12-15 



Scaup (Aythya spp.) were by far the most abundant species 

 sighted. For the five year study period these birds averaged 35% of all 

 sightings. For the month of March they averaged 80% of all birds ob- 

 served. Total yearly scaup sightings ranged from 6400 to 19,600 (Appen- 

 dix Table 12-2) . The black duck {Anas rubripes) was the second most 

 abundant species, averaging 14% of all sightings. The five waterfowl 

 species under consideration (Table 12-1) accounted for 50% of all sightings 

 during the five year period. 



Herring gulls [Larus argentatus) were the third most abundant 

 species and the most abundant gull. Numbers sighted averaged over 4000 

 per year. Together with the ring-billed gull, black-backed gull and 

 Bonaparte's gull they accounted for 26% of all bird sightings. 



The sanderling {Crocethia alba) was the most abundant species 

 of shorebird present; sightings averaged almost 800 per year. Other 

 species present in large numbers included semipalmated sandpipers 

 {Calidris pusillus) , black-bellied plovers (Squatarola squatarola) and 

 dunlins {Calidris alpina) . Shorebirds were the least numerous of the 

 three groups (waterfowl, gulls, shorebirds) averaging only 4% of the 

 total sightings per year. However, during the months of May through 

 August, shorebirds sightings represented 28% of the total. 



For the four years of 1972, 1973, 1974 and 1976 the most 

 numerous species observed in New Haven Harbor was the scaup, followed by 

 the black duck and herring gull (Appendix Table 12-2). In 1975, however, 

 black gulls were fourth after scaup, herring gulls and ring-billed gull 

 {Larus delawarensis) . For the 10 months of 1911 , herring gulls were the 

 most abundant, followed by sanderlings, scaup and ring-billed gulls. 



The 1975 change in rankings in which two species of gulls 

 moved up is probably due to the general New England-wide increase in 

 gull numbers discussed belov\?. Although black ducks did drop in ranking in 

 1975, their numbers were higher than in 1973 or 1974. The major reason 

 for the ranking difference in 1977 was the absence of sampling during 

 the late fall migration period when scaup and black duck numbers in- 

 crease. 



