nicol - homing ability of carrier pigeon

8/13/2019 Nicol - Homing Ability of Carrier Pigeon

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9,86 NxcoL,omingbility fCarrierigeon rAukAprilLas Vigas, 7,900 t., July 30-31, 1942; 2 c, 1 9, Cofre de Perore, 10,500 t., July 30-August 4, 1942 [malesaveraged46.3 grams (40.0 to 53.7); two adult females,38.3and 39.8 grams]. This sparrow is characteristic of the coniferousbelt of centralMxico. It oeeurred on all the high mountains visited by us (Cofre de Perore,Orizaba, Popoeatepetl, Iztaeeihuatl, Tres Cumbres, etc.) at elevations ranging from7,900 feet at Las Vigas to nearly 14,000 feet on Mount Popoeatapetl. It preferredopen meadowsand was one of the common timberline sparrows. One of the femalesfrom Las Vigas s a nearly full-grownyotmgof the .year. The adult femalehad awell-developed brood patch and the testes of the two males were considerablyen-larged.*Jimophila rufescensrufescens (Swaiuson), Rvs S'.iRROW.--I 9, Jalapa,4,500 ft., July 2, 1941. Widely distributed in central Veracruz, preferring thickets iuthe vicinity of water.Juncophaeonotus haeonotusWagler, MxmN JvNco.--1 c, I_asVigas, 8,000 ft.,August 4, 1942; 1 c, Cofre de Perote, 10,500 ft., August 4, 1942 (testes small;weights 21.5 and 22.5 grams). 3. common breeding bird in the conifer-dad areas ofthe Mexican plateau, occupying an altitudinal range from near 7,000 feet to timber-line (specimenswere taken on Mr. Popoeatepetlat 13,500 feet).

Departmentof Fish and GameCollegeStation, Texas

THE HOMING ABILITY OF THE CARRIER PIGEONITS VALUE IN WARFARE s

BY LIEUT. J. A. C. NICOL ROYAL CANADIAN CORPS SIGNALSTHE homing ability of the carrier or homing pigeon is, in a generalway, well known--so much so that this, their chief characteristic, isfrequently employed n metaphor and simile as an expression f pre-cision and accuracy which would rebound much to the discomfitureof the writer were all in full possession f the relevant facts. In thelight of recent occurrences,he subject s not without topical interest

and the biologist, on examining the data and experiments describedbelow, may be able to fill in someof the gaps which puzzle the pigeonenthusiast. For the latter invariably knows his birds well, developshis own method of selecting he wheat from the chaff, from personalexperienceconstructshis own theories, but all too often fails to viewhis subject objectively and shroudshis conclusions ith an anthropo-morphic and teleologicalaurora that defiesclear vision.It is the intention of the writer to review in this paper the knownachievementsof the homing pigeon; the uses o which they have been1 Submitted for publication in accordancewith the Provisionsof Canadian Army Orders and withthe approval of Canadian Military Headquarters. Passed by Military Advisers to the Press Censor-ship, War Office September 22, 1944. Cecil M. Wills, Major G. S.2 The terms carrier and homing pigeon are used nterchangeably in this paper,


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VoL 62]1945 NICOL,omingbilityfCarrierigeon 287put in peace and war (described or the benefit of interestedreaderswho may not have had access to the scattered literature on thissubject); and to discuss he ways in which they have been used n thepresent war in so far as it may be told. Finally, an attempt will bemade to correlate the problem of the homing ability of this domesti-cated specieswith the homing abilities of migratory birds in generalin order to discoverwhat light the former will shedon the subjectas awhole.

