Abstract

The objective of this study was to evaluate if surgical removal of broken feathers was an efficient method to induce growth of new flight feathers as part of the rehabilitation process of raptors with damaged plumage. Primaries, secondaries, and rectrices (four of each) were removed under general anesthesia from 10 American kestrels (Falco sparverius) using two different techniques: with and without filling the follicle with bismuth subnitrate (OrbeSeal^®, Pfizer Animal Health, Kirkland, QC, Canada) to prevent it from closing up. Birds were kept in large aviaries under natural daylight and outdoor temperatures. Growth of new feathers was assessed weekly for 4 months in regard to the rate and quality. Results were significantly different between the types of feathers: 100% of rectrices, 58% of secondaries, and 8% of primaries grew within the four winter months. The tail feathers began to grow between the second and the third weeks at about 2.4 mm per day, and growth was usually completed within 5 weeks. Rate, starting time, and duration of remiges growth were less predictable and varied widely among individuals. The use of OrbeSeal^® did not improve the outcome. Bleeding during extraction was associated with a poor regrowth prognosis. We conclude that plucking damaged tail feathers in kestrels can successfully decrease the duration of a rehabilitation process instead of waiting for a natural molt. However, this procedure would not be recommended for wing feathers.