THEAUK

A QUARTERLY JOURNAL OF

ORNITHOLOGY
VOL. 79
THE

STATUS

JULY, 1962
OF LARUSGULLSRELICTUS
FROMANDCENTRAL

No. 3
OF OTHERHOODEDASIACHARLES VAURIE

Os 24 April 1929 a singlespecimenof a strangehoodedgull was collectedby K. G. S6derbom,
a memberof SvenHedin'sexpeditionto eastern
centralAsia,at Tsondol,a remotelocalityon the Etsin Col [River] innorthernInner Mongolia. Accordingto L6nnberg (1931a), Tsondol issituatedat 41ø 53' 30" N by 101ø 6' 33" E, or not far from SogoNor[Lake], calledalsoSochaNor on somemaps,oneof severallakesinto
whichthe Etsin empties.All theselocalitiesare in the provinceof Ningsia,
the westernmost
politicaldivisionof Inner Mongolia,in the southernpartof the Gobi Desert.

This specimen,
whichI haveexamined,is an adult hoodedgull in breeding plumage,sex unknown. I believeit is a hybrid of Larus ichthyaetus(Great Black-headedGull) and L. brunnicephalus(Brown-headedGull),but L6nnberg (1931b) has named it Larus melanocephalus
relictus, believingthat it probablyrepresents
an individualof a relict and undescribed
race of the MediterraneanBlack-headed

Gull.

The only other authorswho seemto have discussed
the statusof relictus

are Dementiev (1951: 525) and Mayaud (1956: 131). They did not
examinethe specimen
fromMongolia,but Dementievrejectsthe possibility
that it is a form of melanocephalus,suggestingthat it is an aberrant
specimenof brunnicephalus
misidentifiedby L6nnberg. Dementievmakes
also the relevant observationthat no other specimenof rellctushas beenfoundalthoughMongoliahas been well collected.Mayaud merely comments on the remarks made by Dementiev, stating that Dementiev's
hypothesisis very unlikely ("bien peu vraisemblable")and that it is best
to admit provisionallythat relictusis a very big melanocephalus,
the rangeof which needs to be determined.

It is difficult to agreewith Mayaud and L6nnberg. The latter (1931b)
statesthat relictus"appearsto resembleLarusmelanocephalus
morenearly
than any other species." But relictus resemblesmelanocephalus
only to303

The Auk, 79: 303-309. July, 1962

Heads(top to bottom)of LarusmelanocephaluJ,%'elictns,"
and brunnicephalus.The specimens
areadultsin breedingplumageandwerepaintedexactlyas they are. But, in living birds during the breedingseason,the bill of
melanocephalus
is red with a slight duskysubterminal
band, and that ofb•wnnicephalus
is deepred.

304

V^umE,
Statuso!HoodedGulls
TABLE

79
[ Vol.^uk

1

MEASURE/V[ENTSOF SO/VIEHOODED GULLS1(in mm)Form
rellctus

Wing2
340

mlnutus217-232 (226.2)
melanocephalus 290-317 (300.7)
ridibundus
286-308 (298.6)
brunnicephalus 322-352 (337.1)
ichthyaetus
451-507 (480.7)

Tail
123

82-92 (87.7)
99-119 (111.3)
102-117 (111.6)
122-134 (126.5)
164-200 (180.8)

Bill3

Tarsus53

28-34 (31.6)
42-49 (44.5)
42-47 (45)50-58 (53.5)
76-95 (83.2)

59

22-28 (25)44-50 (46.9)
40-45 (42.8)
47-54 (50.3)
69-83 (75.2)

XThe sex of the type of relictus,an adult, is unknown; the measurementsof theother gulls are those of 10 adults consistingof five males and five females.
2 Flat wing.
s Measured from the skull.

the extent that the posteriorpart of its hoodis black (cf. frontispiece);moreover,the blackarea is dullerin relictus,not sopure and deepblackas in melanocephalus.
The wing patternsof relictusand melanocephalus
are totally different(Figure 1), and relictusis a muchbiggerbird'(Table1). As is clearlyshownby LSnnberg's
photograph,its tarsusgivesthe impressionof beingnearly twice as big.
The theorythat relictusrepresents
a relictpopulationof melanocephalus
presupposesthat the rangeof this gull was oncemoreor lesscontinuousfrom the Mediterraneanto the Gobi. But, at present,the nearestcolonyof melanocephalus
is found at the westernend of the Sea of Azov, 5,500
km from the Gobi. Melanocephalus
breedson the Black and the Aegeanseas and is not highly migratory, remainingon or near the breeding
groundsor migratingto the Adriatic and centralMediterranean,the latter
formingthe main winter quarters. A few individualswanderinland in awestward

direction to reach the Baltic and North

seas.

