Aix galericulata. Pugnacity. Jan. 3, 1909. I have placed several ducks, Mallard, Pintail, and Green-winged Teal, in the yard previously occupied by the pair of Mandarin Ducks exclusively. Their latter show great pugnacity, attacking even the Mallard. They run at the intruders with open mouth, seizing them by the feathers of the neck or back and hanging on with great tenacity. The Green-winged Teal and the female Pintail appear afraid of them. March 18, 1909. Both the Mandarins seem to delight in chasing chasing the Green-winged Teal and the Shoveller which I have in their yard. The female's head and neck resemble that of a snake as she rapidly darts her head at them opening her mouth wide at the same time. While chasing the birds the drake often makes a rather pleasant sweet clucking. July 18, 1909. The female Mandarin is not in fresh plumage yet. The male however is in the eclipse plumage and greatly re- sembles the female except that his plumage is fresh and brighter, this bill is about the color of the females; at other times it is reddish.