They have a membranous frill that connects each row of spines down the length of the dragon's body allowing undulating flight through the air.
The underwing has a black and white pattern which is visible during the undulating flight.
This bird has a courtship display in which a pair fly above the trees in an undulating flight, calling constantly.
This is a small orange-brown bird with a long tail and an undulating flight.
Some of the species also bear a superficial resemblance to cuckoos, and have a similar undulating flight.
Its undulating flight is rapid and silent.
Small flocks, usually consisting of 3-12 birds, move through the forest with an undulating flight, rarely travelling more than 100 m at a time.
Most species have at least partially metallic patterns coloration and are diurnal, sometimes swarming around the tips of branches with an undulating flight.
It has a characteristic rattling-whinnying call and an undulating flight.
It is diurnal and usually swarms around the tips of branches with undulating flights.