WING AREA and TOTAL WEIGHT - BIRDS 



If all birds were dimensionally similar, the wirtg area divided by 

 the two - thirds power of the total weight would be constant 

 The plot shows this to be roughly the cose for certain 

 orders and families. Variations between families can, 

 however, be very great Ducks, for example, fall in a region 

 for which "unit wing area " averages about 7.5, for falcons 

 and allied genera, "unit wing area " averages about 20 

 Although precise data are not available, it is probable that 

 ducks compensate for their relatively tower win^ area 

 with a correspondingly higher wing beat rate 

 "unit wing area " is the constant in the equation 

 A = cM^" . The lines in the plot correspond to the 

 given values for c. 



