Table Of ContentPROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASfflNGTON
109(4):755-763. 1996
Diagnoses of hybrid hummingbirds (Aves: Trochihdae). 1.
Characterization of Calypte anna x Stellula calliope and the possible
effects of egg volume on hybridization potential
Gary R. Graves and Nancy L. Newfield
(GRG) Department of Vertebrate Zoology, National Museum of Natural History,
Washington, D.C. 20560, U.S.A.; (NLN) Casa Colibri, 3016 45th Street,
Metairie, Louisiana 70001, U.S.A.
—
Abstract. Plumage pattern, plumage color, and external morphology oftwo
specimens of hybrid hummingbird {Calypte anna X Stellula calliope) are de-
scribed. The parental species differ substantially in size, and the hybrids are
similar to the averages of character means of the parental species. Expression
of parental plumage characters in the hybrids varies, particularly the color and
configuration ofthe frontlet and gorget. The possible effects ofegg volume on
hybridization potential are discussed.
The possibility of hybridization among Sierra San Pedro Martir (7500 ft elevation
North American species of hummingbirds [2287 m]), Baja Cahfomia del Norte, Mex-
(Trochilidae) was mentioned by Jeffries as ico. Grinnell (1928:134) noted that Lamb's
early as 1888. The first published notice of specimen (Museum of Vertebrate Zoology
such hybridization was buried in Fisher's [MVZ], University of California No.
monograph on Death Valley birds (1893), 47983; 3.1 g), ". . . shows hybrid origin,
and Suchetet (1896) did not list any hybrid apparently Stellula calliope X Calypte
Trochilidae in his review of avian hybrids. anna,'' but left Berlioz (1930) to describe
Subsequently, a few ad&ditional cases were it formally. Three decades later. Banks &
reported (e.g., Thayer Bangs 1907, Ber- Johnson (1961) reexamined the specimen
&
lioz 1930), but Banks Johnson (1961) and elaborated on Berlioz's description.
were the first to evaluate critically the Neither Berlioz nor Banks and Johnson dis-
known hummingbird hybrids from North
cussed alternative parental hypotheses.
America. The latter authors, in an exempla- A second hybrid hummingbird, also pos-
ry study that set the standard for future sibly Calypte anna X Stellula calliope, re-
work on this subject, documented five hy-
cently was collected by Newfield in Baton
brid combinations based upon the direct ex-
Rouge, Louisiana, on 22 December 1993
amination of specimens and noted three
(Louisiana State University Museum of
other probable combinations for which they
Natural Science, Louisiana State University
were unable to locate the pertinent speci-
mens. Additional hybrids were reported by (LSUMZ) No. 154189; testes minute, skull
Short & Phillips (1967), Lynch & Ames 10% ossified, light neck molt, 3.7 g, light
(1970), Wells et al. (1978), and Newfield fat, insect parts in stomach, frozen tissue
(1983). To date, a total of 13 hybrid com- saved (B-19447), prepared by Steven W.
binations (Table 1) have been documented Cardiff).
by specimens among the hummingbird spe- Here we present ahybrid diagnosis ofthe
cies that regularly breed north of Mexico. two specimens and discuss the field iden-
On 19 June 1926, Chester C. Lamb col- tification of hummingbird hybrids. Finally,
lected an adult male hummingbird in the we briefly address the possible constraints
756 PROCEEDINGS OFTHE BIOLOGICAL SOCIETY OF WASfflNGTON
—
Table I. Hybrids reported among species ofhummingbirds that breed north ofthe Mexican-U.S.A. border.
References indicate the earhest publication ofthe identification ofhybrid parentage that is currently accepted.
Hybridcombination References
Amazilia violiceps x Cynanthus latirostris Griscom 1934
Archilochus alexandri x Calypte anna^ Thayer and Bangs 1907
Archilochus alexandri x Calypte costae Fisher 1893
Archilochus alexandri x Selasphorusplatycercus^ Banks and Johnson 1961
Archilochus alexandri x Selasphorus sasin Lynch and Ames 1970
Calypte anna x Calypte costae Wells et al. 1978
Calypte anna x Selasphorus sasin^ Thayer and Bangs 1907
Calypte anna x Stellula calliope^ Grinnell 1928
Calypte costae x Selasphorusplatycercus Huey 1944
Calypte costae x Stellula calliope'^ Hartert 1900
Cynanthus latirostris x Eugenesfulgens Short and Phillips 1966
Selasphorus rufus x Stellula calliope Thayer and Bangs 1907
Selasphorus rufus x Selasphorus sasin Newfield 1983
Specimens examined by Banks and Johnson (1961).
on hybridization imposed by interspecific plots of size variables to display morpho-
differences in egg volume. logical variation in two dimensions.
