HARLEQUIN DUCK 377 



Although flocks are usually small they do, in winter, occasionally gather into 

 considerable bunches. W. Palmer (1899) frequently saw as many as 150 together on 

 St. Paul Island, Bering Sea, and W. L. Dawson and Bowles (1909) mention a flock 

 of five hundred on Puget Sound. 



i & v 



Association with other Species. Many naturalists have observed the inde- 

 pendent disposition of the Harlequin and its distaste for the companionship of 

 other ducks. This is true not only on the coastal haunts but also on the interior 

 breeding grounds. At times, however, they drift about in the company of Long-tails, 

 but such association is not characteristic. 



Voice. As a rule the Harlequin is a silent bird, but several different sounds have 

 been attributed to the male. The typical courtship note, which is also heard in 

 winter, is a peculiar whistle which the fishermen of Maine liken to the squeaking of 

 a mouse (Norton, 1896). Afford (1920) says the "low piping whistle" more nearly 

 resembles the call of the Sandpiper than any note he has ever heard. Bretherton 

 (1896), who observed these ducks on Kadiak Island, Alaska, describes the male's 

 cry as a "shrill whistle, descending in cadence from a high to a lower note, com- 

 mencing with two long notes and running off in a trill." An apparently different 

 spring note, consisting of a low giak or gid, is spoken of by both Faber (1822) and 

 Hantzsch (1905). 



The ordinary caU of the female is a harsh croak, but this note is modified in vari- 

 ous ways. On the breeding grounds a note sounding like ek-ek-ek-ek or gdg-gdg-gdg 

 has been heard and both Faber (1822) and Hantzsch (1905) assign the giak call to 

 the female as well as to the male. 



The trachea was first adequately figured by Alfred Newton (1859), but was earlier 

 described in Audubon's Ornithological Biography (vol. 5, p. 617, 1839). It has 

 several peculiarities and certainly shows little if any relationship to that of any 

 diving duck. There are two enlargements in the tracheal tube itself, one a moderate 

 one in the upper part followed by a constricted portion below. Then just above the 

 bifurcation is a larger swelling about half an inch in diameter, which terminates in 

 the very large, left-sided tympanum, which is remarkable in not having any of the 

 membranous windows common to all the other diving ducks except the Eiders. 

 (In the Scoters, as Newton remarks, there is nothing that can properly be called a 

 tympanum or bulla ossea.) 



Food. The diet of this duck is, of course, almost entirely of an animal nature. 

 Usually the shellfish it takes are smaU but I have seen some spiral shells from 15 to 

 20 mm. long taken from the stomach of one shot in Maine in winter. Besides niol- 

 lusks of various kinds, isopods, crustaceans, caddis-fly larvae, and the larvae of many 



