70 



SWANS 



breast bone and emerges through a separate opening. In the Whistling Swan this 

 extra loop is missing and the entrance and exit of the windpipe are through the 

 same opening in the breast bone. The development of the windpipe within the 

 breast bones is progressive with age; in young birds of the first autumn the wind- 

 pipe barely enters the breast bone, but as the vertical loop in the Trumpeter 

 develops more rapidly than the horizontal loop, this method of identification is of 

 particular value in the case of juveniles. The Mute Swan is distinguished by its 

 red bill, with black knob or "berry" at the base of the upper mandible. 



FIELD MARKS 



ADULTS. ON THE WATER. The appearance of a swan on the water is too well 

 known to need comment. Swans are exceptionally fast swimmers. The Whistling 



Swan, though smaller than the Trumpeter, cannot 

 with assurance be distinguished in life from that 

 species except by the voice; the extreme rarity of 

 the Trumpeter, however, precludes probability of 

 confusion. On the water the Whistler and Trumpeter 

 carry the neck erect and the bill horizontal, whereas 

 the Mute Swan arches the neck gracefully with the 

 bill inclined downwards. The feathers of the wings 

 of all swans are capable of being raised, arch-fashion, 

 over the back. 



IN FLIGHT. The swan is easily recognized in flight by its very large, snow- 

 white form, with long triangular, slow-moving wings, white to the tips; the thin 

 outstretched neck, appearing like a mere line with a black point at the end, 

 occupies more than half the length. The 

 large black feet show distinctly behind 

 the body, but do not extend beyond the 

 tail. These swans pitch in to the water 

 gracefully without a splash and with- 

 out extending the feet in front as do 

 geese and ducks. When rising from the 

 water these large birds must face the 

 wind and they patter along the surface 

 for 15 or 20 feet before clearing a quick 

 get-away for so heavy a bird. In migra- 

 tion they fly in small V-shaped flocks, 

 and flock after flock follows in rapid suc- 

 cession. About their feeding grounds they move in curving lines or irregular forma- 

 tion. They fly faster than any of the ducks or geese. 



VOICE. The voice is positive identification, but as swans are usually silent on 

 the water this means of field identification is available only when the birds are 

 in flight. The notes of the Whistling Swan are varied, loud and striking at times, 

 and again soft trumpetings, like musical laughter; wow-woiv-ou, heavily accented 

 on the middle note; long whoops, or clucking sounds; repeated who-who's; a high 

 flageolet-like note; varied murmurings from high to low. The note of the Trum- 

 peter is of horn-like quality, very low in key but possessing extraordinary resonance; 

 a clear, low, almost groaning, trumpet-like call. 



