Table 2.

Differences in body angle and swim speed in descent and ascent phases, and those in stroke duration, frequency of wing stroke and thrusts, heave at upstroke and downstroke, and maximum surges at upstroke and downstroke

BRGU (2 birds)COGU (4 birds)RAZO (4 birds)RHAU (3 birds)LIPE (2 birds)
Descent
    Body angle (deg.)-78.4±1.3 (106)-75.6±0.8 (171)-44.5±0.7 (165)-43.2±0.5 (380)-36.5±0.8 (102)
    Swim speed (m s-1)1.40±0.02 (106)1.61±0.01 (171)1.59±0.02 (164)1.06±0.01 (380)1.85±0.02 (93)
    Upstroke duration (s)0.218±0.002 (282)0.204±0.001 (468)0.188±0.001 (359)0.199±0.001 (784)0.163±0.001 (395)
    Downstroke duration (s)0.211±0.002 (282)0.180±0.001 (468)0.172±0.001 (359)0.194±0.001 (784)0.132±0.001 (395)
    Frequency of wing strokes (n s-1)2.34±0.01 (282)2.61±0.01 (468)2.77±0.01 (359)2.57±0.01 (784)3.44±0.02 (395)
    Frequency of thrusts (n s-1)4.61±0.04 (282)4.00±0.07 (468)4.42±0.07 (359)5.07±0.02 (784)6.87±0.04 (395)
    Min. heave at upstroke (m s-2)-5.94±0.08 (282)-4.83±0.03 (468)-5.55±0.04 (359)-4.28±0.02 (784)-4.48±0.04 (395)
    Max. heave at downstroke (m s-2)7.91±0.12 (282)7.44±0.04 (468)8.70±0.06 (359)6.93±0.05 (784)4.94±0.05 (395)
    Max. surge at upstroke (m s-2)1.83±0.07 (282)0.33±0.05 (468)0.42±0.05 (359)1.45±0.03 (784)2.36±0.03 (395)
    Max. surge at downstroke (m s-2)6.08±0.08 (282)7.85±0.06 (468)8.32±0.09 (359)5.32±0.05 (784)1.97±0.03 (395)
Ascent
    Body angle (deg.)56.6±1.6 (112)56.6±1.1 (172)45.5±0.9 (153)26.3±0.5 (350)50.9±2.0 (85)
    Swim speed (m s-1)1.56±0.04 (103)1.78±0.02 (172)1.63±0.03 (150)1.79±0.02 (333)1.91±0.02 (73)
  • Means ± s.e.m. are shown, with sample sizes in parentheses. Sample unit is 1-s interval for body angle and swim speed and strokes for others.

    BRGU, Brünnich's guillemot; COGU, common guillemot; RHAU, rhinoceros auklet; RAZO, razorbill; LIPE, little penguin.