56 JOUNSON,Status ofthe "White-eyed" ]V[urre [Jan.Auk STATUS OF THE "WHITE-EYED" MURRE' BY ROBERT A. JOItNSON Plate 5 THE systematicposition of the "White-eyed" Murre (Uria aalgeaalge), has long been a controversialissue. Birds with a white line of feathers aroundthe eye and a white streak extendingbackward along the postocular groovecalled "white-eyed," "ringed," "spectacled,"or "bridled" Murres, were noted by early travelerswho wrote about sea-birdcolonies and were then, as they are today by some observers,considered a different species from the birds not so marked. Thesestriking birds occurthroughout the range of the typically colored members of the Common Murre, Uria aalgeaalge (Pontoppidan). From time to time specificrank has been officiallyaccorded them, althoughat presentthey are not generallyad- mitted to such distinction. Neverthelessthe questionhas neither been dropped nor satisfactorily settled. Recent writers (Oberholser, 1920; Ridgway, 1919) expressthe belief that the bird shouldagain be given specificrecognition. The problemis of specialinterest to ornithologists, and is alsoa significantone from the point of view of generalbiology. In discussingthis problem,A. C. Bent (1919),presented some of the con- flictingevidence and left the caseundecided, although he seemsinclined to regardit as a species.He writes:"Mr. William Brewster(1883), Dr. Louis Bishop (1889), and Mr. C. J. Maynard (1896) all reportedthis bird in mated pairs on Bird Rock and suggestedthat it is entitled to specificrank. On my visit to Bird Rock in 1915, elevenRinged Murres werenoted in a groupby themselves.Dr. Townsend,the sameseason, saw about fifteen togetherin oneplace, on the southcoast of Labrador,all belongingto this form." Oberholser(1920) proposedUria ringviafor the forthcomingA. O. U. Check-list,but in 1924,before the publicationof the Checkdist, dropped the suggestion.Ridgway (1919) had used the name Uria ringvla and Ogilvie-Grant,in the 'Catalogueof the Birdsof the BritishMuseum' (1898), liststhe form as a variety. McWilliam (1930) has summarizedthe discus- sionfrom the Europeanpoint of view. He callsattention to the European recordswhich show that thesewhite-eyed birds occur much more commonly among the northern British breedingcolonies than they do among the southernBritish colonies. He says: "I do not know of any colony in Britain where it is entirely absentand, on the other hand, there is no colonyknown where it aloneis found." :FromUssher and Warren'sinterest- • This study is part of a thesis for the DeI)•rtment of Ornithology, Cornell University. It was read before The Arneriean Ornithologists' Union at the Toronto meeting, October 1935. .I Vol..55]1938 I JoaNsoN,Status ofthe "White-eyed" Murre 57 ing book, 'The Birdsof Ireland,' we learnthat the White-eyedMurre occurs in all coloniesof the species,but scarcelyone white-eyed to fifty of the ordi- nary type, and that the white-eyedare nevergrouped together. On the Isle of Man little is known about thesebirds except that a few havebeen seen amongordinary birds on SpanishHead. In North Walesone seldom meets with them. One report givesone White-eyedMurre to two or three hun- dred of the ordinary type. In West Scotland,a count of over 1500 dead birdsdisclosed the presenceof two of this kind. Grey estimatesthat there is only one white-eyedbird to five hundredof the others. In the Hebrides where the Northern Murre breeds they are much more common. The birdsof Scotlandand Wales are, I believe,generally considered to be of the southernBritish form. A censusmade in the Outer Hebridesin 1871 by Feilden and Hatvie-Brown gives 24 of the white-eyedindividuals among 126 birds. Harvie-Brown states that from statisticscollected over many years,one to five is about the averagein the Outer Hebrides. Dr. Harrison F. Lewis (1926) has shownfrom his bandingrecords in 1925that about 15.7 per cent of the birds breedingalong the north shoreof the Gulf of St. Lawrencebelong to this type, and he alsorecapturea two of theseindividuals, marked in a previousyear, which had retainedthe same character. Later, with a larger number available for the year 1929, he found (Lewis, 1930) 128 out of a total of 724 adult CommonMurres, or 15.7 per cent of white-eyedindividuals. He notedthat thesewere "well scatteredamong the other CommonMurres; somebeing presentin every breedingcolony." In one groupof fifty birds capturedthere were eight white-eyed ones. Thuswe haveindicated a few of the moreimportant reports in the litera- ture bearingon this discussion.Most observersof sea-birdcolonies do not seem to realize the unnatural conditionwhich their presencemay cause amongthe birds,both in behaviorand in the distributionwithin the colonies. A few observersin Europe and alsoin Americahave seena white-eyedand a