assume that some Moroccan birds may also winter in Senegal, and maybe Algerian and Tunisian birds as well. Not quite sure where the Eastern Mediterranean populations spend the winter, but I read that at least some remain around their breeding grounds.
Here’s an example of the “life history” of one of our oldest birds¹, 45P from Spain, pictured in the header image of this post. It was ringed as a chick in 1999 on the Chafarinas islands, and was seen in The Gambia during the 2004/05, 2006/07, 2007/08 and 2011/12 winters, then in October 2014, October 2015, and September 2017 it was spotted in Palmarin (plus a few times on its native island, in April-June). Could it be that many Audouin’s Gulls spend the initial 4-5 months of the non-breeding cycle in Senegal, then move to The Gambia for the remaining 2-3 months of the northern winter?
The age composition of our wintering Audouin’s Gulls varies considerably between areas and apparently also through the season. This was first documented by del Nevo et al.: “Adult birds dominated both surveys and proportionately more adults than first year birds were present during September 1992 than in February 1991. Our observations are consistent with the view that adult Audouin’s Gulls tend to arrive in Senegambia before first year birds; the ratios of first year to adult were 0.1:1 in September and 0.54:1 during February.” Delaporte & Dubois reported an overall proportion of 15% of immatures. These ratios have likely changed now, at least in terms of the seasonality now that some immatures can spend their first summer in the region. Ngoné and colleagues reported estimates of 278 adults and 167 immatures (= 37,5%) in Palmarin for the 2013-2015 period. They also found that adults, 3rd and 2nd winter birds arrive earlier than 1st winter birds, a difference which “is probably due to differences in experience among age classes.”
The differences in “immature-to-adult” ratio between Palmarin and Technopole are striking, and I wish I knew what causes this. Immatures are by far outnumbering adults at Technopole, as opposed to the high proportion (70-80%?) of adults further south, particularly in the Saloum delta. Interestingly, this may not have always been the case: Oro & Martinez mention that juveniles winter further south than older 2-3y gulls, in the Senegambia region: “After the breeding season, 2-3y and older gulls were recovered mainly at the E and S Iberian Peninsula coasts. During the winter season these gulls moved southwards, especially to the Atlantic coast of Morocco. Juveniles behaved differently, moving further south than 2-3y and 4y or older gulls, reaching the Senegambia coast in high percentages (81,8%).” Is it possible that this was at a time when a new generation of young birds was in process of establishing an overwintering tradition in Senegal and The Gambia, returning in subsequent winters? That would explain why there are currently more adults than juveniles.
Two ringed individuals show how birds wintering in Senegal will typically spend their first year around the Cap-Vert peninsula, before moving on to the Saloum delta once they are older: BNH5 was ringed as a chick in June 2011 in the Ebro delta, after which it was seen at Technopole in July 2012, but during its third winter in Dec. 2013 (N. Diop), and again in Sept. 2017, it was in the Palmarin lagoons. AWNV, born in 2010 in Mallorca, was first at Technopole while in its second summer (July 2012), while in 2015 and 2016 it was in Palmarin. Some birds already move to Palmarin during their 2nd winter (e.g. BWU9), or even 1st winter (BPZ9, seen by Simon in January 2013, then by Ngoné in December of the same year and in Oct. 2015, and last month I saw it again. Talk about site fidelity!
All ringed birds recovered from Technopole were at most two years old, though of course there are some older birds and every now and then a full adult will show up. BYPB is a typical first-year bird, seen here in March 2017.
Among the ringed birds that I have found there are quite a few old individuals, the oldest being nearly 20 years old. Indeed, Audouin’s Gull is a long-lived species with a high adult survival rate (and relatively low fertility). The oldest bird I have is from Italy, at 19 years, while from Spain there’s 45P and 66P, both born in 1999; Ngoné had already seen both in 2014 and 2015 in Palmarin; 45P and was again at Palmarin earlier this month, while I saw 66P there last year at the end of August last year.
The little chart below shows the distribution by age at the time of the last sighting, for 43 birds for which I have the ringing year (birds are typically ringed as chicks, usually in June, so we know their precise age). One can clearly see the predominance of birds in their first year (= juveniles and 1st winter), though this is hardly surprising given that these all correspond to Technopole recoveries. I don’t know how to explain the near-absence of two- and three-year old birds.
Ngoné’s systematic visits to Palmarin have resulted in some 500 ring readings, which of course allow for a more thorough analysis than my anecdotal observations. Through modeling the team has estimated annual survival rates and the size of the wintering population in Palmarin, which are summarised in this informative poster presented at PAOC just about a year ago. There are of course also a few interesting individual stories in the lot, such as two Spanish birds that were ringed on the 15th and the 19th of June 2015 respectively, and that were seen within a few weeks after they left their colony (25/8/15 and 15/9/15).
