Harrier (bird) Harrier (bird) A harrier is any of the several species of diurnal hawks sometimes placed in the Circinae sub-family of the Accipitridae family of birds of prey. Harriers characteristically hunt by flying low over open ground, feeding on small mammals, reptiles, or birds. The young of the species are sometimes referred to as ring-tail harriers. They are distinctive with long wings, a long narrow tail, the slow and low flight over grasslands and skull peculiarities. The harriers are thought to have diversified with the expansion of grasslands and the emergence of C4 grasses about 6 to 8 million years ago
Singing bird box In some movements the flapping of the bird's wings and its ability to turn its head are also cam-controlled, in others not. The final cam determines the point at which the song ends, the bird folds away, the lid drops and the motor stops. The bird's beak movements are always connected to the cam controlling the air supply to the whistle: in this way the sound and beak movements are automatically synchronized. The whistle consists of a miniature organ pipe containing a close-fitting piston which can be moved up and down to give a range of notes of over an