THE AUK A QUARTERLY JOURNAL OF ORNITHOLOGY VOL. 61 OCTOSER,1944 NO. 4 THE PRESENT STATUS OF THE DOUBLE-CRESTED CORMORANT ON THE COAST OF MAINE• BY ALFRED O. GROSS Plates 19-œœ GREATchangcs in thc distribution and abundanccof ccrtain sca birdsof thc islandson the coastof Mainc havetakcn place in rcccnt ycars. For cxamplc, thc first rccordsof thc ncstingof thc Grcat Black-backed Gull, œarus marinus, were made on some of the more castcrnislands as rcccnfiyas 1951. Today this gull is abundantand ncstson many islandsalong thc enfirc coastlinc from the Bay of Fundy to the Islesof Shoalsand beyond. The Herring Gull, œarus argentatussmithsonianus, likcwisc has so grcafiy incrcascdin num- bers that the U.S. Fish and Wildlife Service has bccn forced to take dcfinitc stcpsin controllingthis bird which at thc turn of the cen- tury was thrcatcncdwith cxtcrmination. Othcr spccicshavc cxpcri- cnccdsimilar changcsbut none have bccn more spcctacularthan the extraordinarycorecback of thc Doublc-crcstcdCormorant, Phalacro- corax auritus auritus, commonlyknown on our coastas the "Shag." Thc first accountsof thc cormorantson thc Ncw England coastare to bc found in the writings of Captain John Smith (1616) who visited this regionin 1614. Later, others,including William Wood (1654), ThomasMorton (1657),and JohnJossclyn (1674), indicated that the cormorantswcrc breedinghere in large numbers$00 yearsago. For reasonsthat arc not dear, the cormorantwas completely exterminated as a brccdingbird on thc Maine coastby thc ninctccnthccntury. EvcrettSmith (1885)wrotc of the Doublc-crcstcdCormorant as fol- lows: "Nonc brccd on thc coastof Mainc, although somcarc hcrc all summer. Thcsc arc chicfly immaturcbirds which kccp togcthcrin flocksand habitually rcsort to the samelcdgcs each night to roost." x Contribution Number •e, Bowdoin-Kent Island Scientific Station, Kent Island, Bay of Fundy, New Brunswick, Canada. 513 THE Aux{, VOL. 61 PLATE 19 DOUBLE-C,RE•TED CORMORANT.--THE MARBLEHEAD COLONY ON JULY 5, 1944. THERE WERE AN ESTIMATED 2000 YOUNG IN THE ENTIRE COLONY, MOST OF WHICH WERE IN NEARLyCOMPLETED JUVENAL PLUMAGE. A FEW WEREABLE TO FLY. [Auk GRoss,Double-crested Cormorant in Maine Recordsof an attempt of thisbird to reftstablish itself as a nesting bird on the Maine coastare containedin an article written by Ora W. Knight(1896). On July2, 1895,he visitedBlack Horse Ledge, off Isle Au Haut, where he found two nestswith three eggs,one nest with a singleegg, and other nestsin processof construction.He writes further: "Mr. Charles K. Reed informs me that i•a June 1892 and 1895 he took setsof the Double-crestedCormorant eggsnear Isle Au Haut, andbeyond doubt he visitedthe samecolony of birds." In anotherpaper, Knight (1900)mentions visiting Black Horse Ledge on June23, 1896,as follows: "We found a numberof Shagson the ledge,but onlytwo nests were to be found. Oneof thesewas incom- pleteand the othershowed the imprintof threeeggs, and as we afterwardslearned that other collectorshad been there, the eggsun- doubtedlytaken by them.... Owingto the attentionsof collectors it is somewhatdoubtful if this speciescontinues to breedmany more yearsalong the Mainecoast, as the only breeding colony I haveany knowledgeof is on the pointof extermination."That thisattempt of the cormorantswas quickly extinguished is borne out by visitsof othernaturalists to theledge in subsequentyears. Black Horse Ledge waseven deserted as a roostingplace of the cormorantsbefore 1907. Mr. A. H. Norton made annual visitsall along the coastduring the yearsfrom 1902to 1923and, although many cormorants were foundroosting on variousledges and islands, not onewas found to be nesting.About 1925 the Cormorantsstarted nesting again and in a surprisinglyshort time firmly established themselves asbreeding birdson the coast. In 1931,Mr. A. H. Norton and Robert P. Allen (1931)found the following breeding colonies: Old Man Island, 1,000 adults;Pulpit Rock, 100 adults; Spoon Ledge, 40 adults; Marblehead Rock, 600 adults;and Old Hump Ledge,8 adults. In 1935,Howard L. Mendallpublished his comprehensive paper on the Homelife and EconomicStatus of the Double-crestedCormorant. In thisreport he includesthe colonies listed by Nortonand Allen and statesthat in 1935the Marbleheadcolony had increasedto 700 birdsand the Old Hump Ledge colony to 400birds. He alsoreported 78 nestingbirds on CrescentLedge in 1934,but thiscolony was abandoned in 19•õ. Duringthe past three years it hasbeen my good fortune to serve as a Collaboratorwith the U.S. Fish and Wildlife Servicein con- nectionwith the HerringGull ControlProject. I wishto expressmy gratitudetoMr. S. B. Locke, Regional Director, who made it possible forme to have this exceptionally fineopportunity tostudy the sea-bird vo•.6•] cross,Z)o,•bZe-c,'ested Co,',•o,'a,,t •,, Mai,,e 515 1944 .