For purposes of the hybrid diagnosis, we
Materials and Methods used the methodological assumptions out-
lined by Graves (1990). The hybrid diag-
For the hybrid diagnosis, we considered noses followed a two-step procedure. First
the geographic pool (sensu Graves 1990) the presumed parental species of each hy-
from which potentially hybridizing species brid were hypothesized through compara-
may be drawn to include all hummingbird tive analysis of plumage pattern and color.
species (« = 15) that breed regularly north These hypotheses were then examined with
of Mexico or in Baja California del Norte quantitative analyses of external measure-
(AOU 1983, see Appendix 1). Neither of ments. Concordance of results is regarded
the putative hybrid specimens possesses as strong support for the presumed parent-
striations or corrugations on the upper age of the hybrids (Graves 1990, Graves &
rhamphotheca (Ortiz-Crespo 1972), indicat- Zusi 1990).
ing that both birds were "adult." The hy-
brids (hereafter referred to as "Baja" or
Results
"Louisiana" hybrids) were compared with —
large series of adult males of all North Plumage characters. Neither putative
American species of hummingbirds in the hybrid specimen can be assigned to any
National Museum of Natural History known taxon of hummingbird, even after
(USNM), Smithsonian Institution. Plumage considering the possibility of plumage ab-
color was evaluated under Examolites errancy due to mutation or environmental
(MacBeth Corp.). Measurements of wing induction. Both specimens possess a dis-
chord, lengths of the first (central), third, tinctive combination of characters that can
and fifth rectrices (from point of insertion be found among the assemblage of species
of central rectrices), greatest widths of the in the geographic pool (Appendix 1), but
first, third, and fifth rectrices, and bill not in a single species, which itself is evi-
length (from anterior edge of nasal flange) dence suggestive of hybridization. Three
were made with digital calipers to the near- characters of the hybrids permit their pa-
est 0.1 mm (Table 2). We used bivariate rental species to be identified: (1) abrilliant.
VOLUME 109, NUMBER4 757
—
Table 2. Ranges and means (± one standard deviation) ofmeasurements (mm) ofadultmale Calypteanna,
Stellula calliope, and their male hybrids (MVZ 47983, LSUMZ 154189).
Hybrids
Calypteanna Stellulacalliope
Character (n = 12) (n = 12) MVZ LSUMZ
Wing chord 47.9-51.0 38.0-40.7 44.3 43.6
49.3 ± 1.0 39.2 ± 0.8
Bill length 17.4-19.4 13.1-15.1 16.4 16.8
18.1 ± 0.6 14.0 ± 0.5
Rectrix 1 length 22.9-26.5 17.5-18.7 21.2 20.0
24.5 ± 1.0 18.2 ± 0.4
Rectrix 3 length 26.2-28.5 18.7-20.2 24.5 23.1
27.6 ± 0.7 19.6 ± 0.6
Rectrix 5 length 30.3-32.5 18.2-20.3 25.7 25.8
31.3 ± 0.9 19.3 ± 0.6
Rectrix 1 width 7.6-10.5 4.1-*.9 5.6 5.7
8.9 ± 0.8 4.5 ± 0.2
Rectrix 3 width 5.3-7.4 4.9-5.6 6.1 6.4
6.4 ± 0.6 5.2 ± 0.2
Rectrix 5 width 3.0-3.7 3.4-3.8 3.3 3.6
3.4 ± 0.2 3.6 ± 0.1
contrasting frontlet; (2) parallel or slightly have brilliant frontlets that contrast with the
concave margins of the central rectrices; remainder ofthe capital feather tract in col-
and (3) rufous margins ofrectrices 1, 2, and or and iridescent intensity (the crown but
3 (Figs. 1-3). not the frontlet of Eugenesfulgens is bril-
Only two species in the geographic liant). With the exception ofthe gorget and
source pool, Calypte anna and C. costae. frontlet, the plumage color of C. anna and
.nm
Cahf'^
Fig. 1. Lateral view of adult males, from top to bottom: Stellula calliope; Calypte anna X S. calliope
(LSUMZ 154189); C. anna X S. calliope (MVZ47983); C. anna.
