 The calami of the flight feathers are protected by a layer of non @-@ flight feathers called covert feathers or tectrices ( singluar tectrix ) , at least one layer of them both above and beneath the flight feathers of the wings as well as above and below the rectrices of the tail . These feathers may vary widely in size — in fact , the upper tail tectrices of the male peafowl , rather than its rectrices , are what constitute its elaborate and colorful " train " . 
