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ATLANTIC
SEABIRDS
Contents and abstracts issue 2(2)
published December 2000
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Glass N., I. Lavarello, J.P. Glass & P.G. Ryan 2000.
Longline fishing at Tristan da Cunha: impacts on seabirds.
Atlantic Seabirds 2(2): 49-56.
Tristan da Cunha and Gough Islands in the central South Atlantic Ocean support globally important seabird populations. Two longline fisheries
occur within Tristan’s Exclusive Economic Zone: a pelagic fishery for tunas and
a demersal fishery for bluefish and alfoncino. Fishery observers have
accompanied all three licensed demersal cruises. Despite attracting
considerable numbers of birds and setting lines during the day, only one bird
(a Great Shearwater Puffinus gravis) was killed (mortality rate 0.001 birds per 1000 hooks). By
comparison, the pelagic fishery for tuna, which exceeds demersal fishing
effort, probably has a much greater impact. Observations aboard one vessel in
mid-winter suggest a bycatch rate of >1 bird killed per 1000 hooks; this
could be even higher in summer when more birds are breeding at the islands.
Stricter regulations are required for pelagic vessels, including routine
placing of observers on board. The gravest threat posed by longline fishing to
Tristan’s seabirds comes from vessels fishing illegally in Tristan waters, as
well as vessels in international waters that do not use basic mitigation
measures. There is a pressing need for better policing of Tristan’s waters.
Piersma T. 2000. Age
asymmetries in the aerial display of Little Gulls Larus minutus.
Atlantic Seabirds 2(2): 57-67.
Aspects of age differences
in the aerial display of Little Gulls Larus
minutus are described based on fieldwork carried out
in May 1983 in the Lauwersmeer area, The Netherlands. Aerial displays occur
when an initiator or 'sender' approaches a 'receiving' individual. The sender
initially makes (individually identifiable) kay notes, followed by several ke-kèh repeats. Once the sender has approached the receiver to within a few
meters, it increases flight speed, jerks up the head to almost a vertical
position whilst starting to call a repeated ke-kôo. The head-up part of the display is rounded
off with a short glide over the receiver, but often the display is aborted
somewhere along the sequence. This is especially the case when immatures are
the initiators. Immatures seem particularly keen to exercise the display, and
when doing so preferentially act towards adults. During display flights between
adults, receivers tended to respond with their own display flights. However, in
aerial interactions initiated by immatures the receivers tended to either flee
or to retaliate by attack. I suggest that the aerial display presents a
compound quality signal (possibly derived from aerial mosquito-catching
movements), that requires much physical and social practising, even during the
immature stages of life.
Zonfrillo B. & R.L. Palma 2000. The feather lice of the
Levantine Shearwater Puffinus yelkouan and its taxonomic status.
Atlantic Seabirds 2(2): 68-72.
Four species of feather
lice (Insecta: Phthiraptera) were found on one fresh dead and five museum skins
of Levantine Shearwaters Puffinus yelkouan from various localities in
the Mediterranean. Two of them, Halipeurus diversus (Kellogg, 1896) and Saemundssonia
(Puffinoecus) kosswigi Timmermann, 1962 (unique to P. yelkouan),
had been recorded previously from this host; the other two, Austromenopon
paululum (Kellogg & Chapman, 1899) and A. echinatum Edwards,
1960, represent new host-louse records. One bird collected fresh in Cyprus
yielded the most lice, including 20 specimens of A. echinatum. The
taxonomic position of the Levantine Shearwater is discussed briefly and the
opinion that it be regarded as a distinct species is supported.
Ratcliffe N., F.J. Zino, P. Oliveira, A. Vasconcelos,
C.J. Hazevoet, H.C. Neves, L.R. Monteiro & E.A. Zino
2000. The status and distribution of Fea’s Petrel Pterodroma feae in the
Cape Verde Islands. Atlantic
Seabirds 2(2): 73-86.
A census of Fea’s Petrel Pterodroma
faea was conducted in the Cape Verde Islands
during January and February 1998. Counts were made on three of the four islands
where the taxon has historically been known to breed: Fogo, São Nicolau and
Santo Antão. The persistence of those colonies previously reported on these
islands was confirmed and several undocumented colonies were located. The
population on Fogo was c. 80 pairs,
on São Nicolau c. 30 pairs and
that on Santo Antão c. 200
pairs. The surveys of Fogo and Santo Antão were incomplete, so the population
size could be higher there than indicated by the present data. No survey of Santiago
was attempted and further surveys are needed to establish the status of Fea’s
Petrel in the Cape
Verde Islands
as a whole. The colonies on Santo Antão and São Nicolau were generally situated
on inaccessible cliff faces above dry river valleys, while those on Fogo were
among boulders in dry river beds, among rubble and tubes in old lava flows and
on cliffs. Fea’s Petrel continues to be threatened by human exploitation and
predation by cats and rats, particularly on Fogo and some areas of Santo Antão
where the colonies are most accessible.
Short notes
Camphuysen C.J. 2000.
Seabirds drowned in fishing nets off Jan Mayen (Greenland Sea). Atlantic
Seabirds 2(2): 87-91.
Bits and pieces of fishing
nets found at Jan Mayen island (central Greenland Sea) often contain entangled remains of seabirds. Brünnich's Guillemots Uria lomvia
and Little Auks Alle alle alle were the commonest species encountered, but also Atlantic Puffin Fratercula arctica naumanni and Northern Fulmars Fulmarus glacialis were found. Pieces of coarse trawl nets and
fine gill nets were found. It is unclear if the birds drowned when the nets
were still in use, or if the birds drowned in ghost-nets. Only few and brief
visits were made on Jan Mayen's beaches between 1983 and 2000, but the
frequency of finds suggests strongly that substantial numbers of seabirds drown
in fishing gear around this remote island in the North Atlantic.
Harris M.P., J. Bull & S. Wanless 2000. Common Guillemots Uria aalge successfully feed
two chicks. Atlantic Seabirds 2(2): 92-94.
A pair of Common Guillemots
Uria aalge with a small chick adopted a second and successfully reared
both to normal fledging age. A single day's feeding watch suggested that the
pair doubled the normal feeding rate and the adults spent little time together
at the nest-site, though the chick was never left unattended.
News and notices
[Book review] Tickell W.L.N. 2000. Albatrosses. Pica
Press, East Sussex (reviewed by J.P. Croxall)
[News] Steve Geelhoed joins editorial board