Darwin (1) has shown that the homing pigeon has been evolvedfrom the wild rock-dove which still breeds n western England andwhich, by continued artificial selection, has been developed nto thebird employed today. Moreover, the modern homer is the result ofthe cross-breeding f several distinct varieties of domesticpigeon and,as such,originated n the nineteenthcentury although only within thepast hundred years have its homing abilities been widely used. Pigeonracing in the past has been a very popular sport in western Europeand even more so in Great Britain. To a smaller extent pigeonraceshave been held in North America where some of the events have beencharacterized by abnormally long distances. Annually, the youngand the old bird races have attracted many participants and as theresult of the selectionwhich these raceshave exercised,a bird strongin physique,which can be relied upon to return to a known oft afterproper training, has been obtained. Certainly the homer s larger thanits wild progenitor. Little is known of the homing ability of the rock-dove whose major flights seem to be from feeding grounds o socialnesting sites. Consequently, the following is the maximum whichcan be predicated :--

1. Selection has favored homers with best physique and homingability. It is impossible o distinguish the relative importanceof these two factors in the case of any winning bird.2. The modernhomer possessesoming ability at least as nice asthat of the natural species.

Details of training programsusedby pigeon acersare as varied asthe number of participants and every gradation can be found from thecaseof the man who swearsby the effectsof night water or chimneysweepings o the person who calculateshis procedure with graphicaccuracy. The following, however, is a general and representativepicture. Young birds are purchased or hatched in a loft and aresettled in that site as the.t permanent home. They are weaned andgradually learn to fly short distances. By judicious attention andhandling, the fancier accustomshe bird to his presence. They are


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9.88 Nmos.,omingbility fCarrierigeon rAukAprilreleaseddaily for exerciseand they fly about the immediate loft area,gradually becoming stronger on the wing and learning to maintaindose flock formation ( kitting ). They are fed only on return to theloft and birds which fail to enter the trap readily may be penalizeduntil their performance mproves. Some particular call is utilized tocall the birds .back to the loft, usually the sound of dry corn rattlingin the feed tin. After this preliminary training, birds are selected orthe different events and are sent away varying distanceson the flightroute whichwill be followedduring the actual race. They are releasedat thesepoints and fly home. A program of tossesor a long-distancerace might be somewhatas follows: / mile; /; 1; 1; 2; 3; 5; 10;16; 25; 40; 60; 90; 130; 175; and 250 miles. And inthefinaltoss,at the time of the actual race, the bird may be jumped to 500 miles.Breeding s utilized as a stimulus to return by certain fanciers who tryto arrange that the racing birds will have eggsor young at somepartic-ular stage of development at the time of the race, and breedingmaybe employed also to alter the time of the molt so that the bird willhave the maximum number of pinions on race-day.This homing ability of the pigeon, n commonwith the migratoryhabits of other species,early attracted notice. Most of the classicalreferences o message arrying by pigeonscan be discounteddue totechnical inaccuracies,and it is not until the nineteenth century thatwe find authentic instances. During the siege of Paris, homers werecarried out of the city by balloon and were used to carry correspond-ence nscribedon collodion ilm into the beleaguered ity. The propor-tion of returns was about 17 per cent. Despatcheswere alsocarried bypigeon during the siege of Ladysmith and to isolated garrisons nNigeria shortly after the Boer War. These birds have also beenemployed by various prominent newspaper companies to obtaindetailed news of sporting events in time for their several editions.But it was in the war of 1914 to 1918 that the homing pigeonwas firstextensively used as a means of communication. Here it played aremarkable r61e n many fields. Birds were sent out with trawlers andmine-sweeperswhich at first lacked wirelessas a means of communica-tion. They were dropped by plane over enemy-occupiederritory tobe usedby agentsand sympathizers. And, finally, thousandsof birdswere used by the services on the western front as an aid to com-munication.

