EUROPEAN SHAG
(Phalacrocorax aristotelis)
BODY LENGTH: 72 cm DEEPEST DIVE: 61 m (REF 3)
WING SPAN: 97 cm LONGEST DIVE: 163 s (REF 2)


ISLE OF MAY (56°11'N; 02°33'W) TOP
1989: Dive depth: 33 ± 1 m, max= 42 m (N=26 birds)
1989: (maximum depth gauge, 150mm long, 1.7g)
1989: Dive depth: 35.5 ± 0.9 m, max= 43 m (N=13 birds)
1989: (time-at-depth gauge, 90x11 mm, 11g)		 REF 1
1987-89: Dive duration: 62 ± 1.92 sec, max= 163 sec (N=31 birds)
1987-89: (radio-transmitter, 19g, 42x15 mm + 325 mm aerial)		 REF 2
1989: Dive depth: avg= 30.1 ± 2 m, max= 43 m (N=13 birds)
1990: Dive depth: avg= 19.7 ± 4.6 m, max= 45 m (N=14 birds)
1990: (Photographic time-at-depth recorder, 11g, 90x11mm)		 REF 3
1996: Dive depth: 20.5 ± 1.3 m, max= 34.6 m (N=21 birds)
1996: (Mk5 Wildlife Computers, 50 g, 60x35x15mm; 1m accuracy, sampling: 1s)		 REF 4
1997: Dive duration: avg= 63.3 ± 2.7 s (N= 40 birds)
1998: (radio-transmitter)
1998: Dive depth: avg= 27.2 ± 2.6 m (N= 19 birds)
1998: Dive duration: avg= 71.9 ± 2.9 s (N= 19 birds)
1998: (radio-transmitter + time-at-depth gauges)
2001: Dive depth: avg= 22.8 ± 1.1 m (N= 29 birds)
2001: Dive duration: avg= 62.4 ± 2.1 s (N= 29 birds)
2002: Dive depth: avg= 20.6 ± 0.8 m (N= 48 birds)
2002: Dive duration: avg= 58.2 ± 1.3 s (N= 48 birds)
2003: Dive depth: avg= 26.7 ± 2.2 m (N= 8 birds)
2003: Dive duration: avg= 68.8 ± 3.5 s (N= 8 birds)
2003: (PreciTD temperature depth loggers, sampling= 2 s)		 REF 5
SUMBURGH HEAD (59°51'N; 01°12'W) TOP
1990: Dive depth: avg= 32.2 ± 13.4 m, max= 61 m (N=6 birds)
1990: (Photographic time-at-depth recorder, 11g, 90x11mm)		 REF 3
LUNDY ISLAND (51°10'N; 4°40'W) TOP
1990-92: Dive duration: avg= 43.6 ± 15.8 s (N=745 dives)
1990-92: (Observation from land by naked eye and binoculars + stopwatch)		 REF 6
SKOMER (51°44'N; 05°17'W) TOP
1976-82: Dive duration: avg= 38.4 ± 7.8 s, max= 50.8 s (N=50 dives)
1976-82: (Observation from land by binoculars + stopwatch)		 REF 7
CHAUSEY ISLAND (48°55'N; 2°50'W) TOP
1994-95: Dive duration: avg= 38 ± 2.23 s (N=5 birds)
1994-95: (TW3 VHF transmitters, Biotrack, 18g, 30x20mm + 2 aerials 280 & 230mm)		 REF 8
HORNØYA (70°22'N - 31°10'E) TOP
1989: Dive depth: avg= 28.1 ± 6.3m, max= 39.6 m (N=12 birds)
1989: (Capillary depth gauges, MicroLine, 1.02mm in diameter)		 REF 9

REFERENCES
REF 1 Wanless S, Burger AE, Harris MP (1991) Diving depths of shags Phalacrocorax aristotelis breeding on the Isle of May. Ibis 133: 37-42
REF 2 Wanless S, Corfield T, Harris MP, Buckland S, Morris J (1993) Diving behaviour of the shag Phalacrocorax aristotelis (Aves: Pelecaniformes) in relation to water depth and prey size. Journal of Zoology London 231: 11-25
REF 3 Wanless S, Harris MP, Burger AE, Buckland ST (1997) Use of time-at-depth recorders for estimating depth and diving performance of European shags. Journal of Field Ornithology 68: 547-561
REF 4 Wanless S, Finney SK, Harris MP, McCafferty DJ (1999) Effect of the diel light cycle on the diving behaviour of two bottom feeding marine birds: the blue-eyed shag Phalacrocorax atriceps and the European shag P. aristotelis. Marine Ecology Progress Series 188: 219-224
REF 5 Camphuysen C (2005) Understanding marine foodweb processes: An ecosystem approach to sustainable Sandeel fisheries in the North Sea. IMPRESS Report, Koninklijk Nederlands Instituut voor Onderzoek der Zee, Q5RS-2000-30864, Texel
REF 6 Lea S, Daley C, Bobbington P, Morison V (1996) Diving patterns in shags and cormorants (Phalacrocorax): tests of an optimal breathing model. Ibis 138: 391-398
REF 7 Cooper J (1986) Diving patterns of Cormorants Phalacrocoracidae. Ibis 128: 562-570
REF 8 Grémillet D, Argentin G, Schulte B, Culik BM (1998) Flexible foraging techniques in breeding cormorants Phalacrocorax carbo and shag Phalacrocorax aristotelis: benthic or pelagic feeding?. Ibis 140: 113-119
REF 9 Barrett RT, Furness RW (1990) The prey and diving depths of seabirds on Hornøya, North Norway after a decrease in the Barents Sea Capelin stocks. Ornis Scandinavia 21: 179-186.

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