To be continued…
Many thanks to Ngoné Diop for her input!
¹ The oldest bird we have is “FDA”, ringed as a chick in June 1988 (!) at Islas Columbretes, Castellon, and seen in 2015 and 2017 in Palmarin, and in Dec. 2017 in The Gambia.
When I started birding nearly 30 years ago, Audouin’s Gull was one of those near-mythical birds, endemic to the Mediterranean and listed as an Endangered species on the IUCN Red List. Plus, it’s a real pretty gull, much more attractive than the standard “large white-headed gull”. Fortunately, this highly coastal species has seen substantial increases in its breeding population and has (re)conquered new localities, mostly during the nineties.
It is now found in Portugal (where it didn’t used to breed 30 years ago), Spain (where the bulk of the population breeds), France (Corsica), Morocco, Algeria, Tunisia, Italy, Croatia, Greece, Cyprus, and Turkey. The largest colonies are in the Ebro delta (14,177 in 2007) and the Chafarinas islands off NW Morocco (2,700 pairs in 1997). The Ebro colonies now represent about two thirds of the global population, so it is particularly of note that the species wasn’t even breeding there in 1980: Audouin’s Gull established itself in 1981 when 36 pairs bred, with as many as 4,300 in 1990, +10,000 pairs in 1993… and now certainly more than 15,000 (I didn’t immediately find any recent figures).
The species’ global population is now thought to number 63,900-66,900 individuals, with 21,300-22,300 breeding pairs: to write that this is “a significant increase from an estimated population of 1,000 pairs in 1975” certainly is an understatement… This remarkable feat is thought to be a result of the increased availability of effectively protected areas during the 1980s and of discarded fish from trawlers, particularly around the Ebro delta. Although it may still be vulnerable due to its small number of colonies, it was downlisted to “Least Concern” during the 2015 revision of the Red List, previously being considered Near Threatened (2004), “Lower Risk/conservation dependent” (1994), and Threatened (1988) (IUCN). Quite a conservation success story.
Following a good harvest of ring readings a few weeks ago in the Saloum delta, I wanted to find out a bit more about its history, trends, abundance and distribution in Senegal – and decided to turn it into a blog post here. This wasn’t too difficult given that a ton of research has been done on Audouin’s Gull, resulting in decent knowledge on its population dynamics and structure, distribution, breeding ecology, dispersal, feeding and migratory strategies, etc. The main challenge was to identify the most relevant resources and to distill everything into something relatively concise. And for once there’s even fairly abundant literature on the species in its wintering grounds here in West Africa.
First, let’s have a look at historical records of Audouin’s Gull in Senegal, and see if we can reconstruct the trends for the country.
The ’60s and ’70s – the first records for Senegal
We automatically turn to our rapidly deteriorating copy of Morel & Morel (1994), who only list a handful of records – essentially, the first four records for the country:
An immature collected at Saint-Louis, 11/5/61 and an adult seen on Gorée island (Dakar) on 13/3/64; one photographed at “the entry of the Sine-Saloum” [wherever that may be! I assume near the Saloum river mouth?] on 1/2/75, and one record near Dakar at the end of December 1981.
Dupuy (1984) adds the observation of an adult in the north of the Saloum delta on 13/12/80 but this record was either overlooked, or not retained by M&M. Interestingly, De Smet & Van Gompel (1979) did not encounter the species even though they covered large chunks of the coast between lac Tanma and the western Saloum delta, as well as the Senegal river delta, during the 1978/79 winter. This seems to confirm that Audouin’s Gull at the time was still a rare or very scarce visitor here – something which was about to change very soon.
The ’80s and ’90s – establishment of a wintering tradition
Moving on, Sauvage & Rodwell (1998) consider Audouin’s Gull to be “frequent at PNLB (Langue de Barbarie NP) and Saint-Louis, Jan.-Apr. with max. 17 birds, Jan. 1994, nine ringed in Spain. Up to 10 were wintering around Saint-Louis, 1990-91.” It is “frequent to common Dakar off Pointe des Almadies and Toubab Dialao, Jan.-Mar., max. 104 (four ads.), Toubab Dialao, Jan. 1992. Frequent to abundant Saloum delta. Max. 321 wintering.” The latter figure, obtained in 1985 (Baillon 1989) is significant as it is the first mention of a substantial number of birds in Senegal, and can likely be linked to the “explosion” of the Ebro delta colony. In Jan.-Feb. 1988, Delaporte & Dubois counted gulls all along the Senegambian coast, from the Mauritanian border to Casamance, and counted 81 Audouin’s Gulls (6 near Saint-Louis, 3 along the Petite Cote, 72 around Palmarin) though they estimate a total of 130 birds. They also mention the presence of 185 in the northern Saloum (probably Palmarin/Joal-Fadiout) on 6/12/88. Del Nevo et al. (1994) conducted counts in February 1991 and in September-October 1992, noting a total of 459 birds in Senegal and 72 in Gambia (1991), and 276 in Senegal the following year, mainly at Sangomar and Joal-Fadiouth.