The method employedby the army was briefly as follows. Loftsweresettledsomewhere ehind he lines, re.quently t divisionalhead-quarters and preferably dose to a signal office or messagecentre.Young birds werefavored and thoroughlyaccustomedo their location


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Vol. 62'[1945 Nmos, omingbilityfCarrierigeon 9.89by long residenceand exercise lights. They were then carried awayincreasing distances from the loft along the route which would befollowed during actual operations and released o fly home. Finally,when trained, they were carried up to battalion and company head-quarters n suitable panniersby despatch iders and orderliesbefore anattack and were releasedby commanderso send eports and requestsfor support o headquarters n rear. Osman (2) states hat suchbirdshorned aithfully in 99 per cent of the cases.The advantagesof using pigeons n this type of warfare werenumerous. It was very economicalof human lives since many runnerswould otherwise have been killed in crossingshell-torn country withmessages,whereas the birds were hard to shoot on the wing and couldpassover shelledareaswith relative impunity, and even when woundedwould presson as long as they couldfly. They were not disturbedbyshell fire as long as the loft itself was not hit nor badly shaken. Theywere much less susceptible o certain types of poison gas than men.Skilled operatorswere not required to release hem in forward andexposed areas. Against this must be set the fact that they wereunreliable in fog, smoke or darkness; that they would only carrymessagesn one direction, and that they lacked mobility in the sensethat long residencewas requiredbefore he bird couldbe relied upon asa messenger n any locality.On the outbreak of hostilities n 1939, the use of pigeons n warfarerequired re-examination since t was soon apparent that many of thesignalsproblemsof the War of 1914 to 1918 were not applicable o thisnew warfare with its terrible alterations n tempo and method. Pigeonsare again being carried by naval vesselsand also by planes of the airforces. The latter have evolvedspecial echniquesor their releasefrom aircraft but, interesting as suchdetails are, they lie outside thescopeof the presentpaper. Among the ground forces,with the adventof more mobile warfare in 1940, when rigid lines became replaced bydefended ocalitiesand maneuveragain becamepossible, he possibilityof using pigeons as a means of communication became questionable.They are obviouslyof greatestvalue to forward elementswhosemeansof communication are slight. In such areas, telephone lines at firstare flimsy and exposed o frequent interruption, and wireless s ofshort range and often hamperedby atmospherics t night. The useof visual signalling and messengerss subject to interruption andexpensive n personnel. Caeterisparibus, pigeon service could parallelor supplantsuchmeas of communicationnd, in the caseof isolatedparties cut off from the rest of the force, the birds could be droppedby parachute. Much work and ingenuity have been expendedon this


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[Auk290 Nmox,,omingbilityfCarrierigeonsubject by pigeon fanciers in the armed forces and their results arediscussed below.

We may considerthe several problems which have been met asfollows:

1. Training pigeons or maximal mobility.2. Training birds to fly at night.3. Training birds for two-way communications.Problem 1.--Training birds or maximal mobility.

Details of such raining no doubt vary among he armiesof differentnations, but the following will serve as a representative example.Small lofts are used, either light enough o be manhandledor mountedon trailers. Young birds are chosen,usually about five weeksold, andare settled in these ofts. The initial part of their training consists fmakingthe birdsstrongon the wing, kitting (i.e. flock formation)and teaching the birds to trap readily. Fundamentally the lastmentioned is basedon a simple conditionedreflex established hroughcalling the birds into the loft by rattling feed in a can or blowing awhistle. Then, as soon as the birds pass through the trap, they aregiven their allowanceof corn. Thus the birds come to associatecertain soundsand the act of trapping with food. Immediate andautomatic trapping s obviouslyof great mportancewhen the recoveryand delivery of a messagen the shortestpossible ime are set at apremium. At this stage the lofts are moved short distancesdaily inorder hat the birdswill not becomerrevocablyaccustomedo any onespot. When strong on the wing they are packed in panniers andcarried away short distances or release. Following this preliminarytraining, lofts are moved greater distances, up to 20 miles or moreevery three to seven days, and at each location the birds are giventosses in a direction set as the axis of advance. A limit of these tossesis tentatively placed at 50 miles. In caseswhere time of return isvery long or somebirdsare lost altogether,earlier stages n the trainingmust be retracedand repeated. Finally, the birdsare releasedn pairsat suitable intervals so that they cannot kit together and messagecarriers are affixed to their legsso that they can becomeaccustomed owearing them.The objects sought in such a training program are patent. Owingto the facility with which a bird localizes tself to any one place, thelofts are moved frequently to prevent the crystallization of such afixation of association. There is no good reason or assuming hat, asa result of such training, the bird's basic tendency to become abso-lutely attached o a givenspot s weakened incea kit of suchmobile-


