Wing clipping

Wing clipping is the process of trimming a bird's primary flight feathers ("primaries") so that it is no longer fully flighted.

Wing clipping is usually performed by avian veterinarians, pet store employees, breeders, or the birds' owners themselves. It is generally carried out on pet birds, particularly parrots. If performed correctly, it is a painless procedure and is quite distinct from pinioning, which is carried out by amputation of the wing at the carpal joint.

Techniques for clipping the wings vary primarily in the number of feathers cut and the amount of each feather left behind. A mild clip on one wing only can impair a bird's flight greatly, as it renders the bird unbalanced in the air. This can cause injury or death to the bird if it strikes a hard surface during a fall. In most cases, it is only the primary flight feathers that are cut, and an equal number of feathers are trimmed on each wing to avoid causing the bird to become unbalanced in flight. The most common clip involves trimming the primary flight feathers below the level of the primary coverts (usually removing about half to a third of the length of the flight feather). This clip is quick and simple to do, but leaves exposed cut ends that occasionally may cause a bird to chew on the cut feathers. Another method of clipping involves cutting the flight feather above the level of the coverts, so almost the entire feather is removed. This clip does not leave any exposed cut ends, but as more of each feather is removed, fewer feathers should be cut. However, these cut feather stumps are still present and may irritate the bird, causing significant discomfort.

Where parrots have clipped primary feathers, the moulting sequence of these birds renders them vulnerable to damage of their growing blood feathers. Most parrots have 10 primary feathers, numbered 1 (innermost) to 10 (outermost). The moult starts by the bird shedding and replacing a central primary feather, usually number 6 (Glendell 2007). The sequence continues in both directions along the primaries, so the last primary feathers to be replaced are the innermost and the outermost ones numbered 1 and 10 respectively. Clipped birds therefore have their first blood feathers growing down without the normal protection of full-length feathers lying next to them. These unprotected blood feathers are vulnerable to being broken and profuse bleeding can occur. Regardless of their size, most parrots replace their feathers by a daily growth rate of 3 to 4 mm (Glendell 2007) Thus, large species such as macaws may take over a year to complete a moult, but smaller species such as cockatiels will moult within a few weeks. So, larger birds, and those with a higher wing-loading, remain vulnerable to blood feather damage for a longer period, since they are moulting almost continually.

...
Wikipedia