I often wonder how it is that Budgerigars are not being constantly taken by Birds of Prey. They are noisy, often travel in large groups, and surely colourful enough to be spotted from high above. I have observed two possible reasons why they aren't taken more often (as I know they are taken at times). The first is the "lookout" bird. This isn't necessarily a Budgerigar, but I have seen at least one "lookout Budgie sentry" sitting propped on a nearby tree if others are drinking from a puddle. The second observation is that even though they appear very colourful, they have quite dull wings on the skyward side, and they must be well camouflaged in the trees when they are on the outside of the tree (have heard a lot of budgies inside trees lately).
The sentry in a nearby tree