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Vol. 62]1945I NzcoxHomingbilityfCarrierigeon 291trained birds, when established n any particular location for severalweeksor months, are just as difficult to settle in a new locality as birdswhich have never been moved any time from a fixed loft. What itdoes accomplish s to prevent the development of a closeassociationof loft with a particular. ocality. During the first day, preferably inlate afternoon or evening, the birds are released or exercise. Theyfly about the loft area for ten or fifteen minutes and are then called infor food. On subsequentdays they are given tossesat selectedandincreasingdistances, .g., 1, 2, 5, 10, 15, 25 and 45 miles, espectively.These stages are always on some predetermined axis of advance.Tosses re given only in clear weatherand during daylight. Visualtraining is obviously the only factor considered. In the initial flightthe bird sees he topographyof its immediate surroundings nd estab-lishesan associationof home and food with thosedetails of objectsandspatial relationship which differentiate one spot from another. Onsubsequent osses t gradually learns the surface eatures of the groundit will traverse, with each step in its training based on that whichpreceded it, and the greater the number of such flights, the fasterdoes t home. Thus far the tale is simple,but it is necessaryo analyzeall those cases in which the bird fails to return or in which the time ofreturn is abnormally long.The first instance s that which is known among anciersas a fly-away. They say the birds are flighty and, castinga measuredglanceat the sky, note that the air is misty. Whatever terminology isemployed, t remains a fact that birds, on occasion,when first releasedin a new locality, will fly about the loft for a short time and thengradually veer off and fail to return even though the loft is in full view,the birds are hungry, and the loftsman to whosevoice they are accus-tomed is calling them incessantly and rattling the feed can. Subse-quently the birds may be found at the previous location of the loft,quietly feedingon the ground at the exact spot where the loft had beenplaced. They may visit severalsuchold loft sites n turn and, if theloft has been moved many miles from the last position and the birdsare in completely new country which they have never traversed before,they may disappear into the blue.' The factors operating here arecomplexbut, in so far as they may be analyzed,the followingseems obe the explanation. The loft representso the bird food,water, a placeto bathe, salt and grit of which it is inordinately fond, a place to roost(and each bird in the loft choosests own particular perch) and finallyprotection. The potency of this last factor is seen n the-reluctancewith which the birds will enter the loft after it has been invaded bysomepredator, suchas a cat or stoat. But the sight of the loft itself


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9.99. NxcoL,omingbility fCarrierigeon [AukAprilis not enough for the bird which, as the result of all its training, isaccustomed o direct itself to the locality of the loft by the aid ofcertain visual landmarks and, when in the immediate vicinity of theloft, to its exact location by the peculiar topographical elationshipofthat spot to its surroundings. Therefore, no matter how strongly theconditioned eflex that signifies ood may be established n its neuralsystem, it may obey impulses correlating flight to visually knownlocalitieswith food and fly off to somepreviouslysignificant ocality.The bird has seen ittle or nothing of its new location, only part of thepanorama s true the loft--and that is situated n false surroundings.To overcome his difficulty the following procedurehas usually beenfound successful. The birds are kept enclosed or some time at thenew location before they are releasedand they are permitted to viewtheir surroundings ither by turning the loft about regularly or by theuse of an aviary; they are given a few grains of corn before release ocorrelate eedingwith their new surroundings; nd they are releasedlate in the day when fading light discouragesxtensive light, since hepigeon s essentiallya diurnal bird.Falling within a similar category are those eases n which the birdis required to fly over old flight routes. Although the bird may havebeen thoroughly trained over part of the new route and may havesuccessfully ornedon frequent occasionso its loft, yet, when tossedover areas which it has traversed on earlier occasions when its loft wasdifferently situated than at present, it may descendand fail to return.Here again, latent memory predominates, einforced by the presenta-tion of visually known landmarks and divorced from the pull whichwould be exerted by the features of its true loft site, and the birdobeys he more immediate call. Figure 1 representsone of the severalsuch eases which have come within the writer's ken. Movements oflofts are depicted numerically in the order in which they occurred;position 6 was reached approximately six weeks after position 1 wasoccupied. Tossesare shown by the length and direction of arrows.These were, in general,north until position6 was reached. Here itbecamenecessary o train birds south of the station to fly over route q.Tossese, and ' were successful ut only 40 per cent of the birdsreturned from toss and only two birds out of 30 from tossq,althoughthe loft had been in position for three weeks before the last two tosseswere essayed. Consequently, south of position 6 the result was afailure. It is apparent from this example that the use of pigeons n awithdrawal where they may be required to fly over old and disusedflight routesmay present nsurmountableobstacles.Of the additional factors, with the exception of natural and artificial


