Ancient murrelet in beating flight inside water

　The thickset spindle‐shaped body and the slender short wing are their characteristics, though they are not so a penguin. Inside water, the burdensome primaries are folded and kept backward, and only the secondaries play the leading role. To give the sufficient structural intensity for wing, the number of the secondaries is rich. Since there exists the buoyancy comparable to the gravity inside water, they flap the wing with zero angle of attack and produce only the thrust, or flap the wing with nagative(positive) angle of attack and produce the negative (positive) lift to the diving (the rising). Since the density of water is larger order of 1000 compared with that of air, the amplitude and the velocity of the flapping may be small by that order. The webbed feet located rearward are not used to the propulsion but only to the steerage.
(Prod. Aug. 2002, full‐scale, No.2)