110 BULLETIN 113, UNITED STATES NATIONAL MUSEUM. 



gleaned when the vessel is discharged. In the harbors of populous 

 cities there is always food to be found floating on the water, particu- 

 larly in the neighborhood of fish wharves and at the mouths of 

 sewers. The service to sanitation in these places is of great value. 

 At Boston large quantities of sewage are poured out into the harbor 

 at Moon Island just after the tide begins to ebb. Gulls collect from 

 all sides in anticipation of this event and rest on the water offshore 

 or fly to and fro until the sewer gates are opened; Then, heedless 

 of the onlookers, they fly in crowded ranks close to the unsavory 

 fountain head and dip gracefully for the titbits to be found there. 

 It is an interesting fact and an indication of considerable intelligence 

 that gulls, although very wary in regions where shooting is carried 

 on, become entirely tame and confiding where this is forbidden, as is 

 the case in harbors and bird reservations. 



At times, however, but not often, the herring gull resorts to the 

 tactics of the tern, and captures small live fish by plunging headlong 

 into the water. Occasionally this plunge is made from a height of 

 15 or 20 feet, and the bird disappears below the surface, soon to 

 emerge with its prey. Sometimes a whole flock can be seen engaged 

 in this occupation as they follow a school of fish. At other times, 

 the plunge with partly open wings is made from only a few feet 

 above the surface, and the bird is only partially immersed. I have 

 seen the members of a flock of herring gulls riding in shallow water 

 fly up a few feet into the air in order to obtain impetus for a short 

 dive below the surface for some prey. Knight (1908) describes the 

 plunging of these gulls from the air and says : 



They flew about the open water in circles * * * and as their keen 

 eyes detected some fish at this upper portion of their range they plunged with 

 force into the water, quickly rising to the surface as a usual thing, though 

 on at least one occasion a bird was out of sight so long that I had grave 

 fears that it would .be carried under the ice by the swift current, but it 

 finally emerged at the edge of the ice and took, wing with an unsually large 

 tomcod. • Nearly every plunge seemed to be successful, the birds swallowing 

 the smaller fish before taking wing, but when a large fish was captured they 

 would fly to the ice near by and after batting the fish from side to side on 

 the ice would finally swallow it. 



When herring are caught in pounds and traps there are some 

 dead or dying fish that are c\ otured by the gulls, which have, there- 

 fore, been accused of damaging the fishery. It is probable that their 

 work here is more properly that of scavengers in keeping the traps 

 free from dead fish, and, therefore, beneficial. 



The sand beaches are at times covered with stranded fish, small 

 and large; sand launces, herring, cod, hake, haddock, pollock, dog- 

 fish, and skates are often thrown up or cast themselves ashore, pur- 

 sued and pursuers alike. Their dead bodies would soon become 

 intolerable were it not for the greediness of the gulls who come from 