758 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASfflNGTON
Fig. 2. Ventral view of adult males, from top to bottom: Stellula calliope; Calypte anna X S. calliope
(LSUMZ 154189); C. anna X S. calliope (MVZ 47983); C anna.
C. costae is similar, but neither species has rufus or S. sasin were involved (a more de-
rufous pigmentation on the rectrices. This tailed description of the plumage is pre-
means that a species of Calypte is a parent sented in Appendix 2).Amaziliayucatanen-
of both hybrids, but that neither hybrid sis can be rejected as a parental species for
could have been produced by an intrage- several reasons, most notably the color of
neric union (see Wells et al. 1978). its throat, belly, and fleshy rhamphotheca.
Adult males of 5 species in the source Thus, plumage characters suggest that the
pool (Amazilia yucatanensis, Stellula calli- parentage of both hybrids is Calypte sp. X
ope, Selasphorus platycercus, Selasphorus Stellula calliope. —
rufus, Selasphorus sasin) have rufous pig- Mensural characters. Assuming addi-
mentation on the rectrices. Of these, only tive genetic variance (see Graves 1990,
Stellula calliope has subspatulate central 1996), measurements of the hybrids should
rectrices with parallel or concave margins fall within the cumulative ranges observed
(as in the hybrids). Although the Louisiana in large samples ofthe parental species. Ca-
hybrid superficially resembles S. platycer- lypte costae and S. calliope are among the
cus in gorget color, neither it nor the Baja smallest species (body mass, wing length)
hybrid exhibits any evidence of the ex- in the geographic pool. Data in Table 2 and
tremely attenuated outermost primary values for C. costae (Wells et al. 1978), in-
found in males of that species. The hybrids dicate that the length ofrectrix 5 ofthe hy-
C
lack extensively rufous or buffy sides, brids exceeds those of costae and S. cal-
flanks, or rump, as would be expected if S. liope by a minimum of 12% and 27%, re-
VOLUME 109, NUMBER4 759
Fig. 3. Lateral view of Calypte anna X Stellula calliope hybrids: LSUMZ 154189 (top) and MVZ 47983.
Note difference in shape oflateral gorget feathers.
spectively. As morphological luxuriance Discussion
(where a hybrid is larger than either of its —
Field identification of hybrids. Case
parental species) is unknown among tro- histories ofthe two known Calypte anna X
chiline hybrids (Graves, unpubl.), these
Stellula calliope hybrids strongly suggest
comparisons effectively rule out C. costae that the parentage of hybrid hummingbirds
as a parental species and suggest that both cannot be determined under field condi-
hybrids are the result of matings between
tions.
Stellula calliope and the larger C. anna. Lamb, an experienced field collector,
The hybrids are similar in size and shape identified the Baja hybrid as "Costa Hum-
(Table 2, Fig. 4). Wing, bill, and rectrix mingbird" {Calypte costae) in his field cat-
length measurements of the hybrids differ alog. We concur that the hybrid bears more
from the biparental character means by 0.1 than a superficial resemblance to C. costae,
to 6.8%, whereas rectrix width measure- particularly in the color and shape of the
ments differ by 2.9 to 19.6% from the av- gorget.
erages of the character means ofthe paren- The Louisiana hybrid was studied at
tal species. close range by experienced observers for
760 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
the crown or sides of face [which]
. . .
should be conspicuous for adult S Anna's
cannot see any rufous along the edges
. . .
of the tail while the bird is perched . . .
which would be easily visible for an adult
S Broad-tailed the color of the gorget
. . .
appears more along the shade for Broad-
tailed rather than Anna's the shape of
. . .
the gorget is odd . . . there appears to be a
few incomplete feathers on the chin and
feathers protrude out on the edges of the
gorget almost Costa's like."
. . .
McKenzie noted that a second observer
16 17 saw rufous in the tail, whereas a third be-
lieved "the bird to be a typical Anna's."
Bill Length
Finally, McKenzie (24 November)reported,
"some birders have apparently seen rose-
red on the crown and face but I can't see it
although (again) the sun is not out." He
speculated that the hummingbird might be
a hybrid between C. anna and S. platycer-
cus.
