16 



KEY TO BIRD KEYS 



If wings are: use: 



1. very large, > 470 mm long Key A. 



2. large, 338-467 mm long Key B. 



3. moderate to small, 162-337 mm long Key C. 



4. small, <161 mm long Key D. 



KEY A. SIZE VERY LARGE, WING >470 mm. 



1 Primary 10 decidedly longest feather when wing folded completely in 

 natural position; primaries not cut out on either web (Fig. 10); four 

 toes connected by incomplete webs (Plate 37-1,2) OR if fully webbed 

 then only three toes connected (Plates 35, 36-1,2,3) and scales on 

 fore-edge of tarsi scutellate (Fig. 13). 2 



1' Primary 10 not longest wing feather or equal in length to primary 

 9; primaries 10-8 may be cut out on one or both webs (Fig. 10); 

 four toes connected by complete webs (Plate 36-4) OR if three toes 

 webbed then scales on tarsi reticulate (Fig. 13). 7 



2 Wing >600 mm; webbing incomplete, restricted to basal third of toes; 

 nail on middle toes flared and comb- like (Fig. 17). 3 



2' Wing <580 mm; three longest toes joined by full webs; no toenails 



comb-like. 5 



Figure 17. A booby's or frigatebird's comb-like 

 toenail; (about twice natural size). 