A few eBird records from the early nineties provide some more context for that decade, in particular the count of no less than 470 birds at the Somone lagoon on 28/2/91, with two at Mbodiene (south of Mbour) a couple of days earlier, and 12 at Plage de Hann (Dakar) on 18/2/91 (O. Benoist). Bengtsson (1995) reports a minimum of 456 near Palmarin in Nov.-Dec. 1994. Based on these records, it looks like the species became a regular winter visitor to Senegal in the early to mid ’80s, and rapidly established a number of traditional wintering areas during that decade.
The next comprehensive figures are reported by Schepers et al. (1998) based on waterbird counts from January 1997 in the Saloum delta and along the Petite Côte. The team counted a total of 858 Audouin’s Gulls between Dakar and the delta, with the majority (673) found in the Saloum, and 185 along the Petite Côte. They estimated the wintering population to number around 1,000 birds, while in 1988 the same areas (incl. Saint-Louis) held at least 80, but more likely at least 130 Audouin’s Gulls (Delaporte & Dubois 1990, though Baillon & Dubois in 1991 estimated the number of wintering birds to be around 500, without providing further details). Regardless, these numbers suggest that Ichtyaetus audouini continued to increase in numbers throughout the late eighties and nineties, and confirmed that Senegal plays an important role for the species during its non-breeding cycle.
2000 – 2017 – stability
Fast-forward a few years to the first decade of the 21st century: hardly any published data! The only citations of the species that I could find are from seawatch sessions and a few trip reports. For instance from 2006, when a Swedish team counted migrating birds off Ngor, from 10–14 and 25–26 November: 28 Audouin’s Gulls were noted on three separate days (Strandberg & Olofsson 2007). A year later, a more comprehensive migration study at Ngor, with impressive numbers of seabirds counted from 5-28 October, resulted in a total of 692 birds. In the Senegal delta, a maximum of c.15 birds were counted in 2002 (Triplet et al. 2014).
In January 2011, some 50 Audouin’s Gulls were counted by Ottvall et al. at Lac Rose, providing “more evidence of the increasing numbers […] wintering along the coast north of Dakar.” Later that year, Paul Robinson reports two 2nd calendar years from Lac Tanma, which seems to be the first mention of the species here (I’ve seen two birds on 28/8/16 here, but not during other visits in 2015-17). Paul also recorded the species in Popenguine, where on 12/2/12 the pond had “a few” Audouin’s gulls amongst the gulls.
In July 2012, Paul counted c.150 Audouin’s Gulls at Technopole, noting that these were “all sub-adult birds from 2010 and 2011, represents a real increase in summering birds south of the Sahara and a West African summer record count. Several had Spanish rings.” Indeed, Audouin’s Gull can now be seen year-round in Senegal.
Ngoné and colleagues estimated the Palmarin “winter” population to number 445 individuals (278 adults, 167 immatures) based on the modelling they performed on their monthly counts and ring recoveries from the end of 2013 up to end 2015. This seems rather on the low end given that at peak times in October they recorded up to around 700 birds, and that in recent years it’s easy to find more than 300 birds together in the lagoons along the Samba Dia road – surely there are many others scattered throughout the western Saloum delta, e.g. around Sangomar and further south. More on the findings of their study, which was presented under the form of a poster at last year’s PAOC, will be discussed further down.
Current distribution in Senegal
The winter range of the species in Senegal probably hasn’t changed much in the last 20-30 years, with the following areas being regularly used by Audouin’s Gulls:
- La Grande Côte: Langue de Barbarie and elsewhere in the Senegal delta around Saint-Louis (shores, beach and lagoons), though never in large numbers, with a maximum of c.65 birds in Jan. 2013 (Triplet et al. 2014). On the southern end of the coast, the species is regularly seen at Lac Rose and sometimes at Lac Tanma. It probably also occurs along the beach throughout (I need to ask Wim about this!), especially around the larger fishing towns and villages: Kayar, Mboro, Lompoul, etc. At Lac Rose, ca. 350 birds were seen on 11/2/18, suggesting that this is still an important roosting site for the species, at least during part of the northern winter.
