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KEY TO MALLARD WINGS 
Sex Determination 
Reeeulane 
(a) Some vermiculated ----------------------.--------.. Male 
(b) All barred (or absent) ---------~--------------.-.- 2 
Proximal Under-wing Coverts: 
(a) Conspicuously barred ------------------------------ 3 
(b) Vermiculated ------------------------~--+----------- Male 
White Bar Anterior to Speculum: 
(a) Extends proximally at least partially over tertials-Female 
(b) Does not extend over tertials --------------------- Male 
Age Determination of Males 
Greater Tertial Coverts: 
(a) Any of the following: much frayed, faded, 
noticeably narrow and dull colored --------------- Immature 
(b) Not frayed or faded, generally broad, often 
rufous colored ------------------------------+----- 2 
Tertials: 
(a) Any of the following: "pearly" color lacking, 
much frayed at tips, much faded, erupting new 
tertial after December lst ---------------------.- Immature 
(b) Generally "pearly" colored, not frayed or faded, 
no new tertials erupting ------------------------- 3 
Primary Coverts: (Tip of inner web on four most distal coverts) 
(a) "Conspicuously" to "minutely" light edged --------- Immature 
(b) No edging present -------------------+-------------- 4 
