204 NYROCA NYROCA 



consists, he says, in a sudden jerking back of the head on the part of the male, but 

 the complete throw-back of the head on to the back, which is typical of the Po- 

 chards, is never performed. Gerald Legge (in a letter to Millais, 1913) thus de- 

 scribes it: "The throw-back of the head is very quick but I am sure that, although 

 the head goes far back, the bill is never more than perpendicular. The drakes swim 

 slowly around the duck, keeping up a very low chatter, very like, but very much 

 gentler than, the ordinary chatter of the Mallard drake. Every now and then a male 

 straightens out his head and neck along the water, then sometimes raises it sud- 

 denly to its full extent, and makes that curious wheezing cry, which is very like that 

 of the Common Pochard. . . . The male does not always straighten up after flatten- 

 ing himself on the water, but when he does he always makes the 'wheeze.' He also 

 raises his head and neck slightly two or three times in quick succession, at the same 

 time swelling out his neck and wheezing. The throw-back of the head takes place 

 frequently, and is by far the most noticeable part of the display." Millais adds that 

 when the male lays out his head and neck along the water the pupil contracts so that 

 the white of the irides is very brilliant. During courtship the male often sits high on 

 the water and moves about with the tail much elevated, so much so that the white 

 patch of the under tail-coverts becomes very conspicuous. It would be interesting 

 if we knew the exact mechanism by which diving ducks regulate their buoyancy. 

 That they can sit much higher when resting or during courtship, than when alarmed 

 or feeding, is well known. 



The nesting season is moderately late, the month of June being the normal breed- 

 ing period throughout most of the range. This is true of central and eastern Europe, 

 Morocco, Algeria, and central Asia. In Germany a few breed in late May (Nau- 

 mann, 1896-1905; Hartert, 1892; Bau, Blasius, Reichenow, and Schalow, 1877) and 

 the earliest in Poland was May 20 (Katin, 1912). According to Irby (in Dresser, 

 1871-81) nests were found on the marismas of the lower Guadalquivir, southern 

 Spain, as early as the end of April. In the Danube Valley nests were taken after the 

 middle of May (Seebohm, 1885) and in Kashmir some of these birds are said to nest 

 as early as the end of April (Baker, 1921). 



The nest itself is usually built close to the edge of the water or even over the same ; 

 sometimes it is almost, if not actually, floating. The materials used are the dry 

 stalks of grasses, leaves of sedges and rushes, dry sticks, meadow grasses and oc- 

 casionally a little moss. Several observers (Naumann, 1896-1905; Hume and Mar- 

 shall, 1879; Baker, 1921) have noticed that the inside is carefully lined with much 

 finer material, a habit which may be characteristic of the species. The nest is usually 

 well hidden by plants whose ends cross over it. Some are so constructed that they 

 can be approached only from the water side. An occasional nest has been found two 

 or three feet above the ground in a bush (Taczanowski, in Dresser, 1871-81). 



The ordinary clutch varies from six to twelve, averaging about eight or nine. 