The TethysSeais ofteninvokedto explainthe present-daydistributionof many animals,but its extensions
into Asia occurredfar too longago to
be relevantto ourproblem.At the time of its greatestnorthwardextension
duringthe middleand upperCretaceous,
it reachedalmostto the Aral Sea(cf. Ekman, 1953, Figure 23), and, farther east, via a separatetongue
throughwhat is now Ferghana,to the Tarim Basin,where,accordingto
Norin (1941), it lingeredthroughoutthe Eocene. The oldestgull fossil
known is more recent, dating to the Oligocene(Storer, 1960), but mostgull fossilsdate only to the Mioceneor later. I may add that Stegmann(1938), whohasdiscussed
the affinitiesof the Mongolianavifauna,denies
categoricallythat it has been derivedfrom the Mediterranean.In short,
it seemsmostunlikelythat relictusis a form of melanocephalus.
Mongoliais remote,but, as notedabove,the birdsof this regionand ofneighboring
westernChinahavebeenwell collected.Kozlova( 1930, 1932)
givesa shortsummaryof 10 expeditions(not includingthat of SSderbom)

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305

306V^um•, Statusof HoodedGulls[[ Vol.
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79

that coveredtheseregions. Meise (in Stresemann,Meise, and SchiSnwetter,1937) mentions eight additional expeditions. At least two collectors(Kozlov in 1908 and Beick at the end of 1932 and beginningof 1933)
have collectedalong the lower Etsin River for periods of about threemonths. It is remarkable,therefore,that no other relictushas been found,and this suggeststhat the bird taken by SiSderbom
is indeedan aberrant
specimen,a possibilitythat was not contemplatedby LiSnnberg.
If it is a hybrid, as I believe,a searchfor its putative parentsmust be
narrowed to the hooded gulls that breed or migrate through Inner andOuter Mongolia and the neighboringregionsof China. These are four,
two with black hoods (ichthyaetus and minutus) and two with brownhoods(brunnicephalusand ridibundus). The Little Gull (minutus) is sotiny in every respect that it seemsto be eliminated from consideration;
moreover,its primaries are bluish-gray above, unlike those of the othergulls. But the colorof the hoodin relictus (cf. frontispiece)suggeststhat
this bird is the offspring of a black-hoodedgull that had bred with abrown-hoodedone, and the only other black-hoodedgull in the regions
under considerationis ichthyaetus. The latter is not shown in the frontispiece, but its hood is identical with that of melanocephalus(which isshown) in color and extent, the only differencebeing that the white eye
patchesare more developedin ichthyaetus,actually as well as proportionately, and thus are similar to thoseof relictus.
Larus ichthyaetusis a very big gull (Table 1), and, at first, it is difficult to believethat it would mate with one of the other two considerably
smallerbrown-hoodedgulls. Nevertheless,the similarity betweenthe wing
pattern of ichthyaetusand relictus (Figure 1) is extremelysuggestive,
thepatterns of the third and fourth primaries (counting from the outside)
being virtually identical. The wing pattern of ichthyaetusshownin Figure
1 is about average,but someindividualsare whiter on the inner web of thefirst and secondprimaries and thus are even more similar to relictus, theblack pigment falling far short of the outer margin of the web. The tarsusof relictus is also much longer, and considerablyheavier and thicker thanthat of brunnicephalus,the bigger of the two brown-hoodedgulls; it isnearly intermediate in size between that of the latter and ichthyaetus.
The lengthsof the wing, tail, and bill of relictus and brunnicephalusare
similar, but it is of interest to note that the shape of the bill of relictus
is similar to that of ichthyaetus,strongerand higher, and less slender,
than in brunnicephalus.The intermediatecolorationof the anterior partof the hood is obvious,but the white eye patchesof relictusare big and,as noted, are similar to thoseof ichthyaetus.
All thesecharacterssuggestvery strongly that ichthyaetuswas one ofthe parents. But it is more difficult to determinethe identity of the brown-

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V^uRm, Status o] Hooded Gulls

