22 ST•O•, Habits of the Herring Gull. [Jan
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22 ST•o•, Habitsof theHerring Gull. [Jan.Auk ON THE HABITS AND BEHAVIOR OF THE HERRING GULL, LARUS ARGENTATUS PONT. BY R. M. STRONG. Plates III-X. I. Introduction. VII. Reactions to stimuli. II. Methods. 1. Auditory. III. Social or community 2. Visual. relationships. 3. Chemical. IV. Feeding habits. 4. Other reactions. V. Breeding habits. VIII. Special activities. 1. Mating. 1. Flight. 2. Nest construction. 2. Bathing and drink- 3. Brooding. ing. 4. Care of offspring. 3. Perching. 5. General behavior IX. Comparison of diurnal of juvenals. and nocturnal activi- 6. Development of ties. bird after hatch- X. Variability and Modi- ing and life cycle. fiability in behavior. VI. Voice. XI. Migration. 1. Introductory. XII. Summary. 2. The "alarm cry". 3. The "challenge". 4. Other cries. I. INTRODUCTION. It is the purposeof this paperto describethe resultsof work whichwas begun with the ideaof studyingbird habitsintensively. I learnedthrough Mr. Henry L. Ward, curatorof the Milwaukee Public Museum, that coloniesof Herring Gulls were to be found breedingon islandsoff both coastsof the peninsulawhich forms Door County,Wisconsin, i.e. in GreenBay and in Lake Michigan (SeeFig. 1.) Thesebirds seemedto be especiallyfavorable for my purpose because:(1) they nestin rathercompact colonies on the ground and in moreor lessopen places so that many individualscan be seenand studiedto advantage,and (2) their considerablesize and largelywhite plumage make them among the bestbird subjectsfor the indispensablephotographic records. Furthermore, I had alreadyhad someexperience with thesebirds, especially during THE AUK, VOL. XXXI. PLATE III. THE •TRAWBERRY ISLANOS FROM THE EAST. ISLAND ON LEFT OCCUPIED BY GREAT BLUE HERONS. OTHER TWO ISLANDS BY HERRING GULI•S. 2. GR^VEL ISLAND. Vol.1914 XXXI] J STRONG,Habits of •heHerring Gull. 23 July, 1907,when I visiteda breedingcolony at Gull Island in Lake Superior,near Marquette, Michigan. On June 20, 1911, I madea preliminaryexploring trip in Green Bay startingfrom my headquartersat Ephraim, Wisconsin. With the aid of a motorboat, the StrawberryIslands, the SisterIslands, Fig. 1. •Vl•p showing loc•tions of Gull colordes in region of GreenB•y, Wisconsin. and Hat Islandwere all visitedduring the day, and coloniesof HerringGulls were found breeding on all of theseislands except at the largestof the StrawberryIslands (See Plate III, Fig. 1) which supporteda colonyof Great Blue Herons. As it did not seempracticable to attempt to live on any of the 24 STroNg,Habits of theHerring Gull. [Jan.Auk islands,I thoughtit bestto stayat Ephraimand depend upon small boats for transportationwhenever a visit was made to the gull colonies. Unfortunately,boats were not alwaysavailable and the weatherwas not favorableon manydays. Work wascarried on at the Sister Islands on June 26, July 12, and July 15; at Middle StrawberryIsland on June 30 and July 29; and at Gravel Island July 18 and 19. Anotherperiod was spentat Middle Strawberry Island beginningat 7:20 r. M., July 7 and endingthe next day at 7:05 A.M. So much time was taken by preliminarystudies that my experimentalwork at the breedingplaces was barely begun when the season ended. Other experimentswere begun with some juvenal gulls which were taken from their nestingplaces to Ephraim and were kept in a pen (SeePlate IV, Fig. 2). Thesebirds were removedto Chicago in Augustwhere experiments with them are still in progress. Ref- erenceswill be made in this paper to observationsmade on these captivegulls. The workin Chicagohas been made possible through the kindnessof ProfessorsAngell and Carr of the Departmentof Psychology,in givingme outdoorcage accommodations. The only speciesof gull discussedin this paper exceptwhere otherwisestated, is the Herring Gull. II. METttoI)S. Like otherobservers, I founda tent or blind indispensablefor the study of the birds at their breedingplaces. On approaehlnga breedingcolony of gullsa wild panicbegins which doesnot ceaseso longas the intruderappears to be in the immediatevielnity. I had a tent made similar to that describedby Sawyer,• with somemodifications. It was about four feet high and six feet long at the bottom. The cover was made from dark greencambric lining cloth, costingseven cents a yard. The entire covercould be foldedinto a packagesmall enough to go into a coatpocket. After the first trip, extra openingswere made to facilitatetaking a Sawyer, E. J, A SpecialBird-Blind. Bird Lore, VoL XI, no. 2, March-April, 1909, pp. 71-73. O•xo page of $ex$ figures. THE AUK, VOL. XXXI. PLATE IV. 4 1. BLIND ERECTED ON MIDDLE •lqRAWBERR¾ 2. JUVENAL GULL SWALLOWINGFISH ABOUTTEN INCHES LONG. Vol.1914 XXXI] J STRONG,Habits of theHerring Gull. 25 photographsin variouspositions. Whennot in usethese apertures were closedby cloth doorswhich were provided with hooksand eyes such as are used by dressmakers,but of extra large size. An openingabout five inchessquare in the top servedquite suc- cessfullyfor ventilation. Such a tent can be set up on rocky placeswhere stakes cannot be used; and there are no guy linesto obstructthe