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Vol, 62]1945 1NTICOL,omingbility fCarrierigeon 298

Legend:-->Drecti0n(DistanceToss

Txr-om 1.--Training of birds over disusedlight routes.death-dealing agencies,which may hamper or prevent the bird'sreturn, one other will be described which falls within the writer'sexperience namely, character of the terrain. Civilian fliers areagreed that pigeonsare reluctant to cross arge bodies of water andhilly country and, in the latter ease, end rather to follow valleys andgaps n the hills. Therefore,when training birds to fly over roughterrain, the practicehas been o tossbirds at consecutive ointswhichlink up a ght route following valleys and gaps and which outflankhilly obstacles. Figure 2 givesan exampleof difficulties ncounteredin such training and a solution hat was found. Contoursabove 400feet are shownat 50-foot vertical intervals. L represents he positionof the loft; pointsA, B, C, D, E and 17, n that order, are points atwhich the birds were tossed. One hundred per cent return of birdstossed n good time was experienced rom points A to D. Birds werevery slow in returning and 10 to 15 per cent losseswere encounteredwhen they were releasedat points E and 17. For the last two pointssuccessive ossesat Dz, Ez, 17,G and H were substituted. In theseeases he birds horned n good time and losseswere negligible,one totwo per cent. All experiencen training the carrier pigeonemphasizesthe important part which vision plays in its homing ability. In


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294 co, ttomingbility fCarrierigeon Aukpril

TXT-VmURE.--Training f birds n hillycountry.the mmediatease nderiscussion,rregularerrainelimitedhevision of the bird. Tossesat t3 and F were relatively unsuccessful,and this may be ascribed o the hills and dills which lay across hebirds' path. Yet on subsequent osses,when points were followedalong ow ground inking water courses etweenhills and opencountry,much greater success as attained. The bird is balked by steepriseswhere surface features present sharp transitions and its flight conse-quently tends to becomecanalized along routes where the panoramadisplays inconsequentialalteration.Problem2.--Training birds to fly at night.Since he homingpigeon s essentially diurnal bird it is very difficultto train as a night flier. Much evidence rom competitive acesshowsthat in long flights the pigeon will alight at dusk and continue itsflight at dawn the next day. Such birds in cross-channelaces haveremained overnight on ships at sea; and times of return substantiatethis hypothesis. However, certain British fanciers have recordedsuccessn training their birds to fly in twilight in caseswhere theirlofts were situatedat distances reater than average rom the pointof release,and the time of flight might be expected o exceed he hoursof daylight. Priestley (3) records hat in the war of 1914 to 1918 suc-cessfulexperimentswere carried out in the British Army on nightflying. The birds were given tossesat increasinglygreater distances


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VoL 62]1945 NICOL,iontingbilityfCarrierigeon 295from the loft and the trap was illuminated with a lamp of low candle-power shielded from a'6rial observation. Similar work has been donein the presentwar. The loft is static; that is to say difficultiesare sogreat in this form of training that it is not possible o move the birdsat frequent ntervals. The birds are given tossesrom twilight on intodark at distanceswhich increaseup to a maximum of 20 miles. Thebirds take longer to return than by day. Of the several methods oftraining the following seem to have attained equal success:

1. Birds are kept by day in a darkened loft which is illuminatedwithin after dark.2. The loft is not darkenedduring the day nor illuminatedat night

and the birds are releasedduring daylight for normal exerciseflights.3. The rapof h oft s lluminatedith weakight r he oof rsidecoveredwith a white marker. The writer's experiences thatbirds will trap more readily when the trap is illuminated at night.Problem&--Training pigeonsor two-wayservice.

Normally the pigeon will fly only over one direction of its route andmust be carried to the point of release. Its homingpropensitydependson the attraction of the loft and all that this structure represents.Within this loadstone the following factors may be differentiated:breeding, ood, salt, grit, shelter, oosting,protection. The process ftraining pigeonsto perform a two-way service consistsof dividingthese factors between two points. Breeding can be discountedsinceit is discouragedn army lofts. The birds are settled in a static loft,placed in baskets, carried away a short distance to a point withinsight of the loft and fed in the basket. They are then released o flyhome. This process s repeated and the birds learn to correlate theposition of the basket with food. Gradually the basket is removedfartheraway until the desired eliverypoint s reached. At eachstage the pigeonsmust be shown the position of the basket and befed there. Then, on being released rom the loft, they take a directcourse o the basket o be fed. Their messages ay then be removedand new onesplaced n the container and on release hey fly back tothe loft. So stereotypedand unvarying is the pigeon'sbehavior that,in the early stagesof this training, before hey have earned o correlatethe basket with food, they will not fly to it, although t is in full viewof the loft and bears evidence of food, unlessthey are first carried tothat position and fed there. This system of messagecarrying hasgiven very good results; the birds behave faithfully and do excellentservice, slightly slower on the homeward journey when they are


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296 ,co, HomingbilityfCarrierigeon [AukAprilcarryingone-sixteenth f their weight n corn. The chief disadvantagefrom the army point of view is that one point, the loft, must be staticalthough the secondpoint can be altered at will.

)I$CU$$IOlXlThe descent f the modernhomingpigeon rom the wild rock-dovehas already been mentioned and the arbitrary statement made thatits homing ability is at least equal to that of the wild stock; it mayeven be conjectured hat it has been augmented by selection,but ofthis there is no real proof. It is furthermore easonable o postulatethat the homing ability of the rock-doveand, part passu, he homing

pigeon, s, at least in part, of the samenature as that possessedy allmigratory birds. For purposes f discussionhe migratory achieve-ments of birds may be distinguished s follows:1. The initial flights of birds of the year to winter quarters whichthey have never seen before and over routes which they aretraversing for the first time.2. Secondand successivelights of older birds to winter quartersand the return of all membersof the species o summer breedinggrounds.It is obvious rom the nature of its training and the character of itsachievements hat the homing pigeon will not assist n throwing lighton the first problem. It is only within the limits of the second hat asuitable comparisonmay be made. In both cases he birds are flyingto localities which have been seen at least once before; in both casesflight is possibleover routes which have been traversedat least once.The whole training of the pigeon is visual. The position of its loftbecomes horoughly known. In its exercise lights it traversesmany

miles of the surrounding errain. Its tosses re gradually steppedup,mile upon mile, with each toss dovetailing that which preceded t,and with repetition the route becomesbetter known and the time ofreturn is shortened. The birds become ost or will not fly at all underadverse visual conditions. When special training is undertaken totrain birds to fly at night, such training must be done again in easystagesso that the birds are afforded the opportunity of learning suchvisual guidesas may be apparent in dim light. And, in the latter case,the loft is treated so that it may more readily be seen n the darkness.The pigeon ends to follow low groundand valleys where vision s lessrestricted. Finally, when the bird is required to fly over both direc-tions of the route, both termini must be known to the bird by detailedtraining.