307

hoodedparent. The breeding range of ichthyaetus overlapsthat of ridibundusand brunnicephalus,but I believe the latter was probably theparent with the brown hood. It is considerablybigger than ridibundus(mistakenlycalled Black-headedGull), has a much more pigmentedwing,
and its hood is mixed with black posteriorly. In ridibundus the brownhoodis concolorous.The systematicrelationshipsof ridibundusand brunnicephalusare discussed
below.
One characterof the hybrid that is not presentin any of the other gulls
mentionedis the great developmentof its hood. The pigment (cf. frontispiece) extendsto the hind neck and onto the upper breast, and I havesatisfiedmyself, as did L/Snnberg,that this is not an artifact causedby themakeup of the skin. This posteriorextensionof the hood appearsto bea "primitive" character,lost in the hoodedgulls of Mongolia but retainedin the two gulls of the Red Sea (hemprichiiand leucophthalmus),which
are generallyregardedas the most primitive speciesamong the hoodedgulls. Perhapsmodifierscontrol this characterin the gulls of Mongolia
but were not effectivein the hybrid.
The two brown-hoodedgulls of Mongolia and western China are undoubtedlyseparatespeciesand were placedin different subgenera(brun-nicephalusin Cirhocephalaand ridibundusin Hydrocoleus)by Dwight(1925). It is doubtful that anyonewould follow Dwight today, but totreat them as subspecies,
as Stegmann(1935) would have us do, seems
equally extremein the oppositedirection. Note shouldbe taken also ofMoynihan's (1959) misleadingstatementthat "Stegmann (1935) has
shownthat [brunnicephalusand ridibundus]interbreedwheretheir ranges
meet"; Moynihan followsStegmannin treating them as subspecies.ButStegmannhas not shownthat thesetwo gulls interbreedregularly or that
their rangesmeet. All that Stegrnanndid was to report five specimensfrom Sinkiang,which he believedwere hybrids of these two gulls, and,apparentlymisinterpretingthe breedingrangeof the two species,
to statethat thesehybridsshowthat "we must recognize"that the two gulls areconspecific.

Hybridizationdoesnot provethat two formsare conspecific,
and interspecifichybridsare far from unknownamonggulls. Hybridsof fuscusand
glaucoides
and of marinusand hyperboreus
have been reportedby L/Snnberg (1919); fuscusand argentatusinterbreedoccasionally(seealsoTinbergen,1953); melanocephalus
wandersoccasionallyto the North Sea
and mixed pairs of this gull and ridibundushave been reportedfrom theNetherlandsby Vijverberg (1935); 11 speciesare involved in the long
list of hybridsof the genusLarus publishedby Gray (1958), and of theseridibunduswas the parentin five instances,althoughthesewerenot "wild"
hybrids; finally, witness"relictus,"the main subjectof this paper.

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V^umE, Status o! Hooded Gulls[[ Vol.
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The knownbreedingrangeof ridibundusin high centralAsia consistsof
Tannu Tuva, and, accordingto Kozlova (1932), the lakes and rivers ofnorthwesternand northernOuter Mongolia; to my knowledge,it hasneverbeenreportedto breedin ChineseTurkestan. Brunnicephalus
breedsfrom
the Kun Lun and easternTsinghai (and probably also Kansu), south to
the Pamirs and the Tibetan Plateau. In other words, the known breeding
rangesof these two gulls are widely separated. There is no evidenceto
supportthe statementmade by Stegrnann(1935) that ridibundusbreeds"throughoutTurkestan and Mongolia" and that its breedingrangeborders("aneinandergrenzen")on that of brunnicephalus,or that the breeding
ranges"meet" as interpretedby Moynihan (1959).
It is possible,however, that some individuals wander far from theirnormal breedingrange, and, lacking a mate of their own species,interbreed, a case that would parallel the interbreeding of ridibundus andmelanocephalus
in the Netherlandsreportedby Vijverberg (1935). Perhaps, the parentsof the hybrids reportedby Stegmannpaired on theirwinter grounds,namely in India, which forms a part of the regular wintergrounds of ridibundus and brunnicephalus,and, I may add, also ofichthyaetus.

