A Unique Ornament Display in Female Northern Cardinals

4 Pages·2003·2.9 MB·English

by  Jodie M Jawor

Short Communications
Wilson Bull., 115(4), 2003, pp. 464-^67
A
Unique Ornament Display in Female Northern Cardinals
Jodie M. Jawor^’^ and Randall Breitwisch^
—
ABSTRACT. Females of many species of birds (e.g., to reduce nest predation; Martin and
possess either a reduced version ofmale ornaments or Badyaev 1996). There has been little empiri-
ocornnsapmiecnutoudsisbpultayhihdadsenbeoernnamdeesnctrsi.beNdopfreemvailoeusslpyeciinfiac cal support for Lande’s correlated response
species with reduced or hidden female ornaments. We hypothesis. However, there is growing support
describe such a display in Northern Cardinals (Cardi- for the alternative hypothesis of sexual selec-
nalis cardinalis). The display consists ofaperched fe- tion maintaining female ornamentation, even
male rotating her wings open to expose the red, carot- when ornamentation is reduced in expression
enoid-pigmented underwing coverts, which are indic- (Amundsen 2000).
ative ofindividual quality in this species. Received 19 Studies on sexual selection and ornamen-
March 2003, accepted 21 September2003.
tation focus on the signal value of ornaments
within the context of mate choice. In species
with subdued ornament expression in females,
Birds are some of the most elaborately or-
namented vertebrates. Many studies have ad- ornaments have been linked to aspects of
quality such as body size, the ability to pro-
dressed ornaments in males and their use in
duce nests early in the breeding season, the
mate choice and intrasexual competition as in- ability to produce many eggs, or the ability to
dicators ofcondition or behavior (reviewed in
Andersson 1994). The relatively few studies resist disease (Burley et al. 1992, Mpller
1993, Owens et al. 1994, Amundsen et al.
on female ornamentation present evidence that
1997, Roulin et al. 2000, Romero-Pujante et
female ornaments can be used similarly in
al. 2002). In some species with subdued fe-
mate choice and intrasexual competition (re-
male ornamentation, the ornaments are visu-
viewed in Amundsen 2000), yet no previous
ally hidden on females, presumably as a result
studies have described such a female specific
of natural selection. For instance, the female
display. Here we describe such a display in ornament may be relatively brightly colored
Northern Cardinals {Cardinalis cardinalis).
feathers on the ventral surface ofthe wing, not
There are three gender patterns of orna-
visible when the bird is perched, but visible
mentation in birds. In the first, the sexes are in flight. We have found no previous reports
monomorphic in ornamentation. In the sec-
ond, less common pattern, females possess ohfiddspeencioersnaimnenwthsictho fmeamlaelse,saosvewretlyhadviespolba-y
more elaborate ornamentation than males. In
the third, the most common pattern, females served in female Northern Cardinals.
Male cardinals possess red plumage over
possess a reduced version of the more elabo-
the whole body, a tall head crest, a red-orange
rate male ornament. Lande (1980) developed
bill, and a large black face mask. Female car-
the correlated response hypothesis to describe
dinals are tan in overall plumage color, pos-
this last pattern. Under this hypothesis, female
sess a similarly tall head crest and red-orange
ornaments are not sexually selected but rather
are the result of genome sharing between the bill, but have a smaller, less distinct face mask
and have red underwing coverts. Female face
sexes and strong selection for elaborate male
mask expression, bill color, and underwing
ornamentation. Female ornaments are reduced
covert color all indicate aspects of individual
in expression in response to natural selection
quality (Jawor et al. in press). Male cardinals
perform a variety of physical displays during
' Dept, of Biology, Indiana Univ., Bloomington, IN courtship that draw attention to ornaments,
47405, USA.
^Dept, of Biology, Univ. of Dayton, Dayton, OH particularly the bright red plumage of the up-
45469-2320, USA. per breast (e.g., song-dance display, song-
'Corresponding author; e-mail:[email protected] flight, alert display, and territorial singing dis-
464
SHORT COMMUNICATIONS 465
play; Lemon 1968). No female displays ofor- the breeding season and during mid- to late
namentation have been described previously morning. We did not observe copulations or
in cardinals (see Halkin and Linville 1999). copulation attempts following the female dis-
We observed on seven occasions female play, although in each instance the male ap-
cardinals displaying their underwing plumage proached within 1 m ofthe displaying female.
