Transparent utfyllnad Seabird species seen off N'Gor in autumn

Some of the species listed below are those that are most likely to be seen when seawatching at N'Gor. How many species and in what numbers you will see in one or two week stay largely depends on which time of year you visit Senegal. The ultimate time for a great mix of seabirds on migration is probably between the beginning of October and the middle of November. However, it is obvious that there is still much more to be learnt about the subject, especially regarding migration patterns and peak days for each species.
   If you compare the land-based and pelagic totals between the years (see the 'Seabird totals' section), you will discover great differences in annual numbers of each species. So, this is not a complete list, but serves more as an introduction, useful to have in mind when exploring the waters off Senegal.
This page was updated on 22nd October 2008  

Bulwer's Petrel Bulweria bulwerii
The first record for Senegal was off Dakar in autumn 1990. Since 1994, the species has been observed in small numbers of between 1 and 10 birds annually. In October 2003 and 2005 a total of 18 and 30 Bulwer's were recorded respectively. But all time high was recorded in October 2007, with not less than 65 birds passing by Calao on 11th October!As the species leaves its breading grounds in Macaronesia in September it would not come as a surprise if coverage at N'Gor earlier in the autumn produced higher numbers of this species. It also breeds on the Cape Verde Islands with less than 100 pairs.

Scopoli's Shearwater Calonectris diomedea diomedea
The Mediterranean form (of Cory's) is rarely seen (or, rather, perhaps overlooked) passing off the Cap Vert peninsula. It has not been observed annually in autumn, but a few birds were recorded in for example 2001 and 2003.
   Winters in South African Atlantic waters, with some in the Red Sea and the western Indian Ocean.

Cory's Shearwater Calonectris diomedea borealis
Usually the most numerous subspecies of the Calonectris complex in October and November, but its occurrence is unpredictable. For example, 5.800 Calonectris Shearwaters were seen off the Cap Vert peninsula on 10th-12th November 2001, with an estimated 95% Cory's Shearwaters and less than 5% Cape Verde Shearwaters. The Swedish team could not positively identify a single bird as belonging to this subspecies in October 2003, but they did so in October 2005. Between 10-14th and 25-26th November 2006 a total of 12.000 passing birds were recorded at N'Gor, but probably 15.000 only on 10th November (at least 7.000 birds was counted during 7:20 hours).
   The size and jizz of Scopoli's and Cory's Shearwaters are very similar and they are difficult to distinguish in field, especially compared to Cape Verde Shearwater which is a more straightforward identification matter.
   Winters in Argentinean and Brazilian waters. Immatures move north in spring to the western North Atlantic, then take an easterly route when heading back south. Vagrant to South Africa.

Cape Verde Shearwater Calonectris diomedea edwardsii
Breeds exclusively on the Cape Verde Islands with a population estimated at 10.000 pairs in the beginning of the 90's (but probably decreasing steadily). The numbers off the Cap Vert peninsula clearly vary between the years and the absolutely highest numbers have been observed in the vicinity of trawlers off Senegal. On 3 November 1997 about 4.500 were seen at sea, but the highest total for a single day is 6.000 and 6.500 at sea on 4 and 6 November 1998 respectively. These birds may be wandering immatures or non-breeders.
   The wintering grounds are unknown. Immatures gather off the West African coast in autumn. Observations have been claimed from the Canaries and Madeira, but it is unclear whether they have been accepted by the relevant bodies.

Great Shearwater Puffinus gravis
Rarely recorded off Senegal in October and November. In total seven birds were seen at sea between 2-6 November 1998, and 8 birds were passing off the Calao's terrace on 25th November 2006 (+ 3 birds the day after), which is the highest total recorded. As this species southward migration primarily takes place in August and September along Western Europe (Ireland) and the Macaronesian islands, its occurrence off Cap Vert peninsula is probably missed as most seawatchers visit Dakar later. The migration pattern of this shearwater off Senegal is an interesting topic for future seawatchers to delve into! Is the Great Shearwater a regular migrant off Senegal, or does it use another route?