• coloniesof the entire Maine coastand to recordthe changesthat are takingplace. This paperis concernedprimarily with an accountof the recentincrease and presentstatus of the Double-crestedCormorant but other specieswill be consideredin subsequentreports. In 1955, there were but six known Cormorantcolonies and only oneof these,Old Hump Ledgein MuscongusBay, was west of Penob- scot Bay. In 1945, we found prosperouscolonies along the entire coastfrom Old Man Island,our mosteastern sea bird colony,near Grand Manan Channel, New Brunswick, Canada, to Duck Island, Islesof Shoalsjust insidethe New HampshireState boundary off Portsmouth. The chiefobjective of the U.S. Fish and Wildlife tripswas to visit gull-inhabitedislands; the cormorantcolonies were incidental-hence someof the latter probably were missed,but even so, 97 colonies werevisited which containeda total of 9,118nests representing that many pairsof birds. Furthermore,since each year the time of visit- ing the islandson which the cormorantswere nestingwas compara- tively early in the season,the last ten daysof May and the first three weeksof June, the numbersof nestswere probably smaller than theywould be at the height of the nestingseason. A very conservative estimateof the number of adult Double-crestedCormorants nesting along the Maine coastin 1945 is 10,000pairs or 90,000individuals. There are at least 5,000 non-breedingbirds which roosted on the numerousledges and islandsall alongthe coast,making a total popu- lation of 95,000 cormorants. The numbers have now increased to the point where many complaintsare being made againstthis bird by the fishingindustry for its allegeddepredations on fish. A move- ment is on foot in this stateto passlegislation taking the cormorant off the protectedlist. If an unbiasedinvestigation does prove the birds are doing a real damage,it would seemadvisable to have the matterof controlplaced under the directsupervision of the stateor federaldepartments rather than to allow the indiscriminateshooting of the birdsby irresponsiblepersons. The latter coursewould tend to undo much of our work of conservationand it would prove to be disastrous to other sea birds such as the Eider Duck which nests on manyof the sameislands inhabited by the cormorants. The fishermenprobably have sound grounds for their complaints althoughtheir statementsare sometimesexaggerated. There seems to be somequestion as to the reporteddamage by the cormorant. H. L. Mendall (1955),who conducted studies on the economicstatus of the cormorantin Maine, states:"The chargethat the Cormorants 516 GRoss,Double-crested Cormorant in Maine LF AukOct. are detrimental to the fishingindustry are shown to be largely un- founded,the greaterpart of the bird's [ood being made up of [orms which are of little or no use to the fishing industry. In somecases, the birds are a benefit through their fondnessfor undesirablefish." The cormorant, unfortunately, was not included in the list ot' migratory non-gamebirds protectedby the Migratory-birdTreaty Act and Regulationsratified in 1916. The protectionof this bird in Maine comesunder the jurisdictionof the StateDepartment of Inland Fisheries and Game. To presentthe statusof the Double-crestedCormorant on the Maine coast,all o[ the presentexisting colonies known to me are listedin order beginning with the most easternone situated on Old Man Island and proceeding[rom east to west and south to the Maine- New Hampshirestate boundary line. To assistthe readerin find- ing the islandson maps, the approximatelatitude and longitude are given. A brie[ descriptiono[ the islandsand a historicalaccount of the cormorants,especially during the past three years,are also included. It will be seenthat not only havethe numberof coloniesincreased, but the populationsin 1943were oftendoubled or tripled and in a few caseswere more than four times the numberspresent in 1941. This increase in the numbers of cormorants and the extension of their breedingrange are not peculiarto the coastof Maine. Dr. Harrison Lewis (1942)reports that the Double-crestedCormorants are on the increasealong the north shoreof the Gulf of St. Lawrence. On June 11, 1942,Harold S. Peters (1942)found a colonyof 100 nestsat CapeTryon, PrinceEdward Island, Canada, which constitutes the first recordof thesebirds nestingon that island. In Massachusetts,Baird, Brewer and Ridgway (1884) stated: "It is believed once to have been resident on the northern shores of Massa- chusetts,but long sinceto havebeen driven away." Today this bird has again establisheditself as a nestingspecies on that part of the New England coast. JosephA. Hagar (1941) discovereda colony of 53 pairs of Double-crestedCormorants breeding at Shag Rocks near BostonLight at the entranceof BostonHarbor,