Bill (or culmen) length - the straight line distance from the bill's 

 tip to where it ends at the skin or feathers of the forehead (Fig. 2). 

 Some birds, e.g., cormorants, have bare skin where the bill reaches 

 the forehead. 



Figure 2. Measuring bill or culmen length. 



EXPOSED CUUA^EKJ LeMff-TH 



! 1 



Tarsus (plural - tarsi) length - the length of that bone (tarso- 

 metatarsus) connected to the bird's foot, from the outer edge of one 

 joint (A) to the outer edge of the other (B) in Figure 3. 



Toe length - the length of a straightened toe, from the tip (C) to 

 the knuckle (B), as in Figure 3. The key will state whether to measure 

 the inner, outer, or middle toe, or maybe just the longest toe. It 

 should also state whether to include the nail in the measurement. 



Figure 3. Measuring tarsus and toe length, 



TARSUS Le KIGTH A<- B 

 TOE LEMG.TH 8^ ^ 



OUTSIDE 



