During their first fall and winter, a substantial fraction of the immatures may replace both their immature tertials and tertial coverts with adult-type feathers. Thus, it is important to look closely at the middle coverts immediately anterior to the tertial coverts for indications of the trapezoidal shape, duller color, and wear that indicate immaturity. Primary coverts of many immatures have light edging on their inner webs. This type of edging does not occur on adults. Sex Determination of Adults Adult male tertials are more than 90 mm.
Tertial coverts have broad edging which is pale brown.
Middle and lesser coverts are broadly rounded and unfrayed. Adult female tertials are less than 90 mm. Pearly color generally does not occur on the outer webs. Tertial coverts have broad edging which is pale brown. Middle and lesser coverts are broadly rounded and unfrayed.