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. A 'light' symmetrical wing-clip allows a bird to fly down and land safely while indoors. However, such a clip may not prevent the bird from flying when outdoors, since lift is generated in proportion to wind speed. Many escaped birds that are recovered are found to have been clipped. So, while a light clip allows downward flight indoors, it does not prevent a bird gaining lift if it should escape outdoors. Conversely, a more severe clip certainly renders a bird flightless, but it increases the risk of injury if the bird falls and hits a hard surface. In addition to the physical effects of wing-clipping, adverse behavioural effects can occur. Birds use flight as an instinctive reflex action and as their first means of escaping any threat; they take to the air to fly upwards and away from the source of the threat; their fear then dissipates. Where this behaviour is prevented by wing-clipping, this innate reflex action is denied the bird, and its fear does not subside. This may cause behavioural problems for the afflicted bird. When a bird needs to reduce its speed during flight, it employs a 'reverse thrust' action by extending its wings vertically and using the drag of its primaries as air brakes. While the reduced function of the clipped bird's primaries prevent propulsion and therefore lift, this also reduces braking abilities, so clipped birds may crash-land at higher speeds than full-winged birds. Clipped birds should not be taken outdoors unrestrained, as even clipped birds have been known to fly away when spooked outdoors. It is generally considered very important for a young bird to be allowed to fledge (learn to fly) properly, prior to any wing clipping. Breeders and owners usually