- Cap-Vert peninsula: Regular at Lac Rose (e.g. c.60 on 8/8/15, 2 on the beach on 22/1/17, 5 on 14/5/17) and Technopole, where most numerous in January-March, but records from all months except for September (when I rarely visit Technopole); so far my highest count has been a modest 50 birds on 12/3/17. Birds are also regularly seen from Ngor, either migrating or, more often, feeding out at sea. In autumn and winter, one should be able to see Audouin’s Gull pretty much all along the coast from the Pointe des Almadies along Yoff all the way to Lac Rose. I really need to check out the Hann bay from time to time, as there are often lots of gulls and terns. The species has also been reported from Yene-Bargny where is likely still a regular visitor, and may well be numerous at times (in autumn maybe? Birds may favour Technopole later in winter).
- La Petite Côte: the Somone lagoon seems to be the most regular site, but birds also show up at least irregularly at Popenguine and Mbodiene, and likely feeds off-shore along the entire coast here.
- Saloum delta: this is of course the main wintering area, that likely holds about 80% of the Senegalese wintering population. Birds are typically concentrated in the lagoons to the north of Palmarin, and do not gather far inland. It should also occur further south in the delta but I have no data from there.
- Coastal Casamance: the only record I know of is of two birds on 12/10/16 flying north along the beach at Diembering. There certainly are more records (though none on eBird nor observado.org) as Casamance must be the far end of their regular range, given the absence of sightings in nearby Guinea-Bissau.
In terms of population size, my own conservative guestimate puts the current number on 800-1,000 birds, so not any different than the 1,000 birds estimated to winter in Senegal in January 1997, which logically reflects the species’ stable global population trend.
Elsewhere in West Africa
Isenmann et al. (2010) enumerate lots of records for Mauritania, but little or no info is provided on the evolution of the wintering population in the country, probably because of a lack of historical data. The current status is that of a regular migrant and wintering bird, with at least several hundreds of birds along the coast. Far more birds are said to winter along the Western Sahara coastline. The Gambia is also part of its regular winter range, mainly on and around the Bijol Islands, Tanji Bird Reserve. In 2007/08, about 500 Audouin’s Gulls were counted there. The first Gambian record, as per Morel & Morel, is of a bird at the Bakau Lagoon on 21/2/82.
Surprisingly, the species hasn’t yet been seen in Guinea-Bissau, which is most likely right outside the regular winter area, but surely a few individuals must reach the NW corner of the country, and particularly the Bijagos, given that they are recorded at least from time to time (it would seem) in Casamance and that Gambia is less than a 100 km away from the border. My Oct. 2016 observation near Diembering was barely 20 km from the border and both birds were moving north… In Guinea, the first record was obtained just last year by gull expert Peter Adriaens, a first-winter near Cap Verga on 28/10. The lack of other records from Guinea (and Guinea-Bissau) most likely reflects the absence of observers in the country, rather than a real absence of Audouin’s Gull which surely must at least from time to time reach Guinean waters. This is not the case in relatively well-watched Ghana, where the species is a true vagrant: a first-winter on 13/1/14 was quite an unexpected first for the country, as it had not previously been reported south of Senegambia (Kelly et al. 2014). [note that the species certainly doesn’t winter in Gabon, contra BirdLife International’s species fact sheet].
Now, I still wanted to talk about the origin of wintering birds in Senegal and summarise current knowledge based on ringing recoveries, but my blog post is already getting a bit long… that part will have to wait for a second installment, hopefully a week or two from now.
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.
Early January we spent a night at one of the Lompoul “desert” camps with visiting friends, while a trip up North last November provided the opportunity to make a few en-route birding stops in this poorly known region of the Grande Côte, off the beaten birding tours track. Here are some of the highlights.
Lompoul is quite a well-known tourist attraction, and what is sold as a desert with “authentic” Mauritanian tents, camel rides and the 4×4 or quad tours (not the type of activity one would expect from an ecolodge!!) is obviously not necessarily my destination of choice… but the children all like it of course and it has to be said that one does get a bit of a Saharan feeling here. The vast stretches of sand dunes are impressive, and the sunsets are quite stunning: indeed quite a special place, albeit rather surreal.
That said, there are of course very few birds in the dunes…
…but lots of good stuff in the endless bush country around it!