to males during breeding seasons between Each male was positioned for good visibility
1991 and 2002. Other researchers also have 2-7 m away from the female when the display
observed this display in female cardinals (N. was performed, and each male approached the
Gray, S. U. Linville, P. M. Nealen, and L. L. displaying female either during or within 5 s
Wolfenbarger pers. comm.). In this display, a ofher display. Following the male’s approach,
female perches in an accentuated upright pos- the pair left the area or moved into dense veg-
ture facing a male, with crest erect, while etation. We did not observe the male giving
holding her wings out from her body. The displays of his own during the time when a
wings are not fully extended but rather bent female displayed, nor was any male heard to
at the wrist, with primaries pointed down- sing. The male did not appear to investigate
ward. The posture is reminiscent of a person the displaying female’s plumage upon landing
holding open a jacket. The red, carotenoid- near her, but it is probable that the male car-
pigmented underwing coverts are presented to dinal could see the underwing plumage from
the male. This posture is held for <5 s. There several meters away. Although during our ob-
is no female vocalization accompanying the servations of this display the male did not
visual display. The lack of vocal announce- then feed the female, one researcher (P. M.
ment and short duration of the display likely Nealen pers. comm.) has observed this se-
are the reasons that we have observed this dis- quence ofevents. All displays were performed
play so infrequently, despite hundreds of 5-8 m above ground in crowns of trees with
hours of focal observations of pairs of cardi- sparse leaf cover. Displays do not appear to
nals. The stance of the female is unlike that take place near the nest, as all observed dis-
in a copulation solicitation display or a court- plays were well above the mean nest height
ship feeding solicitation display (both given in this species. We do not know the displaying
by female cardinals), as the female remains females’ stage of reproduction. The observed
upright with her tail held straight down. Dur- displays occurred either early in the breeding
ing the lopsided display (Lemon 1968) a male season before we had found an active nest (al-
cardinal may lift one wing while displaying though one may have been present) or later in
the underside of the body. This display is the season in cases where we had not yet
quite different from the female display de- found a new nest for this repeatedly nesting
scribed here in that only one wing is lifted and species.
partially extended away from the body, while Additional findings with cardinals suggest
the body is lowered and rotated about its axis that the described display may communicate
(see Lemon 1968 for illustration). information on individual quality. In females,
All of the female displays we observed the underwing plumage is indicative of mul-
were given toward males. The members of tiple aspects of quality (body size, body con-
one pair were both identified by band com- dition, date of first nest produced, and repro-
binations during the display. For five of the ductive success; Jawor et al. in press). Also,
remaining six displays observed, only one cardinal pairs mate assortatively by ornamen-
member of the pair was identified. Either the tation (Jawor et al. 2003); cardinal pairs pos-
male or the female was identified by color sess similar bill colors, and the redness of
bands during the display, and all five occurred male upper breast plumage color is positively
within the boundaries ofknown territories. We correlated with the redness of his mate’s un-
observed the seventh display in a nearby un- derwing plumage color. Assortative mating is
banded population. We assume that the recip- suggestive of bidirectional mate choice, and
ient of the display was the female’s mate, but the described female display may facilitate
it is possible that this display was given to a male assessment of this condition-dependent
male other than the mate. ornament in female cardinals. This display
We observed displays both early and late in may be integral to the formation ofnew pairs.
466 THE WILSON BULLETIN • Vol. 115, No. 4, December2003
Males display their quality to females via or- ACKNOWLEDGMENTS
namentation, and our observations suggest a We thankN. Gray, S. U. Linville, P. M. Nealen, and
reciprocal display of female quality. For es- L. L. Wolfenbarger for communicating their observa-
tablished pairs, this display also may maintain tions ofthis display. We thank C. Krueger and J. Wil-
pair bonds, or provide information to males son of Aullwood Audubon Center and Farm for per-
on female receptivity to copulations. Cardi- mission to use the Aullwood facilities. We also thank
J. A. Smallwood and three anonymous reviewers for
nals nest repeatedly during the breeding sea- comments on a previous version ofthis manuscript.
son (Filliater et al. 1994) and divorces occur
both within season and during winter (JMJ LITERATURE CITED
and RB unpubl. data). This situation would Amundsen, T. 2000. Why are female birds ornament-
favor the display of individual quality at mul- ed? Trends Ecol. Evol. 15:149-155.
tiple times during the year, even in established Amundsen, T, E. Gorsgren, and L. T. T. Hansen.
pairs. Some of these suggested functions 1997. On the function offemale ornaments: male
could be tested with captive cardinals in avi- Bluethroatsprefercolourfulfemales.Proc.R. Soc.
Lond. B 264:1579-1586.
ary experiments, although this species does Andersson, M. 1994. Sexual selection. Princeton
not thrive in captivity (L. L. Wolfenbargerand Univ. Press, Princeton, New Jersey.