The morphologicaldifferences
betweenridibundusand brunnicephalus
are very sharp and have been mentionedabove. The differencebetween
the colorof the primariesis striking (Figure 1), and, from a phylogenetic
point of view, it seemssignificantto me that this differenceexistsalsoin
the juvenalplumage. Indeed,the wing tip is wholly black in youngbrunnicephalus,whereasit is predominantlywhite in young ridibundus.
ACKNOWLEDGMENTS

This study was started in the Naturhistoriska Riksmuseumof Stockholm and the British Museum (Natural History) of London, and I takepleasurein expressinghere my gratitude to A. Johnelsand G. Rudebeckof Stockholm,and J. D. Macdonaldof London, for their cooperationand
friendly receptionat their museums;Dr. Johnelshad the further kindness
to lendme the specimenof relictusin orderthat it mightbe comparedwith
the very large seriesof gulls in the British Museum. I am grateful also
to Miss Chloi/ Talbott Kelly for her fine color plate painted under mydirectionin London,and to my colleagueshere at the AmericanMuseum of
Natural History, namelyD. Amadon,E. Eisenmann,and M. C. McKenna,
for reading and commentingon the manuscript. My visit to European
museumsin 1961 was financedby grant G15917 from the National ScienceFoundation, which I gratefully acknowledge. I am indebted also to theMae P. Smith Fund of the American Museum of Natural History formeetingthe costof the colorplate.

^uk ]V^[-mE,Status of Hooded Gulls

Vol. 79 J309

SUMMARY

An adult hoodedgull from Mongolia is discussed.It is known from asingle specimenthat had been describedby LiSnnbergas a subspecies(whichhe namedrelictus) of Larus melanocephalus,
but the specimenappearsto be a hybrid of L. ichthyaetusand L. brunnicephalus.The otherhoodedgullsbreedingin or migratingthroughhigh central Asia are considered,and it is emphasizedthat brunnicephalus
and ridibundusare probably separatespeciesalthough some authors considerthem to be conspecific.
LITERATURE CITED

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SovietskogoSoiuza, 3: 372-603.
DWm•T, J. 1925. The gulls (Laridae) of the world. Bull. Amer. Mus. Nat. Hist.,
52:63401.

EKM^•, S. 1953. Zoogeographyof the sea. Sidgwickand JacksonLtd., London.
GRAY, A. P. 1958. Bird hybrids. Commonwealth Agricultural Bureaux, Farnham
Royal, Bucks, England.

Koz•ov^, E.V.

1930. Ptitsy iugo-zapadnogoZabaikalia, severn.9iMongolii, i tsen-tralnoi Gobi. Material. Komiss. Issled. Mongol. i Tuvinsk. Narodnikh Respublik
i Buriat-Mongol. ASSR, 12: 7-13.

Kozrov^, E. V. 1932. The birds of south-west Transbaikalia, northern Mongolia,
and central Gobi, pts. 1 and 3. Ibis 319-323, 583-584.
L6•RG,E. 1919. Hybrid gulls. Arkiv fiSr Zool., 12(7): 1-22.
L6•R½,E. 1931a. A contribution to the bird fauna of southern Gobi. Arkiv
fiSr Zool., 23A(12): 1-18.
L6•E•½,E. 1931b. A remarkable gull from the Gobi Desert. Arkiv f6r Zool.,
23B(2): 1-5.
M^¾^xm, N. 1956. Nouvelles donndessur Larus melanocephalusTemminck. Alauda,
24:123-131.

M•s•, W. 1937. In E. Stresemann,W. Meise, and Schi3nwetter,Aves. Beickianae.
J. f. Orn., 85: 426434.
MoYm•^•, M. 1959. A revision of the family Laridae (Aves). Amer. Mus. Novirates, no. 1928, 14.

Noah,, E. 1941. In K. Andr•e, H. A. Brouwer, and W. H. Bucher (ed.), Regionale
Geologieder Erde, 2, pt. 4b: 1-36.
Sx•g•vr^•, B. 1935. Die systematischeStellung der tibetanischen Lachmi3we (LarusbrunnicephalusJerd.). Orn. Monatschr., 43: 77-82.
ST•g•vr^•, B. 1938. Osnovy ornitogeografisheskogodeleniya palearktiki. Fauna
S.S.S.R., Nov. Ser. no. 19, 1, no. 2, Akademii Nauk SSSR, Moskva, Leningrad.
STOV,•a,R. W. 1960. The classificationof birds. In A. J. Marshall (ed.), Biology
and comparative physiology of birds. Academic Press, New York and London.
T•ragr•,N. 1953. The Herring GulFs world. Collins, London. xvi q- 255 pp.
V•jv•a•Eag, J. 1935. Larus melanocephalus Ternre. broodvogel in Nederland(Schouwen). Ardea, 24: 260-261.

The AmericanMuseum o/Natural History, New York 24, New York.