Table 3.

The calculated drag coefficient for each stage of the paddling cycle of the great cormorant and the resulting average drag per cycle

BirdMass (kg)Length (m)Re×106RpRCd,glideCd,recoveryCd,strokeDrag cycle-1
1 1.99 0.74 1.04 1.22±0.16 0.62±0.21 0.176±0.145 0.030±0.353 0.339±0.041 4.3±0.14 
2 2.30 0.82 1.41 0.73±0.20 0.55±0.27 0.101±0.031 0.476±0.230 0.711±0.233 10.6±2.05 
3 1.89 0.73 0.94 1.04 1.26 0.180 0.565 0.394 5.2 
4 2.10 0.79 1.32 1.01±0.20 0.50±0.13 0.120±0.043 0.201±0.097 0.556±0.418 7.4±4.35 
5 2.40 0.77 1.24 0.80±0.15 0.49±0.16 0.124±0.026 0.183±0.103 0.480±0.164 6.0±2.02 
6 2.18 0.77 1.31 0.62±0.12 0.43±0.04 0.091±0.017 0.122±0.104 0.411±0.135 4.7±1.06 
7 2.00 0.76 1.11 1.31±0.19 0.80±0.23 0.166±0.087 0.189±0.085 0.287±0.211 4.07±2.90 
8 1.48 0.72 1.00 1.22±1.24 0.82±0.22 0.180±0.041 0.423±0.256 0.373±0.104 3.2±0.55 
9 1.80 0.71 0.92 1.16±0.32 0.74±0.58 0.171±0.025 0.343±0.289 0.325±0.083 3.5±0.9 
10 1.90 0.75 1.21 0.79±0.02 0.57±0.03 0.119±0.061 0.194±0.243 0.441±0.007 5.6±1.00 
Mean ± S.D. 2.004±0.263 0.76±0.03 1.12±0.172 0.99±0.242 0.68±0.246 0.143±0.035 0.273±0.171 0.432±0.126 5.5±2.16 
BirdMass (kg)Length (m)Re×106RpRCd,glideCd,recoveryCd,strokeDrag cycle-1
1 1.99 0.74 1.04 1.22±0.16 0.62±0.21 0.176±0.145 0.030±0.353 0.339±0.041 4.3±0.14 
2 2.30 0.82 1.41 0.73±0.20 0.55±0.27 0.101±0.031 0.476±0.230 0.711±0.233 10.6±2.05 
3 1.89 0.73 0.94 1.04 1.26 0.180 0.565 0.394 5.2 
4 2.10 0.79 1.32 1.01±0.20 0.50±0.13 0.120±0.043 0.201±0.097 0.556±0.418 7.4±4.35 
5 2.40 0.77 1.24 0.80±0.15 0.49±0.16 0.124±0.026 0.183±0.103 0.480±0.164 6.0±2.02 
6 2.18 0.77 1.31 0.62±0.12 0.43±0.04 0.091±0.017 0.122±0.104 0.411±0.135 4.7±1.06 
7 2.00 0.76 1.11 1.31±0.19 0.80±0.23 0.166±0.087 0.189±0.085 0.287±0.211 4.07±2.90 
8 1.48 0.72 1.00 1.22±1.24 0.82±0.22 0.180±0.041 0.423±0.256 0.373±0.104 3.2±0.55 
9 1.80 0.71 0.92 1.16±0.32 0.74±0.58 0.171±0.025 0.343±0.289 0.325±0.083 3.5±0.9 
10 1.90 0.75 1.21 0.79±0.02 0.57±0.03 0.119±0.061 0.194±0.243 0.441±0.007 5.6±1.00 
Mean ± S.D. 2.004±0.263 0.76±0.03 1.12±0.172 0.99±0.242 0.68±0.246 0.143±0.035 0.273±0.171 0.432±0.126 5.5±2.16 

Cd,glide, Cd,recovery and Cd,stroke are the drag coefficients during the glide,recovery and stroke stages, respectively (see text for the description of the stages).

Also listed are the dimensions of the birds: mass used to estimate the area of the birds (V2/3) and length used in the calculation of the Reynolds number (Re) for the swimming cycle, Re=(length×U)/ν, where U is the average swimming speed for a paddling cycle. Rp and R are the energy ratios in the burst and glide model, where Rpis calculated with the recovery stage as part of the burst stage and R is calculated with the recovery stage as part of the glide stage.

Values listed are the means for each bird ± s.d. The sample size for each bird is as listed in Table 2.

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