Understandably, none ofthe fieldobserv-
ers suggested the possibility that the hybrid
was C. anna X S. calliope. Subtle shape
and colorcharacters thatpermittedtheiden-
tification of parental species from speci-
mens would not have been visible on free-
living birds, nor could the hybrids have
been conclusively diagnosed solely from
plucked rectrices or photographs.
20 25 30
Both C. anna and S. calliope are occa-
Length Rectrix 1 sional winter vagrants to the Gulf coast
Fig. 4. Bivariate plots ofmale Calypte anna (cir- from Texas to Florida (Newfield 1984, un-
c(ltersi)a,nglSetse,lluMlaVZcal4l7io9p8e3(adinadmoLnSdsU),MZand15t4h1e8i9r).hyLbreiadsst publ.); perhaps it is not surprising that a
hybrid ofthe two species might occur there
squares regression lines are illustratedforcomparison.
as well. However, at least three additional
presumed hybrids {S. rufus X S. sasin) have
several weeks in the vicinity of a nectar been collected in this general region in re-
feeder before it was collected. The hybrid cent years (see Newfield 1983). This seems
emitted a high-pitched song similar to that unusual and suggests an alternative hypoth-
of C. anna and loud call notes ("tsick, esis that the migratory orientation and be-
tsick, tsick .") (Paul McKenzie, field havior oftrochiline hybrids is faulty. In oth-
. .
notes). McKenzie (19 November 1993, field er words, the proportion of hybrids may be
notes) wrote, "looks more like a Broad- higher outside the "normal" geographic
tailed [Selasphorusplatycercus] in somere- range of the parental species. Another pos-
spects but suggests Anna's [C anna] inoth- sibility is that the prevalence of hybrids is
ers .. no sign of any reflective feathers on geographically invariant, but that hum-
.
VOLUME 109, NUMBER4 761
mingbirds are scrutinized more closely in Acknowledgments
easAtreernthNeorrethlimAimtesrtioc—sai.ze differencesamong BatWoen tRhoaungkeOf.orJ.pearnmdittHionpgethWeilhlyibarmisd otof
hybridizing species? The body mass ratio
be collected, Miriam Davey for providing
(larger divided by smaller) of Calypte anna
information, and Paul McKenzie for shar-
and Stellula calliope is approximately 1.6, ing his field notes. We are grateful to Van
regardless ofwhich species is female (mass Remsen and Steve Cardiff (LSUMZ) and
data from Stiles 1971). Although this size Ned Johnson (MVZ) for loaning the hybrid
bdieflfoewrentcheeimsastxriikmiungm, tohbesmeravsesdraatmioonisgweilnl- specimens, Carla Cicero (MVZ) forprovid-
ing copies of Chester Lamb's field notes,
terspecific hybrids of birds (Graves, un-
and Carl Hansen (USNM) for photograph-
publ.). Mayr and Short (1970) reported a
ing specimens. Richard Banks, Kenneth
possible hybrid between Lampornis cle- Parkes, Van Remsen, and Tom Schulenberg
menciae and Calypte costae or possibly C.
made helpful comments on the manuscript.
anna. If this combination is correct, the
minimum body mass ratio (i.e., S Calypte Collecting permits were issued by the Lou-
costae X 9 Lampornis clemenciae) would isiana Department ofWildlife and Fisheries
and the United States Fish andWildlife Ser-
be approximately 2.3 (mass datafrom Stiles vice. Museum research was supported by
1971, R. L. Zusi, unpubl.).
the Research Opportunities Fund and the
This raises the question of paternal ef- Alexander Wetmore Fund (Division of
fects on avian hybrid viability. Heritability
Birds) of the Smithsonian Institution.
