LIFE HISTORIES OF NORTH AMERICAN DIVING BIRDS. 161 
The habit possessed by the black guillemot of dabbling with its bill at the 
water may have arisen in attempts to obtain food or to sip the water, but it 
has apparently degenerated into a nervous trick devoid of useful purpose, like 
the tail wagging of pipits and other birds. When disturbed by the approach 
of a boat, black guillemots often dab frequently at the water as if in nervous 
trepidation before taking flight. In rising from the water the feet are used 
as an aid, and strike back the water one after the other alternately. Black 
guillemots often chase one another in play or in passion, and make the water 
boil as they dodge in and out above and below the surface with much flapping 
of wings and spreading of tails as they thrust with their pointed bills. 
Winter—As soon as the young are able to fly, the black guillemots 
desert their breeding grounds and frequent during the winter the 
rocky shores of the north Atlantic coasts from Greenland to Long 
Island, though they are rare south of Cape Cod. They are very shy 
at this season and are usually scattered -about in small parties or 
pairs, playing in the surf off the rocky beaches or even well out at sea. 
DISTRIBUTION. 
Breeding range.—Coasts of northeastern North America and north- 
western Europe. From Maine (Matinicus Rock, eastward), New 
Brunswick (Grand Manan), and Nova Scotia (Seal Island) north 
to Labrador and southern Greenland (Holsteinborg, probably rarely 
to Disco Bay). Also from Iceland, the Faroe Islands, Orkneys, Shet- 
lands, and some of the Hebrides, northern Scotland, Ireland, and 
Wales (formerly) east to Scandinavia and the White Sea. South 
to Denmark, 
Winter range—Slightly south of its summer home. Many remain 
as far north as southwestern Greenland (Ivigtut) and few pass 
south of Massachusetts. There is one record for Connecticut, one 
definite and several indefinite records from ‘Long Island, and it has 
been supposed to occur on the Delaware River several times, but 
there is apparently but one recent definite record. It is also said 
to have been taken in Lancaster and Perry Counties, Pennsylvania, 
and once on Lake Ontario, New York. A bird taken at Toronto, 
Ontario, may be mandti. In Europe as. far north as Norway and 
south rarely to northern France. 
Spring migration—Birds wintering on the Massachusetts coast 
pass northward in April (April 11 to 19); occasionally individuals 
linger till May. 
Fall migration.—Fall migrants arrive on the Massachusetts coast 
early in November (November 5); rarely as early as September. 
Egg dates—Maine: 25 records, June 12 to July 16; 18 records, 
June 18 to 80. Bay of Fundy and Nova Scotia: 25 records, June 11 
to July 6; 13 records, June 20 to 28. Gulf of St. TDuyrenea: 18 
records, June 8 to July 15; 7 records, June 15 to 25. Great Britain: 
11 records, May 23 to June 17; 6 records, June 5 to 11. Labrador, 
east coast: 7 records, July 1 to August 2; 4 records, July 12 to 17. 