Sooty Shearwater Puffinus griseus
One of the most numerous migrating shearwater species in autumn. Difficult to count accurately as it never passes in flocks, but rather in singles or small loose groups. The three highest daily counts during the last two decades is 1.839 on 7 October 2005, 1.765 on 6 October 1996 and 1.315 on 30 October 1997. The highest total for land-based seawatching is 9.739 on 5-28 October 2007 and second highest total beeing 8.054 on 3-16th October 2005.
   This is another Subantarctic breeder that probably passes Senegal in larger numbers during September, but that remains to be confirmed in the future.

Manx Shearwater Puffinus puffinus
Scarce migrant in October and November. In this period it has never reached three-figure totals. A total of about 20 to 50 birds passing westwards off N'Gor seem to be a normal number during each seawatching period the last ten years, but the highest total beeing 110 birds during 3-16th October 2005. Perhaps this species appears in larger numbers in September, a few weeks after its migration peak along the British and Macaronesian ilands?

Balearic Shearwater Puffinus mauretanicus
Rare, but regularly recorded. The all-time high is ten birds passing between 30 July and 5 September 1990. A normal total for a seawatching session during October-November seems to be 1-2 birds each year. The majority return to the Mediterranean in October to November, after summering (and moulting) in the Atlantic, mainly in the Bay of Biscay.

Little Shearwater Puffinus assimilis boydi
Scarce but regularly seen. All birds have been identified as the subspecies boydi (also known as Boyd's Shearwater or Cape Verde Little Shearwater), which breeds on the Cape Verde Islands where the population is estimated to amount to several thousands of pairs. It is distinguished from the Macaronesian race baroli, by having dark undertail coverts, a dark cap extending below the eye and in lacking the pale panel across the secondaries. In this respect it is more similar to Audubon's Shearwater, which is a seabird of the Caribbean, the Persian Gulf and Indian Ocean. Little Shearwater of the race baroli is, however, rarely seen off Senegal.
   The numbers vary much between the years: from not a single bird in 2003 and up to 56 in the beginning of October 1997.

Wilson's Storm-petrel Oceanites oceanicus
The most numerous of the small Storm-petrels passing off the Senegalese coast, both in spring and autumn. The highest total recorded from land at N'Gor is 658 birds heading southwest between 14 and 27 October 2003. Another 503 unidentified Wilson's/European S-p's, of which the majority undoubtedly were Wilson's, were also recorded at that time. During the same period 161 Wilson's was recorded on pelagic tours. The second highest total comes from 1996, when 330 were seen from both land and at sea.
   Noteworthy of mention is 1.259 passing north on four days in April 1992.

European Storm-petrel Hydrobates pelagicus
Scarce, but a regular migrant. The Swedish team had great luck with this species in October 2003. They recorded 7 birds from Isle N'Gor and 52 from two pelagics off the Cap Vert Peninsula. Between 1995 and 1997 (a total of four seawatching periods) British birders only saw this species on their pelagic trips, with a highest total of 14 birds on 5 tours/days at sea 1995. Interesting! It seems that you have to coincide with the right period and also a lucky day within the period to see this species side by side with Wilson's.
   The question for future seawatchers remain: Is this species – along with Leach's and Madeiran Storm-petrel – as scarce as the counts so far indicate? Does it occur at other times? Or have the days chosen for pelagic tours been the wrong ones?

Leach's Storm-petrel Oceanodroma leucorhoa
The highest totals recorded by the British birders between 1995-1997 and 2001 were 48 (only at sea in 1995) and 43 (of which 40 were seen from land) in 1997. The Swedish team recorded 33 birds in 2003, only at sea and all of them turned up about 1 ½ hours travel from land. In addition, 91 unidentified Oceanodroma-Storm-petrels were recorded at sea, of which the majority probably were Leach's.

