LIFE HISTORIES OF NORTH AMERICAN DIVING BIRDS. 93 



The bill of the puffin is in truth a mask, for it is large and bril- 

 liant only during the season of courtship, and is mostly cast off to be 

 replaced by a smaller, duller one for common use the rest of the 

 jear. The bill is the same in the two sexes, and, at the height of the 

 breeding season, is a brilliant scarlet with triangular patches of steel 

 blue at the bases of both mandibles ; about the middle of the upper 

 mandible, on either side, is a narrow band of white. The commissure, 

 bare of feathers, is a brilliant orange. The whole inside of the 

 mouth and tongue is a light yellow. Nor is this all, for the eyeel 

 •during the courtship season are provided with a narrow horizontal 

 horny line below, and one running diagonally back above while the 

 «dge of the eyelids is a vivid vermillion. The eyes themselves are 

 small and blue-black, and sparkle in the wonderful setting. 



After the breeding season the puffin puts aside its mask by shed- 

 ding the following pieces, according to Coues (1903) : 



1, Basal rim or collar ; 2, nasal case or saddle ; 3, mandibular case or shoe ; 

 4, 5, strips at base of mandible, one on each side ; 6, 7, subnasal strips, one on 

 ■each side ; 8, 9, prenasal strips one on each side. 



The homy appendages of the eyelids are also shed. The horny 

 molt by which the whole bill becomes smaller takes place at the same 

 time with the feather molt in August and September. The orange 

 skin at the commissure becomes pale and shrunken and the feet 

 ■change from brilliant orange red to yellow. 



Food. — The food of the puffin is almost exclusively fish and on the 

 Labrador coast the capelin seems to be their favorite. Crustacean 

 and other forms of marine life are doubtless also eaten. 



Behavior. — Puffins are as a rule unsuspicious and generally allow a 

 ■close approach. As one approaches in a steamer or other boat, the 

 «wimming bird shows its anxiety by nervously dipping its head into 

 the water from time to time. Then it is apt to show the greatest in- 

 decision as to which action to adopt — ^flight below the water or above. 

 Both actions — aerial as well as subaqueous — can be described as 

 flight, for the wings, although held somewhat differently, are as vig- 

 orously used below the water as in the air. In the former as in the 

 latter case the feet are not used but trail behind. One can easily 

 observe the beginning of the subaqueous flight, for the wings are 

 flapped out for their first stroke as the bird enters the water. Unless 

 the wind be strong against them, they have great difficulty in rising 

 from the water, and often splash along the surface for some distance 

 before they can rise above it. Many a time they give up the at- 

 tempt and rest before trying again, but often continue the flight by 

 •dipping below the surface, without a pause in the process. I have 

 often seen them emerge from a wave, fly across the trough and enter 

 the next wave without apparent change in their method of propul- 

 sion. Again I have seen them come out of the water flying, only to 