(h^) of egg size is moderately high in wild
birds (Buckley 1982), and the volume of
Literature Cited
nutritive components of the egg are natu-
rally controlled by the female of a hybrid- American Ornithologists' Union. 1983. Check-list of
izing pair. In cases in which the smaller of North American birds, 6th edition. A.O.U.,
mtwaoyhnyobtridbiezilnagrgsepeecineosugishfteomalseu,pptohret etghge Banks,WNRao.srhtCihn,gAtm&oenr,Ni.cDa.KCn..,hJyo8bh7rn7isdopnph..um1m9i6n1g.biArdsr.ev—ieCwono-f
metabolic and volumetric needs of the de- dor 63:3-28.
veloping embryo after factoring in additive Bent, A. C. 1940. Life histories of North American
genetic effects of the male. cuckoos, goatsuckers, hummingbirds and their
The ratio of average egg volume of C. allies; ordersPsittaciformes,Cuculiformes,Tro-
goniformes, Coraciiformes, Caprimulgiformes
anna and S. calliope is approximately 1.2, andMicropodiiformes.—UnitedStatesNational
calculated from the data in Bent (1940). Museum Bulletin 176:1-506.
Curiously, however, the range of egg vol- Berlioz,J. 1930. Anewhummin—gbirdhybrid, Calypte
ume for S. calliope (ca. 299-611 mm^) anna X Stellula calliope. Condor 32:215.
completely overlaps that of the larger C. Buckley, R A. 1982. Avian genetics. Pp. 21-110 in
M. Petrak, ed.. Diseases of cage and aviary
anna (342-591 mm^) (calculated from the birds. 2nd ed. Lea and Febiger, Philadelphia,
dimensions of size extremes reported in 680 pp.
Bent 1940). Thus, despite the specific dif- Fisher, A. K. 1893. Report on the ornithology ofthe
ference in body mass, egg volume per se Death Valley expedition of 1891, comprising
notes on the birds observed in southern Cali-
appears not to inhibithybridizationbetween
the species. On the otherhand, egg volumes afonrdniUat,ahs.ou—thNeorrnthNeAvmaedrai,caanndFapuarntas7o:f7-A1r5i8z.ona
of C. costae (ca. 276-572 mm^) and L. cle- Graves, G. R. 1990. Systematicsofthe "green-throat-
menciae (ca. 662-857 mm^) are non-over- edsunan—gels" (Aves:Trochilidae): validtaxaor
lapping, suggesting that viable hybrids of hybrids? Proceedings of the Biological Soci-
those species may only be fathered by C ety ofWashington 103:6-25.
costae. Egg volumes ofthe pairs ofhybrid- s.tri1at9a96.X DHeynbdrriodicawocoadstawnaerabl(eArsv,es:DeFnridnrgoililcia-
izing species listed in Table 1 overlap. dae) and the diagnostic predictability of avian
— —
762 PROCEEDINGS OFTHE BIOLOGICAL SOCIETY OF WASfflNGTON
—
hybrid phenotypes. Proceedings of the Bio- chilochus alexandri, Calypte anna, Calypte costae,
logical Society ofWashington 109:371-388. Stellula calliope, Selasphorus platycercus, Selaspho-
-, & R. L. Zusi. 1990. An intergeneric hybrid rus rufus, Selasphorus sasin.
hummingbird{Heliodoxaleadbeateri X Helian-
gelus amethysticollis) from northern Colom-
bia.—Condor 92:754-760. Appendix 2
Grinnell, J. 1928. A distributional summa—tion of the
ornithology of Lower California. University Comparativedescriptionofmale Calypteanna, Stel-
ofCaliforniaPublicationsinZoology32:1-300. lula calliope, and their hybrids collected in Baja Cal-
Griscom, L—. 1934. TheornithologyofGuerrero,Mex- ifornia (MVZ 47983) and Louisiana (LSUMZ
ico. Bulletin of the Museum of Comparative 154189). Descriptions of structural colors are unusu-
Zoology 75:368-422. ally subjective, as color seen by the observer varies
Hartert, E. J.—1900. [Exhibition of hybrid humming- according to the angle of inspection and direction of
birds.] Bulletin of the British Ornithological light.Forthisreasonweusegeneralcolordescriptions.
Club 10:39-40. The forecrown, superciliary, crown, hindneck, back
Huey, L. M. 1944. —A hybrid Costa's X Broad-tailed andrumpofcalliopearegreenwithbronzytoning;the
hummingbird. Auk 61:636-637. loral streak is pale grayish-white. In anna, the fore-
Jeffriesn,eJw. As.pec1i8e8s8.ofATdreoscchriilputsiofnroofmaCnalaipfopranriean.tly cdrroawwnn,alcorroaslsrtehgeiocn,roawnnd3c-r5owmnm(abnetheirinodrtfhreoemyea)lairnee
Auk 5:168-169. feathered with brilliant, iridescent rose-red discs;
Lynch, J. E, & P. L. Ames. 1970. A newhybridhum- plumage from the hindneck to the rump is green,
mingbird,Archilochusalexandri X Selasphorus slightly bronzier on the hindneck and scapulars than
—
sasin. Condor 72:209-212. in calliope.