Madeiran (Band-rumped) Storm-petrel Oceanodroma castro
A rarely seen species off Senegal in October and November, according to the British seawatchers in the last decade. The highest total, 19 birds, was recorded at sea by the Swedish team in 2003. They were seen side-by-side with Leach's Storm-petrels 1 ½ hours distance from land, over deeper waters off the continental shelf. Three of the five unidentified Oceanodroma-Storm-petrels passing Isle N'Gor were probably this species, according to the lower and more Shearwater-like flight style, the seemingly all-dark plumage and jizz. Do not expect every Leach's or Madeiran S-p's to be easy to identify at sea (or from land)!
   The closest known breeding grounds are located on the Cape Verde Islands and the population there is estimated at 1.000 pairs. Birds seen off Senegal could also be migrants of Macaronesian origin or wandering immatures and/or non-breeders. One interesting questions remain: Why did all 19 identified birds seem to be in a fresh plumage, compared to the many moulting Leach's?

Red-billed Tropicbird Phaethon aethereus
A few pairs breed on Isle Madeleine, four kilometres south-west of Dakar. Singles (probably in local movements) could be seen off N'Gor now and then during seawatching, always passing high above sea.

Brown Booby Sula leucogaster
Rare, but regularly seen off N'Gor. These birds probably stem from the breeding population on the Cape Verde Islands, which is estimated at about 1.000 pairs.

Northern Gannet Morus bassanus
Scarce, but regularly seen off N'Gor. All five birds recorded in 2003 were juveniles. The totals between 1995 and 2001 differ from 3 to 242 birds (with 205 seen at sea on 7 November 1998). However, the highest total recorded from land at N'Gor is 295 heading south on 10 January 2001. Allegedly occurs with breeding pairs on Isle Madeleine, but there is no photographic evidence and the location seems to be far south for breeding Gannets!

Grey Phalarope Phalaropus fulicarius
Regular migrant off the Cap Vert peninsula. As one of the co-authors of the book 'Flight Identification of European Seabirds' I, at last, realised that this species is both a wonderful and true seabird! Sorry for not including it in the book! However, it took some time to understand that those loose flocks of auk-like, pale and fast flying petrel look-alikes were, in fact, not big and fat Sanderlings! The best way to identify this species is the pale grey plumage and (definitely) the flight style. A very greyish pale, small, petrel-like wader with a chubby body resembling an auk and showing a distinct white upper wing-bar, especially on the inner wing. Wingbeats are deliberate and continuous at 2-3 per second in moderate wind, accompanied by a constant, petrel-like, slow side-to-side jinking. Do not focus on trying to perceive its dark eye-mask at a distance, as it is hard or impossible to discern.
   The numbers seen off N'Gor in autumn differs a lot, from five up to 1.556 birds during the last two decades of seawatch. The highest daily count is 215 birds passing west on 10th October 2007.

Pomarine Skua Stercorarius pomarinus
The most numerous of the skua species. Most large-scale movements seem to be during north-westerly and northerly winds, with some large daily totals: 3.199 on 1 November, 845 and 887 on 2 and 3 November 1997; 1.383 and 897 on 10 and 12 October 1996. A normal total for a seawatching period in October lies between 2.000 and 3.000 passing Poms, but the all-time high is 6.233 on 28 October to 4 November 1997. In 2003 hundreds of very distant and unidentified skuas passing were not counted.
   Compared to Arctic Skua this species normally passes in larger flocks at varying altitudes normally 1-2 kilometres off the coast, whereas most Arctic pass closer inshore in groups of 3-5 birds. About 90% of all passing birds in October to mid November are adults, some 5-8% immatures and 1-2% juveniles. Does the juveniles pass by in late November and December? By the way, many adults still show their lovely tail projection in October-November.

