Vol.1945 62]] GROSS,Status ofGreat Black-backed Gull 241 97. Melospiza georgiana,SWAMP S•,Am•OW.--Fairly common summer resident. St. Anthony, May 28 to September 19. 98. Plectrophenaxnivalis nivalis, EAST•tN SNOWBtrNTXNG.--Common in migration. Occasionalwinter straggler. St. Anthony, March 27 to May 2; October 13 to November 11. Cape Batfid, October 10, 1943. LABRADOR NoTeS OF INTeReST 1. Ga•a $tellata,R•D-THROAT•D LOON.--lkigolet, September24, 1940 (spedmen). 2. Fulmarusglacialis glacialis, ATLANTIC FULMAR.--Batteau, September 21, 1940. 3. Histrionicushistrionicus histrionicus, EASTERN Iff•m,•Qtr•N Dtmx.•Square Island, July, 1940. Stuffed bird recently killed offered to me for sale. 4. Melanltta fusca deglandl,WHIT•-WXNGB• ScoT•R.--Rigolet, September 21, 1940 (•fty). 5. Melanitta perspicillata, Strm• ScoT•.--Lake Melville, September 15, 1940; September 21, 1940 (2000). 6. Mergus serrator, I•-B•AST• M•ANS•.--Lake Melville, September 16, 1940 (adults with young). 7. Arenaria interpres,R•or•¾ TtmNSTON•.--Oready, August 23, 1936; Seal Islands, September 12, 1940; Barteau, September 21, 1940. 8. Eroliafuscicollis, WmT•-•tnm,• SaNm'n,•R.--Indian Harbor, abundant summer resident. July 22, 1935, adults seen with young birds (I can find no record of the bird's breeding in Labrador). 9. Crocethiaalba, SAN•RLIN•.--Brador Bay, September 23, 1936 (Bttrge). 10. Hirundo rustica erythrogaster,B•mN SwALLOW.--Indian Harbor. One record, August 23, 1935. 11. Loxia Ieucopteraleucoptera, Wm•-WIN• C•osssmL.--Indian Harbor, August 7, 1935. Washington,D.C. THE PRESENT STATUS OF THE GREAT BLACK-BACKED GULL ON THE COAST OF MAINE 1 BY ALFRED O. GROSS Plates 12-15 Sx•c•the beginningof the presentcentury great changes have taken place in the populations of the sea birds inhabiting the Maine coast. The unprecedentedincrease brought about by protectionand other contributing factors has involved seriouscompetition among the birds, which is requiring many readjustments. For example, islands which 25 years ago were inhabited by thriving coloniesof terns have sincebeen completely taken over by Herring Gulls and today are •ow being encroachedupon by the Black-backed Gulls. Not only have theseincreases affected the interrelationsof the birds Contribution no. 13, Bowdoin Scientific Station, Kent Island, Bay of Fundy, New Brunswick, anada. 242 C;Ross,Status ofGreat Black-backed Gull but some of them concern the direct interests of man. For instance, the Double-crestedCormorant was completelyextirpated as a breeding bird on our coastin 1900, but by 1930 it had again establisheditself. Today it has extendedits range as far as the coast of Massachusetts and has increased its numbers to such an extent that demands are being made, chiefly by representativesof the fishing industry, that effective control measuresbe instituted. Cf. Gross (1943 and 1944). The American Eider, which was reduced to the low ebb of two nest- ing birds in 1907, has also made a remarkable recovery and today is well establishedas a nesting spedes as far southwestas Mark Island in CascoBay. Cf. Gross (1944a). The Herring Gull, which was threatenedwith exterminationas a nesting specieson the Maine coast in 1900, today has becomeso abundant that the U.S. Fish and Wildlife Service has found it neces- sary to take active steps towards its control. Similar changesin populationsare likewisetrue in the caseof other species. During the past four yearsI have had an opportunity,while serving with the U.S. Fish and Wildlife Service as a collaborator from 1941- 1943 and as Biologist in 1944, to observe and record the recent changesthat are taking placein the sea-birdcolonies along the Maine coast.• Thesetrips were taken eachyear from about May 20 to June 20 at the height of the nestingseason. All of the important Herring Gull coloniesbetween the Isles of Shoals at the New Hampshire- Maine state boundaryto the Bay of Fundy werevisited for the purpose of gull control. This paperwill dealprimarily with the presentstatus of the Great Black-backedGull (Larus marinus). The Great Black-backedGull is a recent addition to the nesting birds of the Maine coast although certain publicationsin the past have implied that it nestedin this region. The vaguestatement of J. J. Audubon(1835) that: "None breedsouth of the easternextremity of Maine" has never been considered as a definite record for the state. G. A. Boardman (1862) in his 'Catalogueof the Birds found in the vidnity of Calais, Maine, and about the Bay of Fundy,' wrote as follows: "Resident. Not plenty. A few breed about the islands." This statement undoubtedly referred to the islands of the Grand Manan Archipelagoin the Bay of Fundy and not to islandsalong the coastof Maine. A. E. Verrill, who edited and arrangedBoardman's list-of birds, quoted Boardman in his 'Catalogue of the Birds found at Norway, Oxford County, Maine" that: "A few appear to breed on islandsin the Bay of Fundy." It is apparent that the statement of x I wish to thank the officialsof the U.S. Fish and Wildlife