Black-faced Cuckoo-shrike - Coracina novaehollandiae
In flight, the Black-faced Cuckoo-shrike appears rather lazy, as it gives a few flaps of its wings, then glides with them by its side for a second or two; during this glide, the bird loses elevation until it flaps again, giving the flight is characteristic undulating pattern. Black-faced Cuckoo-shrikes sometimes form mobile flocks of dozens of birds, each flying in this manner but not synchronised with the other birds. Foraging Black-faced Cuckoo-shrikes may hover in the wind, plucking invertebrates from the foliage of trees and shrubs without alighting.
(Text Source: BirdLife Australia)