Arctic Skua Stercorarius parasiticus
Numerous, but does not amount to near the numbers of Pomarine Skua. The totals for each seawatching period varies between 476 and 2.879, of which the latter figure were recorded between 5-28th October 2007, followed by 1.893 on 3-16th October 2005 and 1.640 on 14-27 October 2003. Normally most Arctic Skuas pass close to the coast and this migration is best witnessed from Calao's terrace. On Isle N'Gor, the Arctics often pass too close and are easy to miss if you scan the sea with the scope all the time. In 2003 the ratio of ages was the same as for Pomarine Skua, with adults in absolute majority. Approximately less than 50% was juvenile and immature birds in October 2005. The variations in plumage of moulting adults is surprising and very interesting. Compared to Pomarine Skua, it passes in much smaller groups, consisting mostly of 3-5 birds.

Long-tailed Skua Stercorarius longicaudus
Normally the less numerous of all skuas seen off N'Gor in October and November. The totals vary from 10 up to 864 on each session between 1995 and 2008 (the latter figure was recorded between 5-28th October 2007). The highest daily total is 123 on 27th October 2007, followed by 116 on 28th October 2008 and 90 birds passing south on 15th October 2005. In 2003 the majority (about 60%) were juveniles and 40% were adults (including a few immatures) that had moulted into a characteristic winter plumage and all adults seen had lost their tail-streamers. In 2005, when the seawatch started in the beginning of October about 90% of the birds were juveniles. Singles or small groups of 2-3 birds is often seen, somtetimes together with Pomarine or Arctic Skuas.

'Great' Skuas Catharacta sp.
About 100 to 800 have been recorded at each session over the years, all flying south without exemption. But the main question is still unanswered: Which species is/are involved? The British birders who have visited N'Gor over many years are not sure, but suspect many to be South Polar Skua. This has generated some debate in recent years, with suggestions that some (photographed) might be immature Great Skuas or even Brown Skua, which includes a few subspecies. On the 'Resources' page you will find links to Dick Newell's excellent web site including a vast numbers of photos on Catharacta skuas seen off Senegal, as well as many photos on identified birds photographed in the Antarctic. Perhaps future DNA-samples of captured birds can solve the issue and give some answers of which species is involved off Senegal.

Grey-headed Gull Larus cirrocephalus
Scarce but regular on passage. All of the eight birds recorded in October 2003 flew west through the strait, in similarity to the Black-headed Gull and Slender-billed Gulls. In October 2007 a total of 34 birds was recorded. All birds had been missed if the Swedish birders had seawatched from the north side of Isle N'Gor, but from Calao's terrace the coverage of all birds that pass through the strait was total.

Audouin's Gull Larus audouinii
Except for Sabine's Gull, this species is the most numerous gull species in the area. The highest total beeing 692 on 5-28th October 2007, followed by 289 on 6-16 October 1996, 59 on 14-27 October 2003 passing south (except many towards north and north-east) and 77 between 3-16th October 2005. Besides obvious migrants, stationary and foraging birds are seen daily with up to 15-20 birds a day. Juveniles moulting to first-winter plumage are commonest, followed by 2nd cal and 3rd cal year birds. The Swedish team saw only one adult in October 2003 and two in 2005, but several in October 2007.

Lesser Black-backed Gull Larus fuscus
Scarce but regular on passage. The totals vary much over the years, from 0 to 16. All birds seen in October 2003 were subadults and adults of graellsii/intermedius.

Kelp Gull Larus dominicanus
Scarce, but seems to be regular in the area as it moving northwards in autumn. A total of 20 birds towards both west and (a few) east were seen in October 2003. Most seem to be near-adults or older immatures.

Sabine's Gull Larus sabini
Definitely the most numerous gull species at N'Gor in September to November. The highest total ever is 6.724 on 5-28th October 2007, followed by 3.356 passing Isle N'Gor and 144 seen at sea on 6-16 October 1996. The highest daily counts were 804, 1.107 and 932 on 6, 10 and 12 October 1996 respectively.
   The largest flock seen consisted of about 120 birds close to Calao in delightful conditions on 5th October 2007. Two more flocks consisting over 100 birds were recorded in October 2007. The vast majority are adults in winter plumage, juveniles only accounting for 20-30% in September and first half of October. The heaviest passage seems to occur in northwesterly winds.