Service for the facilities and opportunities they have so freely given for this work. Vol.194562] J GROSS,Status of Great Black-backed Gull 243 their breedingon the coast of Maine by W. A. Stearnsand E. Coues (1883) was basedon Boardman'spaper and not on new and original observations. This suppositionis borne out by reports of contem- porary authors. Everett Smith (1883), who wasstationed at Mathias in the service of the U.S. Coast Survey and who had corresponded and traveled extensively along the coast in gathering material for his 'Birds of Maine,' stated positively that no Black-backed Gulls bred on the coast of Maine. This statement was substantiatedby S. F. Baird who was well acquainted with the coast as superintendent of the U.S. Fish CommissionSurveys. Baird, Brewer and Ridgway (1884), in discussingthe nesting distribution of this gull, mention its presenceon islandsin the Bay of Fundy but did not includethe coast of Maine. The foregoingstatements make it clear that the Great Black-backedGulls were not breedingon islandsof Maine during the latter part of the nineteenth century. [See also Norton and Allen (1931).] At the beginning of the present century the National Audubon Society took an active interest in protecting the sea birds of this region. From that time on, numerousobservers, including William Dutcher, Arthur H. Norton, Ora Knight and others, made frequent and thoroughinspections of all of the important colonies. During this period the Black-backed Gull was common as a winter resident and a few stragglersremained during the summer, but not a singlepair was found breeding until the year 1928 when Jacksonand Allen (1932) found three pairs nestingon Duck Island of the Isles of Shoals. [See also L. O. Shelley (1934).] In 1931, Arthur H. Norton and Robert P. Allen (1931) made a thorough inspectionof the Maine sea-bird coloniesfrom June 23 to July 14 for the National Audubon Society. In an unpublished manuscriptthey reported finding the Black-backedGull breedingon ten islands concerningwhich they made the following comments: "Double-shot Island, several nesting; Little Duck Island, two pairs with young; The Brothers,at least two pairs breeding;Cone Island, severalnesting; Green Island off of Swan's Island, one pair nesting; Hardhead Island, one pair nesting [See also Berolzheimer(1932)]; Spoon Ledge, two nests found; Egg Rock in West PenobscotBay, several nesting; Yellow Ridge, one pair seen,one young ready to and Northern White Island, one pair of adults and one young seen." It is possiblethat Black-backedGulls were breedingon some of the above islands a year or two prior to 1931 but were not observedand reported. It is of interest to note that in the same year Richard Eaton (1931) discoveredthese birds to be nestingon North Gooseberry 244 GROSS,Status ofGreat Black-backed Gull [April[Auk: Island, near Salem,Massachusetts, on July 7, 1931. On July 2, 1944, F. Burnett (1944) found more than 30 young Black-backed Gulls on this island. From this small beginning,made lessthan 15 years ago, the Black- backed Gull has firmly establisheditself as a breedingbird along the northern New England coast and has extendedits range as far south and west as Cartwright Island off Long Island, New York [Arbib and Eynon (1940), Nichols (1942) and Wilcox (1944)]. It has recently been found nesting on rocks off Sakonnet Point, Rhode Island (Clementand Emerson,1944). Today, a conservativeestimate places the Great Black-backedGull nestingpopulation on this coast at no less than 3,500 individuals. With only five exceptions,islands on which the Black-backed Gulls werefound nestingwere alsoinhabited by Herring Gulls. The Black-backs, on the average, start nesting about ten days or two weeksbefore the Herring Gulls. They thus acquirethe choicenesting sites on the higher elevationsand roundedknolls. The nestsof the Black-backed Gulls, in addition to generally occupyingthe higher places,are larger, with nestingmaterials more widely spread, and are lessdeeply cupped than thoseof the Herring Gull. The materialsare usually of grass and small weed stalks and seldom are mixed with massesof turf, soil and large sticks which so frequently are a part of the structureof the Herring GUlFsnest. The eggsof the two species are similar in their color and markings but those of the Black-backed Gull average larger in size. Accordingto A. C. Bent (1921) the averageof a seriesof 59 Black-backedGull eggsis 77.9 x 54.2 mm. and the averageof 45 Herring Gull eggsis 72.3 x 50.5 mm. Although the nestsand eggsof each specieshave certain distinctive characteristics, there are instances,especially where the nests of both are closely intermingled in a crowded colony, where I have been unable to de- termine the identity of the nest without seeingthe incubating adult. During the last week of May we found that many of the eggsof the Black-backed Gulls had hatched whereas those of the Herring Gull were intact, with incubation of thosein the most advancedstages not exceedingtwo weeks.