typicalbird pairedtogether. Several other observers seem'to think that this is not the case,so that we have many conflictingdeductions resulting from little reliable evidence. Regardingthe relative numbersof White-eyedMumes in different parts of the range, the countswhich have been reportedare very interesting. From these, perhaps,we may approximatethe relative distribution as follows:in North America16 per cent,in the Hebrides25 to 30 per cent, in southernBritish watersless than 1 per cent, and in the Bear Island region from 30 to 50 per cent. During two summersof field observationswhich took me to most of the largebreeding colonies along the north shoreof the Gulf of St. Lawrence, I have gatheredconsiderable data pertainingto these birds which, with 58 JOHNSON,Status of the "White-eyed" Murre [Jan.[Auk other material suppliedlargely by Dr. Lewis, I believe is ample to show that this form, Uria ringvia, has no claim to specificdistinction. My findingsare presentedin summary form as follows: 1. The white-eyedindividuals of the Atlantic Murre mate with normal or typicallycolored birds more often than with oneanother. Of five mated pairs that I have studied at some length from a blind, four were mixed matings;that is, a white-eyedindividual was mated with a typical bird. White-eyedbirds seen courting on the rockshave most often been involved with a typical bird. Clearly the matingsare purely random. 2. The white-eyed birds are on the whole fairly evenly distributed throughoutthe nestingcolonies. I have never seenany indicationof their groupingtogether although it is not uncommonto seethree or morein close proximity within a colony. 3. The eggsbelonging to pairs which involve one or more white-eyed birds exhibit the normal range of color types. However, I have not been ableby sexingbirds to determinethat a givenegg was produced by a white- eyed female in more than one case. This egg was of the blue-greencolor type. On this point many reportsare conflicting. But, sincewe now know that in the caseof the Murre, the sexesalternate in the performanceof the incubation duties, and that the sexescannot be distinguishedby sight, it seemscertain that most of the observerswho have reportedon the colorof the egg of ringvia shouldhave been uncertain about the egg reported belongingto such a female. It might just as well have been a caseof a white-eyedmale tending the egg of his mate, a typically coloredfemale. More definite data regardingthe color of eggsof known parentageare desirable. 4. Youngbirds with oneor two white-eyedparents are indistinguishable from all the others at hatching and up to the time when they leave the nestingislands at approximatelythree weeksof age. Experiments with young birds taken when ready to leave the islandsand kept in captivity, indicatethat the characterof the juvenal plumageis clearly observable beforethey leave the nestingcolonies. This leadsme to believethat the white-eyedcharacter does not becomeapparent until the adult plumage is developed.I havefound no signsof it in theseyoung and juvenalbirds. 5. Dr. Lewishas shownthrough his bandingactivities that adult breed- ing birds with the white-eyed characteristicretain it from one year to another. 6. The white-eyed adult individuals are representativeof Uria aalg• aalgein showingthe normalvariations in sizeand measurements. 'Vol.1938 55]J JOHNSON,Status ofthe "White-eyed" Murre 59 CONCLUSIONS The foregoingevidence seems to settlethe questionof specificdistinction but leavesus with the moreinteresting question, What is the explanationof this white-eyedcharacter? My belief is that we have here a hereditary characteristicoperating as a recessive.Whether it is due to the operation of one geneor to the collectiveinfluence of more than one, I do not know, but I shouldnot be surprisedif it werefound to be due to a singlegene. If there is absolutelyrandom mating and the characterdoes not tend to be lethal, the proportionof white-eyedbirds in any population would eventuallyreach an equilibriumanywhere from lessthan one in five hun- dred to a very high percentage.This, in fact, seemsto be the actual con- ditionin differentparts of the rangeof the species.Accepting this theory, other interestingobservations might be made. The relatively small per- centageof white-eyed•Vfurres reported in southernBritish breeding colonies is goodevidence that there is not much, if any, interminglingbetween the southernbirds namedby Witherby, in 1925, Uria aalgealbionis and the northernform, Uria aalgeaalge. In fact, this very discrepancyfound in the differentgeographical areas does, I believe,give weight to the ideathat they are segregatedbreeding populations. Why the white-eyedbirds are rare in the southernBritish breeding populations is anotherquestion. From the literatureon