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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. 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 8.054 during 3-16th October 2005 and
second highest total beeing 4.802 on 6-16 October 1996.
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..
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 1.893,
of which the latter figure were recorded between 3-16th October
2005 (the second highest total beeing 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 275 on each session
between 1995 and 2005 (the latter figure recorded between 3-16th
October 2005). The highest daily total was 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 400 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. 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 289 migrating birds
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.
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 was 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.
October 2005: 1539 recorded at Calao and 361 from N'gor. The second
highest total recorded. Many flocks were distant, of the closer
birds seen not more than 10% were first year birds (which arrive
later in October and November). At sea: At least 70 on 6th (one
flock of 20 birds lying on sea close, also heard calling) and 15
on 13th.
The largest flock seen consisted of over 100 birds
on 6 November 1998 nad in October 2005. 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 a total of 131 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
count, 7.839 birds, was 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 19 birds were recorded from the terrace
of Calao during 3-16th October 2005. One first year bird and the
rest adults. 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
14-27 October 2003 a total of 10.555 Common/Arctic Terns was counted,
of which approximately 95% 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.
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.
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 23.923 Black Terns passing south-west
on 6-16 October, with 12.645 on 12 October. The Swedish team counted
a total of 10.794 on 14-27 October 2003. Dense flocks of up to 100
birds were then seen on several occasions. 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)
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)
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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