Caspian Tern Sterna caspia
Scarce but regular on passage. The totals during each period between 1995 and 2001 varies from 0 to 9 birds only. The main reason for the low numbers may be that the British birders have counted from the north side of Isle N'Gor. In October 2003 the Swedish team used the newly discovered terrace at Calao as a seawatching spot, from where you also see all birds that pass through the strait between the mainland and Isle N'Gor. In 2003, a total of 51 Caspians were recorded and 49 of these passed through the strait, with only two off Isle N'Gor. During 3-16th October 2005 and 5-28th October 2007 a total of 131 and 147 respectively were recorded, almost exclusively seen from the terrace at Calao.

African Royal Tern Sterna maxima albididorsalis
A less numerous migrant with up to 200 birds recorded in October over the years. Between 30 July and 5 September 1991, French birders recorded a total of 3.500 birds (but only 17 Lesser Crested Terns). Up to 30 non-migrating birds were seen daily off the N'Gor area in October 2003, foraging with Lesser Crested and Sandwich Terns. During 3-16th October 2005 a total of 432 were recorded, almost exclusively seen from the terrace at Calao (393 birds!).
   Note: It was not always easy to distinguish adults in winter plumage from Lesser Crested, especially when seen without direct comparison to a well-known species.

Lesser Crested Tern Sterna bengalensis emigrata
A less numerous migrant with up to 200 birds recorded during in October through the years. Besides migrants, there are always many birds foraging inshore with Royal and Sandwich Terns. About 30-50 non-migrating birds were seen daily off the N'Gor area in October 2003. However, during 3-16th October 2005 a total of 825 were recorded, almost exclusively seen from the terrace at Calao.
   This race breed along the Libyan coast in the Mediterranean Sea and winters along the West African coast. The race is slightly paler than the eastern races between East Africa and India; Sterna bengalensis bengalensis (Red sea) and S. b. torresii (Persian Gulf).

Sandwich Tern Sterna sandvicensis
Numerous migrant, but never reaching the numbers of Arctic, Common and Black Terns. Many pass close inshore of Isle N'Gor as well as through the strait and are therefore easy to miss. The highest total is 11.075 on 5-28th October 2007, followed by 7.839 birds in October 2005 (and 2.100 in October 2003).

Roseate Tern Sterna dougallii
Scarce but regular on passage in October, probably more numerous in September. The numbers in October vary much, from 0 to 68 birds. The latter all-time high was recorded from both land and sea on 6-16 October 1996. A total of 49 birds was recorded on 5-12th Oct ober 2008 and 19 birds were seen from the terrace of Calao on 3-16th October 2005. All passing through the strait inside Ile N'Gor.

Common Tern Sterna hirundo
Together with Black Tern, the most numerous tern in October. A total of 6.454 passing southwest was recorded on 4-11 October 1997. On 5-28th October 2007 an incredible total of 48.184 Common/Arctic Terns was counted, of which approximately 70% were Common Terns. The Swedish team did not pay too much attention to the 'Comic' Terns in 2003 and many that passed close to Isle N'Gor or through the strait were certainly missed.

Arctic Tern Sterna paradisaea
Probably the most numerous tern species in August to September. In 1991, the French team recorded 15.300 Arctic Terns off the western tip of the Cap Vert peninsula, of which the majority passed in September. On Common Tern peak days in October, Arctics represented about 5% of the total 'Comic' Terns. However, in October 2007, Arctic Tern was the most numerous tern specie.

