BLACK TERN ( Chlidonias niger ) 



Status . --Transient, probably rare in spring and uncommon in fall, over 

 Continental Shelf. 



Normal period of occurence . --SPRING: early to late May. FALL: early 

 July to late September. 



Records . --17 in 2 h, 2-50 km E and SE Ocean City, 23 August 1977; 1, 2 km 

 E Ocean City, 24 August 1977. 



RAZORBILL (Alca torda ) 



Status . --Uncommon winter visitant, generally ranging offshore to the 30 

 fathom contour (Fig. 32). 



Ea rliest winter record . --23 December 1972 (Stewart and Robbins (1958) 

 report a 4 December 1926 sighting.) 



Latest winter record . --25 March 1973. 



Maximum counts . --28 in 7 h, 9-39 km SE Ocean City, 16 January 1977; 53 in 

 4 h, 18-35 km ENE Ocean City, 12 Febuary 1977; 8 in 2 h, 22-28 km ESE Ocean 

 City, 25 March 1973. 



Remarks . --Occasionally, large numbers of alcids migrate southward in 

 winter to shelf waters along the eastern North American coast. The record 

 numbers of razorbills off Maryland in January - February 1977 may have been 

 associated with a mass southward movement along the New England coast reported 

 by Vickery (1977) for the winter of 1976-1977. Except for early 1977, razor- 

 bills in the northern Chesapeake Bight were solitary or in groups up to three. 

 They were seldom associated with other seabirds. Razorbills, like most alcids, 

 usually dive rather than fly away from a boat. This habit undoubtedly resulted 

 in many individuals being overlooked. On 12 February 1977, linear groups of 

 3-10 were observed on the water, perpendicular to the boat's approach. When 

 we approached to about 15 m, all birds dove at once. Razorbills generally 

 showed no interest in chum. 



44 



