 In some species , for example , either remiges or rectrices make a sound during flight . These sounds are most often associated with courtship or territorial displays . The outer primaries of male broad @-@ tailed hummingbirds produce a distinctive high @-@ pitched trill , both in direct flight and in power @-@ dives during courtship displays ; this trill is diminished when the outer primaries are worn , and absent when those feathers have been moulted . During the northern lapwing 's zigzagging display flight , the bird 's outer primaries produce a humming sound . The outer primaries of the male American woodcock are shorter and slightly narrower than those of the female , and are likely the source of the whistling and twittering sounds made during his courtship display flights . Male club @-@ winged manakins use modified secondaries to make a clear trilling courtship call . A curve @-@ tipped secondary on each wing is dragged against an adjacent ridged secondary at high speeds ( as many as 110 times per second — slightly faster than a hummingbird 's wingbeat ) to create a stridulation much like that produced by some insects . Both Wilson 's and common snipe have modified outer tail feathers which make noise when they are spread during the birds ' roller coaster display flights ; as the bird dives , wind flows through the modified feathers and creates a series of rising and falling notes , which is known as " winnowing " . Differences between the sounds produced by these two former conspecific subspecies — and the fact that the outer two pairs of rectrices in Wilson 's snipe are modified , while only the single outermost pair are modified in common snipe — were among the characteristics used to justify their splitting into two distinct and separate species . 