I really love this type of landscape so I was keen to find out what birds are around, even more so after sampling a few of the local specials during our roadside birding stops back in November when we encountered the impressive Lappet-faced Vulture and the elegant Dark-chanting Goshawk:
Also seen in the area roughly between Kebemer and Darou (NE of Mboro) were Black Scimitarbill, Green Wood-Hoopoe, Blue-cheeked Bee-eater, Mottled Spinetail, Striped Kingfisher, obliging Northern Anteater Chats, delicately patterned Speckle-fronted Weavers, the spectacular Sahel Paradise-Whydah, and so on. Many of these were seen or heard during a particularly productive picnic break along the new Lompoul road during our travel from Dakar to the Djoudj (more on the northbound road trip with Frédéric Bacuez, including several pictures of the landscape and a full list of birds, on Ornithondar).
But let’s get back to Lompoul: in the dunes, we had a lone Tawny Pipit flying over, and a small group of what were probably Greater Short-toed Larks. The scarce trees here typically hold Subalpine Warbler, Woodchat Shrike, Beautiful Sunbird and of course the ever-present Laughing Doves. The Eucalyptus growth and scrub bordering the dunes has some additional migrants like Common Chiffchaff (or was it an Iberian?), plus goodies such as Rufous-tailed Scrub-Robin – presumably the resident African (sub-)species – Green Bee-eater, Long-tailed Nightjar and Spotted Thick-knee. I also came across one of the few snakes I’ve seen so far in Senegal, the Elegant Sand Racer (Psammophis elegans), an inoffensive long and thin snake. Got close-up views in far more natural habitat than the empty swimming pool of the abandoned Hôtel du Lac at Mboro where Fred and I found one in November (it was still there last week!). Shortly before nightfall, a group of 14 Black Kites flew low over the tented camp, so I assume they came in to roost for the night somewhere nearby.
Further away from the dunes, out in the savanna, Bush Petronia was a real surprise given that western Senegal is not known to be part of the species’ range. I encountered several small flocks (3-5 inds.) including at least one singing male, and even managed to get a reasonable sound recording despite the windy conditions. This species – apparently now dubbed the rather unlyrical and unimaginative Russet-browed Bush-Sparrow (HBW) – is known for its nomadic habits, wandering widely outside the breeding season and thus rather unpredictable to find. I actually only saw it for the first time barely a year earlier, near Bamako. Fred confirmed that he hasn’t seen any of these little sparrows (quite literally… they’re called Petit Moineau in French) in the Saint-Louis and Gandiol hinterland, which is fairly similar to the habitat in Lompoul. I did find however a mention of Bush Petronia from Trois-Marigots in a Birding Breaks trip report, on 16.01.10. [side note: it’s a shame really that most tour companies do not report their sightings anywhere other than in what are often very approximate trip reports. At a minimum, important records should be notified to the African Bird Club for inclusion in the “Recent Reports” so that they can be easily retrieved and referred to]
The same area held quite a few other savanna specials: a male Savile’s Bustard quietly walking on the edge of a field, Wattled and Black-headed Lapwings, Striped Kingfisher, Yellow-fronted Tinkerbird, Senegal and Yellow-bellied Eremomelas, Fork-tailed Drongo, Senegal Batis, Brubru, Green-winged Pytillia, Sudan Golden Sparrow, a Speckle-fronted Weaver, and several White-rumped Seedeaters. A Red-necked Falcon hunting over the hills was rather unexpected as there are few palm trees around. On the Palearctic migrants front, I saw Common Redstart, Bonelli’s Warbler, Common Whitethroat, Western Orphean and Subalpine Warblers, plus a group of 9 Eurasian Griffons (with one Rüppell’s Vulture) and a probable Common Kestrel.
Last but not least, in November we – well, my Swiss friends really – found an unexpected roadkill on the Lompoul-Kebemer road, close to the village of Diokoul, ca. 7 km west of Kebemer: a Golden Nightjar! This poorly known and rarely seen species in Senegal is probably on the edge of its distribution range here. It’s been reported from the Far North (Richard-Toll/Podor) and the Ferlo area, but also from further south in the Khelkom region where a French group saw and recorded at least one bird last year. Maybe one day I’ll hear or even see this spectacular nightjar, hopefully in a better shape than this unfortunate individual…
Rather surprisingly for a road with very little traffic, we encountered quite a few other road kill (mainly on 18/11/16 with Cyril and Manolo), including two rarely seen mammals: Pallid Fox and Genet. Also a Spotted Thick-knee, numerous Abyssinian Rollers, Laughing Dove, Chestnut-bellied Starling, and surely several others that went unnoticed or which we didn’t stop to identify.
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.