camerafield. It is possibleto seemore or lessof what is goingon outsideof the tent throughthe cloth itself,although holes of smallsize give a clearer view. When dark clothing is worn, one'smovements inside are not noticed. The lower margin of eachside and end of the tent washeld down by a pole which ran througha hem in the cloth, and the endsof the poleswere anchored with weightswhen a wind wasblowing. Thus in Plate IV, Fig. 1, piecesof wood appearat the corners,for this purpose. A brisk breezewas blowingwhen the picture was taken as may be seenin the bellyingof the sideof the tent. This tent with considerableadditional anchorage in the form of rockswent throughan unusuallyviolent stormwithout injury or displacernent.Only a smallportion of the heavyfall of rain came through the cloth. It was found wise to carry permanenttent polescarefully fitted to the cornerblocks, in a bundleas a part of my outfit. Drift boardswere used as a floor. The chief objectionto this form of tent is that it is not high enoughto permit the observerto stand upright. During a long day, I couldnot avoid becomingmuch crampedeven when I tried shiftsfrom a sitting to a recliningposition and soon. I havesince useda tent of similar form but larger and over six feet tall. The polesare all of bambooand the cornerfittings are of brass. The numberof openingshas beenreduced but they have beenplaced in carefully selectedpositions. The sidesand ends are all sewed togetherexcept at onecorner where the entranceis placed. Tapes are provided for closingthe entrance. This tent is much neater and far morecomfortable, and it canbe setup with the adjustments of equipmentin lessthan fifteen minutes. I foundit necessary,as has been the experienceof others,to have a companionleave the tent after having beeninside with me. He would also leave the island with our boat, and he would not return 26 STRONg,Habits of theHerring Gull. [Jan.Auk until a time agreedupon for the trip home. During this periodI could not emergemyself without spoilingall chancesfor the day. After the departureof my companion,the apparentlynormal life of the colonywas largely resumed in a few minutes. This precau- tion was not observedat Gravel Island, and the gullsthere did not comevery near the tent during the severalhours my companion and I spentin the tent. Apprehensionwas shownin other ways, also. Ward's experienceat Gravel Island when he had no one to leave the tent was similar and his account I follows. "The next time that I visited the colony, three days later, I was alone. I beachedmy boat, set up my tent and entered. Six minuteslater the first of the youngreached the island,followed two minuteslater by the settlingof the first adults,some on the islandat its most distant point, but mostin the water. It was an hour and thirty- five minutesbefore any cameclose to the tent, and not until half past four the next morning,or thirteenhours after settingup my tent, did the first onealight on it. The gullson this occasionwere quite uneasyand werefrequently thrown into a panicby their own actions. The suddenalighting of a bird, or a fight betweentwo, wouldfrighten one, who, not waitingto seewhat was the trouble, wouldtake wing,followed by oneafter anotheras the panic-formed waveswept over the island,leaving it almostbare of gulls. Fortu- nately they quickly recoveredand returned, but their alertness and the frequent'wak..wak, wak, wak' of their note of suspicion showedthat somethingbothered them. Apparentlythe departure of two peopleand the boat the first visit had deceivedthem into thinking that all had left the island, while on the secondtrip, althoughI had disappeared,yet no onehad left the island,and for thirteen hoursthey rememberedthis and were suspicious.After the first gull lit on the tent they abandonedtheir suspicionsand were as familiar with it as on the previousday." A smallfolding camp chair was found a greatconvenience, but boxesare often availableon a beachand theseserve very well as a seat. qXwocameras were used, one a 5 X 7 Graphlcxwith a Tcssar • W•rd, }{. L. Notes of the Herring Gull •nd the Caspian Tcrr•. Bull. Wis- consin N•t. Hist. Soc., Vol. IV, No. 4, October, 1906, pp. 113-134, 2 plates. 'Vol.1914 XXXI] J STRONG,Habits of the Herring Gull. 27 lens,and the other a foldingtripod camera size 3{ X 4{ incheswith both a lensshutter and a focal-planeeurtaln shutter. The smaller camerawas moreoften used,and frequentlywith only one of the two eombinatlons of the convertible lens whleh it carried. I have founda convertiblelens exceedingly useful in bird photographyas a long-focuslens is frequentlyneeded. It has been my experience that it is not praetleableto use large diaphragmopenings in bird photographybecause of the flatnessof the field whichthey involve when the camerais as near as is necessaryfor photographing birds. I rarely usean openinglarger than U.S. 8 or F. 11. III. SOCIAL OR COMMUNITY RELATIONSHIPS. An interestinganalysis of a Herring Gull communityhas been made by Herrick.• He speaksof "family-units" and "family domains"which he saysare guarded"wlth relentlessvigilance." These preelnetsmay be small and closetogether in a crowded breedingplace.