Mayr, E., & L. L. Short, Jr. 1970. Species taxa of In the Baja hybrid, feathers above the nostrils are
North America bir—ds, acontribution to compar- brownish-grayanddimlyreflective(rose-purple)under
ative systematics. Publications of the Nuttall lOX magnification; iridescentreddish-purple discs ex-
Ornithological Club no. 9. tendfromthe forecrownlaterally alongthemarginsof
Newfield, N. L. 1983. Records ofAllen's Humming- the crown to the rear of the orbits; a few feathers on
birdinLouisianaandpo—ssibleRufous X Allen's the crown (between the eyes) are tippedwithdullpur-
Hummingbird hybrids. Condor 85:253-254. plish spots. The loral area is buffy-white with dark
. 1984. Three recor—ds of Calliope Humming- terminal spots on some feathers. The frontal reflective
bird from Louisiana. Condor 86:346-348. display in the Baja hybrid is more subdued than in
Ortiz-Crespo, F. I. 1972. A new method —to separate anna; the "plate-like" arrangement ofbarbules ofiri-
immature and adult hummingbirds. Auk 89: descent discs is less well-developed, and several red-
851-857. dish-purple discs exhibit greenish iridescence nearthe
Short, L. L., Jr., & A. R. Phillips. 1966. More—hybrid distal margins. The remainderofthe crown, hindneck,
hummingbirds from the United States. Auk back, and rump are indistinguishable from calliope.
mm
83:253-265. Feathers ofthe forecrown and crown (to 3 be-
Stiles, E G. 1971. On the fi—eld identification ofCali- hind the eye) of the Louisiana hybrid have terminal
fornia hunmiingbirds. California Birds 2:41- discs that emit a dull coppery-rose iridescence when
54. viewed head-on in direct light. The frontal reflective
Suchetet, A. 1896. Des hybrides a I'etat Sauvage. display is less brilliant than in the Baja hybrid (much
TomeI, classedesoiseaux. Paris,J. B. Bailliere less so than in anna). Undermagnification, disc feath-
et Fils. 1001 pp. ers are banded: gray basally, bordered distally in suc-
Thayer,J.E., &O. Bangs. 1907. Anotherhybridhum- cession by narrow iridescent bands of shining green
mingbird Selasphorus rufus + Atthis callio- andreddish-purplemergingintoabroadterminalband
pe-irom California.—Auk 24:312-313. ofbronzy- or coppery-rose, with faint greenishreflec-
Wells, S., R. A. Bradley, & L. E Baptista. —1978. Hy- tions. Feathers of the loral area are buffy-white, oc-
bridizationin Calyptehummingbirds. Auk95: casionally tipped with small and indistinct dark spots.
537-549. Feathers ofthe hindcrown, back, and rump are green,
nearly identical in appearance to calliope and most
specimens ofanna, butfinelymarginedwithbuff,per-
Appendix 1 haps reflecting the freshness ofplumage.
The gorget in calliope covers the chin and throat
Species that regularly breed in Baja Californiaand/ andextendslaterallyalongthesidesofthelowerthroat
or in the United States and Canada: Cynanthus lati- toformafringedbuttaperedpoint. Gorgetfeathersare
rostris, Hylocharis xantusii, Amazilia yucatanensis, tricolored;proximallywhite,borderedwithaverynar-
Amazilia violiceps, Lampomis clemenciae, Eugenes row transitional band of bronzy-green, and broadly
fulgens, Calothorax lucifer, Archilochus colubris, Ar- tipped with brilliantly iridescent discs (purplish-red).