Bridled Tern Sterna anaethetus
Rarely seen at N'Gor, but a few pairs breed regularly on the islets of Madeleine southwest off Dakar. On 12 and 14 October 1996 six birds were seen (five plus one bird flying south). In October 2005 singles (1+1) were seen passing Calao and N'Gor respectively. Six and a single was recorded in October 2007 and 2008 respectively.

Little Tern Sterna albifrons
Regular migrant. The highest total is 280 birds recorded during 3-16th October 2005 (Calao 253 and Ngor 27). The second highest total recorded ever is 143 birds passing on 6-16 October 1996. Probably a more numerous migrant in September.

Black Tern Chlidonias niger
Probably the most numerous tern species between mid September and mid October. The highest figure is 29.309 passing south-west on 5-28th October 2007, followed by 23.923 on 6-16th October 1996, of which 12.645 was recorded on 12 October. At midday many flocks often gather off the coast to forage, such as in October 2003. All birds seen were adults in winter plumage or juveniles.

Rare or scarce seabird species recorded:
Fea's Petrel Pterodroma feae (Scarce)
Cape Gannet Morus capensis (Very rare)
White-faced Storm-petrel
Pelagodroma marina (Rare)
Slender-billed Gull Larus genei (Regular in small numbers)
Black-headed Gull Larus ridibundus (Rare)
Mediterranean Gull Larus melanocephalus (Scarce)
Laughing Gull Larus atricilla (Rare: One record on 7th October 2008)
Franklin's Gull Larus pipixcan (Rare: One record on 5th October 2008)
Yellow-legged Gull Larus michahellis (Scarce)
Little Gull Larus minutus (Rare)
Black-legged Kittiwake Rissa tridactyla (Rare)
Gull-billed Tern Sterna nilotica (Scarce)
Whiskered Tern Chlidonias hybridus (Rare)
White-winged Black Tern Chlidonias leucopterus (Scarce)
Sooty Tern Sterna fuscata (Scarce: Two records in October 2007)
Black Guillemot Cephus grylle (One record: A single off Calaon 11-12th October 2008. The first for Senegal and West Africa!)

Additional references:
1. The Complete Birds of the Western Palearctic (CD-ROM). Perrins C.M. et al., 1998. Oxford University Press, Oxford.
2. Björn Johansson, Sweden, who has provided useful information from his seawatching trip on 1-8 November 1998 (with Wildwing Tours).

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Bulwer's Petrel at sea off N'Gor.
Photo: Göran Ekström, 2003

Cory's Shearwater off Madeira.
Photo: Göran Ekström, 2002

Cape Verde Shearwater off N'Gor.
Photo: Göran Ekström, 2003

Cape Verde Shearwater off N'Gor.
Photo: Göran Ekström, 2003

Sooty Shearwater off N'Gor.
Photo: Göran Ekström, 2003

Wilson's Storm-petrel off N'Gor.
Photo: Göran Ekström, 2003

European Storm-petrel off N'Gor.
Photo: Dan Mangsbo, 2003

Leach's Storm-petrel off N'Gor.
Photo: Dan Mangsbo, 2003

Red-billed Tropicbird at Madeleine.
Photo: Dan Mangsbo, 2003

Adult Pomarine Skua off N'Gor.
Photo: Göran Ekström, 2003

Adult Arctic Skua off N'Gor.
Photo: Göran Ekström, 2003

Juvenile Long-tailed Skua off N'Gor.
Photo: Göran Ekström, 2003

Unidentified Catharcta skua.
Photo: Dan Mangsbo, 2003

Second winter Audouin's Gull.
Photo: Göran Ekström, 2003

Sabine's Gull in winter plumage.
Photo: Dan Mangsbo, 2003

Adult African Royal Tern in winter.
Photo: Göran Ekström, 2003

First winter Lesser Crested Tern.
Photo: Göran Ekström, 2003

Juvenile Common Tern.
Photo: Göran Ekström, 2003

Juvenile Arctic Tern.
Photo: Göran Ekström, 2003

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