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Vol. 62'[1945 NICOL,omingbility fCarrierigeon 297Nothing in such training programsas the army employsor in thecharacterof the flights required of the pigeon eads us to believe that

any senseother than vision is employedby the bird in proceeding rompoint A to point B. Even negativeevidence ffordedby casesof no,or late, return emphasizes his conclusion as in the case of mobile-trained birds when the presentation of a choicebetween old and newflight routes and loft sitesmay lead the bird astray. This visual com-ponent of homing or migratory instinct--the memory of perceivedlocalities--is the only componentwhich need be evoked to explainthe phenomenaso far discussed nd by the rule of economyof hy-pothesis t is reasonable o apply it to the secondof these migratoryflights of wild birds described n this section. In brief, migratorybirds are guided by landmarkswhich they have previouslyseenwhenpursuinga course raversedon one or more earlier occasions.Suitablecomparisonmay also be made with those numerous cases n whichwild birds have been removed varying distances rom their nestingsites and have successfullyeturned home. The destinationof itsflight, as in the caseof the homingpigeon,can be recognized y thebird and in its previouswanderingst may have seenpart of the route.Recognition must now be given to casesof long-distance lights.In training for such aces, ossesmay be given up to 250 miles, but inthe race itself, the bird may be taken many hundreds of miles andthus be releasedover territory which it has never encountered n itsexperience. Part of the route may even lie over featurelesswater.Lossesare considerablygreater in such ong races and birds may begreatly delayed. Comparisonmay be made with the analagouscaseafforded by the experimentsof Watson and Lashley (4) in whichNoddy and Sooty Terns were removed from nesting sites on theTortugas Islands in the Gulf of Mexico and carried for distancesofmore than 850 miles northward into areas n which these spedesarenot normally found. These birds hornedsuccessfully ver water andmemory of landmarks could have played no part in accomplishingthat flight.In conclusion, t may be stated that the homing pigeon normallyutilizes landmarks which it has seen before to guide it on its course.But it can alsosuccessfully ome for long distances ver routeswhichare strange to the bird. And in such cases so-called inheritedmemory can play no part since the route followed is selectedar-bitrarily by man. Su_

l. Carrier pigeons can be trained to fly to loft sites which arefrequently changedat intervals of three to sevendays.


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fAuk298 N,co, omingbilityfCarrierigeon tgpril2. They can be trained to fly short distances t night.3. By placing he loft at one point and feeding he birds at another,

carrier pigeonscan be made to fly over both directions of a route.4. The pigeon utilizes visual aids in its flight. and all trainingemphasizes his factor.5. Homing flights of pigeonsmay be compared to those migratoryflights of wild birds which are proceeding o destinationspreviouslyvisited over routes traversed on one or more earlier occasions.6. In long-distance races, pigeons are released at considerabledistancesbeyond the point of their last training toss and are conse-quently compelledto home over territory new to their experience.

Inherited memory can play no part in suchflights since he route,selectedarbitrarily, bears no relation to the flight habits of its wildancestry. SOURCES

In the preparation of this paper the writer has drawn upon six-months' experiencewith the pigeon service in the Canadian Army,has watched the experimentscarried out by British Army personnel,and has consulted the official instructions of the Canadian and Britisharmiesand the Royal Canadian Air Force. In addition, referencehasbeen made to the following publications.I. DARWIN, CHARLES1859. The Origin of Speciesby Means of Natural Selection. The Variation ofAnimals and Plants under Domestication.2. OSMAN,LIEUT.-CoL. A. H.Pigeons n the Great War. ( The Racing Pigeon Publishing Co. Ltd.,London.)3. PmsY, R. E.192 . The SignalService n the EuropeanWar of 1914 o 1918 France). (W. andJ. MacKay and Co., Ltd., Chatham.)4. WATSON,J. B., AND LASHLE,K. S.1915. Homing and Related Activities of Birds. (Washington.)SecondCanadian CorpsSignalsCanadianArmy Overseas

nicol - homing ability of carrier pigeon

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