VOLUME 109, NUMBER4 763
The purplish-red portions offeathers are greatly elon- minaldisc. Onmostdiscs,thedominantreflectedcolor
gated in the lateral tails of the gorget. White feather varies proximally from coppery purplish-red to cop-
basesresultinconspicuousstreaking,especiallyonthe pery rose-red distally. The reddish portions of lateral
centerofthe throat. A subocularstripeofgrayish-buff gorgetfeathersarenotaselongateasthoseofcalliope,
feathers extends from the loral area to the auriculars. anna, or the Baja hybrid. White featherbases are vis-
The gorget is bordered posteriorly by a band ofwhite ible at the sides of the throat, and especially on the
plumage across the lowerthroat andupperbreast. The chin andupperthroat. Thepalegrayish-buffsubocular
sides, flanks, andbelly arebuffy-gray, palestalongthe stripe is sprinkled with tinyreddishdiscs; gorgetdiscs
midline;feathersonthesidestippedwithbronzy-green extend dorsally to the eyering and auriculars as in
spots. The undertail coverts are very pale buffy-white anna. The gorget is bordered posteriorly by a white
or white, some with a few indistinct grayish spots. bandthatdarkenstolightgrayontheupperbreastand
Therose-redgorgetinanna has asimilarshape, but alongthemidline.Feathersofthesidesandflankshave
the iridescent discs are more imbricated than in calli- large green subterminal spots and pale buffy margins
ope and extend to the subocular region. Lateral discs (especially prevalent on the flanks). The undertail co-
are less elongate than in calliope and all gorgetfeath- verts are very pale grayish-white with pale greenish-
ers are dark gray to bronzy-gray basally. Feathersjust gray subterminal spots (a few with buffy-white mar-
posteriortothegorgetaredullbrownishgraywithpale gins), more pronounced than those of calliope or the
gray tips. The remainder of the underparts are dark Baja hybrid.
gray; feathers ofthe sides, flanks, belly, and undertail Wingcolorofcalliope, anna, andthehybridsissim-
coverts have dull bronzy-green subterminal spots. ilar. Primary shape in the hybrids is intermediate be-
Some males exhibit traces ofrosey iridescence on the tween that of calliope ("squared" primaries 5, 6, 7,
sides and flanks. and 8) and anna (tapered) (see Banks and Johnson
The distribution, shape, and disc color of gorget 1961).
Rectrices in calliope are dull brownish-blackwitha
feathers in the Baja hybrid are intermediate between
thoseofcalliopeandanna. Basally,gorgetfeathersare bronzysheen, slightlygreeneronthedistalVzofrectrix
white orverypalegrayish-white, andhence, morelike 1 and 2; the proximal half of the medial and lateral
calliopethananna. Avery narrow transitionalbandof webs ofrectrix 1, 2, 3, and 4 (medial web only) are
green separates the white base from the terminal pur- margined with rufous. The central pairofrectrices (1)
A are semispatulate (web margins proximalto thetipare
plish-red disc. buffy-gray subocularstripe separates
concave);themarginsofrectrix2areslightlyconcave.
the eyering from the gorget as in calliope. The re- Rectrix 1 of anna is bright bronzy-green, rectrix 2
mainder of the underparts are nearly intermediate to is slightly darker. The outer rectrices (3, 4, and 5) are
thatofcalliope andanna. The throat, immediatelyad- gray along the margins (especially medially), grading
jacent to the gorget, is white, darkening to medium to grayishblack along therachis and towardthedistal
grayonthelowerbreast, sides,flanks,andbelly;feath- tip. Rectrices lack rufous pigmentation or concave
ers on the sides and flanks have green subterminal margins.
spots. The undertail coverts (white with a large but Shape and pigmentation ofrectrices in the hybrids
nearly imperceptible grayish subterminal spot) are are intermediate between those of calliope and anna.
most similarto those ofcalliope. Overall, thepatternofpigmentationontherectricesof
The gorget of the Louisiana hybrid lacks well-de- the Baja hybrid more closely resembles that of calli-
veloped lateral extensions observed in calliope, anna, ope; thecentral rectrices are only slightlygreenerthan
and the Baja hybrid, and superficially resembles that the outer rectrices, and rufous occurs on the medial
ofSelasphorusplatycercus in colorand shape. Gorget (rectrix 1, 2, 3, and 4) and lateral (rectrix 1, 2, and 3)
feathers arepalegrayish-whitebasally(darkernearthe margins. Rectrices of the Louisiana and Baja hybrid
rachis). A narrow bronzy-green band separates the are similar, but rectrix 1 and 2 ofthe Louisiana spec-
white feather base from the brilliantly iridescent ter- imen are greener (approaching the color ofanna).
