Wing and Tail Molt of the Sparrow Hawk

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Abstract
The molt sequences of remiges and rectrices were determined in 13 captive Sparrow Hawks. On the average primaries dropped in the sequence 4[long dash]5[long dash]6[long dash]3[long dash]7[long dash]2[long dash]8[long dash]9[long dash]10/1, secondaries in the sequence 5[long dash]6[long dash]7[long dash]8[long dash]4[long dash]9[long dash]3/10[long dash]11[long dash]1[long dash]2, and rectrices in the sequence 1[long dash]2[long dash]3[long dash]6[long dash]4[long dash]5. There was substantial variability in the order of molt between individuals and between successive molts in a given individual. The most common variation involved the order of dropping of the first primary with relation to the 9th and 10th. One female began molting the primaries of the left wing with the 5th instead of the 4th feather in 2 consecutive molts. One male had only 5 pairs of rectrices instead of the normal 6 pairs. There was no definite relationship between dropping of the primaries, secondaries, and rectrices. Molt of the primaries and secondaries generally began less than a week apart, and rectrices all molted during the molt of the remiges. Corresponding feathers of right and left sides fell out normally within 3 days of each other. The molt of remiges extended through the period of general body molt. The molt sequence of the primaries of the Sparrow Hawk resembles closely that of the Kestrel. Both species show considerable variability in the molting sequence of primaries 1, 9, and 10. The Peregrine Falcon differs from the kestrels in that primary 1 regularly molts before primary 9. Use of molt sequences in determining interspecific relationships among falcons must be based on large samples to define the limits of variability in each species.