Imping - A Chance for Feather Damage
The word "imping" comes from falconry terminology and describes a centuries-old method of inserting new flight feathers in a hunting bird. Imping of broken feathers was already practised by falconers in antiquity by connecting the quill of the damaged feather and that of a similar intact feather, which came from a moult of the bird, with an angular steel needle, the imping needle. Additionally, the metal piece was treated with acid (lemon juice) to achieve increased stability through rapid rust formation. Nowadays, elastic fibreglass rods, carbon rods or the quills of other feathers as well as fast-hardening super glue are used. This work requires routine and utmost care, as the replaced feather must be fitted exactly into the assembly without gluing the neighbouring feathers.
In swifts, this method has probably not been performed before, and certainly not to the extent now practised. While imping of swifts began at the Frankfurt Swift Clinic in 1997 with the replacement of individual defective flight feathers, it is now possible, in exceptional cases when indicated, to replace almost the entire damaged large plumage of a swift. Up to 15 primaries and secondaries per wing as well as a maximum of ten tail feathers can be replaced. It is also possible and necessary to imp the coverts of the primaries if they are bent or broken, as they are important for the integrity and stability of the primary.
Imping supplies:
For imping defective primaries and tail feathers, commercially available carbon rods (diameter 0.5-1.8 mm) and fibreglass fishing rod tips (diameter 15/5-35/5 mm) are used as imping needles, a claw scissors or small anatomical scissors for cutting the feathers, cyanoacrylate ("UHU" brand super glue gel) for permanent connection of feather quill and imping needle. Commercially available sandpaper (grit 180, 240) is used to file the imping needles to size.
The feather material needed for imping comes from non-flightworthy old and young swifts with intact, fully developed large plumage that were either delivered dead, died in the clinic, or had to be euthanised. If possible, a swift should only be imped with feather material from a bird of the same age class, adult or juvenile, as there are differences in the size and length of the large plumage. If, for example, a young swift is imped with the flight feathers of an adult bird, there are length differences of 10-12 mm in the primaries and width differences of 1-2 mm in the feather vanes, and the proportions of the wing shift. The tail feathers are 6-8 mm longer than those of the juvenile swift. It cannot be verified what effects this has on flight style and flight ability. Therefore, it seems advisable to stay as close as possible to natural conditions.
Removing the feathers from the donor:
The feathers of the "organ donor" are accurately cut off one by one. It is advisable to number the cut feathers to avoid confusing them later, and especially to mark the distance from the feather base to the cut point, so that the same markings can be applied to the living bird and the new flight feather will "fit" later.
Preparing feathers and patient:
First, a feather set is prepared in elaborate detailed work. Small carbon or fibreglass pieces are filed to size and fitted into the feather quills. Only when all needed feathers are prepared is the affected swift anaesthetised. Without general anaesthesia, imping is usually not feasible in swifts, as these birds react extremely sensitively and with most vehement defence to any manipulation of their wings. However, they must lie absolutely still when inserting new feathers, otherwise an exact reconstruction of the wing is not possible. In exceptional cases (calm bird, only a maximum of 1-3 primaries or some tail feathers to imp), the operation can also succeed without anaesthesia, provided the performing veterinarian/falconer is experienced and familiar with the method.
Imping:
The defective feathers of the swift to be imped are carefully cut off one by one with sharp scissors at exactly the same point as on the dead "donor", taking care not to damage the overlying coverts. The subsequent fitting and gluing of the prepared "new" feathers is delicate fine work that requires skill and experience. Imping of a swift should only be performed by a falconer or veterinarian who has learned this method and has applied it many times. In swifts, the tolerance range regarding imping errors is extremely narrow. Even minor misalignments or inaccuracies can lead to limited flight ability; fitness for release would then no longer be given, as perfect flight ability is essential for the swift to survive in the wild.
Advantages of imping:
The greatest advantage of imping is that the affected swift can be released back into the wild just a few days after the procedure under general anaesthesia, in which the defective feathers were imped. Especially for breeding or feeding adult swifts, this can be of crucial importance for the survival of the brood. The pulling of damaged feathers practised in earlier times, on the other hand, carries a high risk of injury, and even if new flight feathers should regrow without complications, at least 8-10 weeks pass before a possible start. Such operations, however, are to be considered exceptions and by no means a panacea against avoidable feather damage. The prevention of nutrition- and husbandry-related feather defects must always and absolutely be the priority. Feather renewal through imping in swifts remains an "ultima ratio".
Feather renewals are extremely elaborate: Preparing
a new feather set takes approximately 6 hours, the imping itself 1-3 hours depending
on scope. But it is certainly a wonderful moment when
such a "completely renewed" swift, who would have been condemned to death without imping, rises powerfully into the sky - and a final tribute to the one who had less luck than he, but through his intact feathers enabled him to live in freedom.
