Fig. 1. Lateral-view video images from the sequence of a diving puffin used to generate Figs 2–4 and 5A,B. Frame numbers correspond to the numbers used in Figs 2 and 3.
Fig. 2. Dorsal (x,z plane) and lateral (x,y plane) views of a sequence of a diving puffin relative to still water. Symbols mark the positions of digitised points (see text for definitions): , Tail; , BeakBase; , Beak; , Wrist; , Tip; , DistWrist; , DistTip. Numbers in the graph correspond to frame numbers (see Fig. 1), each separated by 0.02 s. Values are means of three separate measurements, and error bars (S.E.M.) illustrate measurement error.
Fig. 3. (A) Dorsal view (x,z plane) and (B) lateral view (x,y plane) of the wing movement relative to the movement of the tail tip (Tail) and eye (Eye) respectively. Symbols mark the positions of digitised points (see text for definitions): , Tail; , BeakBase; , Beak; , Breast; , Wrist; , Tip. Numbers in the graph correspond to frame numbers (see Fig. 1), each separated by 0.02 s.
Fig. 4. Three-dimensional representation of the left wing of an Atlantic puffin (Fratercula arctica) during diving. The spheres represent the position of the tail tip (Tail) and the rods represent the line between the wrist (Wrist) and the wing tip (Tip) and between the wrist and the elbow. The motion goes from right to left (i.e. starting with the red colour and ending with the green colour). The printed version and the start image of the movie (see http://www.biologists.com/JEB/movies/jeb3799.html) shows a ventral/lateroventral view. The three-dimensional coordinates were produced according to the specifications in the Materials and methods section.
Fig. 5. Velocity () and acceleration () in the x (A) and y (B) directions of the puffin in the sequence used in Figs 2–Fig. 5 and in the x (C) and y (D) directions of a bird in a sequence showing positive acceleration in the x direction during the upstroke. The upstroke of the wrist point (Wrist) is from the start of the light grey area to the end of the dark grey area. The upstroke of the wing tip (Tip) is from the start of the dark grey area to the end of the light grey area. The values are means of the velocity and acceleration of three digitised points on the body (Beak, Eye and Breast) and error bars are ± S.E.M. (see text for definitions).
Fig. 6. Graphs showing the relationships between (A) stroke frequency and mean swimming speed, (B) stride length and mean swimming speed and (C) stroke frequency and mean acceleration. The different symbols represent six different individuals. The regression coefficients in A, B and C are significantly greater than zero.
, Tail; 
, BeakBase; 
, Beak; 
, Wrist; 
, Tip; 
, DistWrist; 
, DistTip. Numbers in the graph correspond to frame numbers (see 
, Breast; 
) and acceleration (