G. E. Hill pers. comm.). Burley, N. T, D. K. Price, and R. A. Zann. 1992.
It is clear that natural selection has acted in Bill color, reproduction and condition effects in
some bird species to reduce female ornamen- wild and domesticated Zebra Finches. Auk 109:
13-23.
tation from the more conspicuous male ex- Burns, K. J. 1998. A phylogenetic perspective on the
pression (Burns 1998). Less appreciated is the evolution of sexual dichromatism in Tanagers
fact that this process has yielded hidden or- (Thraupidae): the role of female versus male
naments that are not easily assessed when a plumage. Evolution 52:1219-1224.
female is perching, incubating eggs, or brood- Filliater, T. S., R. Breitwisch, and P. M. Nealen.
1994. Predation on Northern Cardinal nests: does
ing nestlings. Hidden ornaments consist of
choice ofnest site matter? Condor 96:761-768.
brightly colored underwing coverts, primaries, Halkin, S. L. and S. U. Linville. 1999. NorthernCar-
secondaries, undertail body coverts, or tail dinal (Cardinaliscardinalis). No.440inThebirds
feathers that are not easily observed unless the ofNorth America(A. PooleandE Gill,Eds.).The
tail or wings are spread. There are many North Birds ofNorth America, Inc., Philadelphia, Penn-
sylvania.
American species of birds in which females Jawor, j. M., N. Gray, S. M. Beall, and R. Breit-
possess ornamental coloration that is so hid- wisch. In press. Multiple ornamentscorrelatewith
den, e.g., many warblers, PyiThuloxia {Car- aspects of condition and behaviour in female
dinalis sinuatus). Crimson-collared Grosbeak NorthernCardinals {Cardinaliscardinalis).Anim.
Behav.
{Rhodothraupis celaeno). Black-headed Gros-
beak {P/ieucticus melanocephalus), and Rose- Jawor, J. M., S. U. Linville, S. M. Beall, and R.
Breitwisch. 2003. Assortative matingby multiple
breasted Grosbeak (Pheucticus ludovicianus). ornaments in Northern Cardinals, Cardinalis car-
We predict that at least some species with hid- dinalis. Behav. Ecol. 14:515—520.
den female ornaments also possess female Lande, R. 1980. Sexual dimorphism, sexual selection
limited ornament displays. and adaptation in polygenic characters. Evolution
34:292-305.
Lande’s (1980) coiTelated response hypoth- Lemon, R. E. 1968. The displays and call notes of
esis assumed that female ornaments are sub- cardinals. Can. J. Zool. 46:141-151.
dued in expression due to the influence ofnat- Martin, T. E. and A. V. Badyaev. 1996. Sexual di-
ural selection. We believe this assumption is chromatism in birds: importance ofnestpredation
warranted. However, this does not mean that and nest location for females versus males. Evo-
lution 50:2454-2460.
subdued or hidden ornaments cannot serve as M0LLER, A. P. 1993. Sexual selectionintheBarnSwal-
indicators of female quality under sexual se- low Hirundo rustica. III: female tail ornaments.
lection. Hidden ornaments in female birds Evolution 47:417-431.
and, perhaps, female limited displays of these Owens, I. P. E, T. Burke, and D. B. A. Thompson.
1994. Extraordinary sexrolesintheEurasianDot-
indicators of quality likely are a compromise terel: female mating arenas, female-female com-
between natural and sexual selection both act- petition, and female mate choice. Am. Nat. 144:
ing directly on females. 76-100.
SHORT COMMUNICATIONS 467
Romero-Pujante, M., H. Hoi, D. Blomqvist, and F. Roulin, a., T. W. Jungi, H. Pfister, and C. Dijk-
Valera. 2002. Tail lengthandmutual matechoice STRA. 2000. Female Barn Owls {Tyto alha) ad-
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Wilson Bull., 115(4), 2003, pp. 467^70
Group Copulation Solicitation Display among Female Greater Rheas
Gustavo J. Fernandez’’^ and Myriam E. Mermoz^
—
ABSTRACT. In this paper we report the copula- from 2 to >10 females (usually 4-6). The
tion behavior of the Greater Rhea (Rhea americana), male copulates with each female in his harem
aWespedceisecsriibnewthheicfhemmaalleess’ dbeefheanvdioar hduarrienmgo1f4fceompaulleas.- at least once every 2-3 days, and the females
tion events observed from 1995-1997 at Buenos Aires lay their eggs in a single communal nest built
province, Argentina. During copulations, females per- by the male. The male performs all incubation
formed a more active role than previously suggested. and chick-rearing behaviors. Once the egg
Moreover, on three occasions we observed that harem laying at a particular nest is completed, the
females performed a complex copulation solicitation females sometimes mate with other males
display, forming aclosed circle to attract the male. We (Astley 1907, Bruning 1974). Thus, this mat-
hypothesize that this display could be a reliable signal ing system combines harem (female defence
to the male of the tendency of females to be insemi-
nated and lay eggs communally. Received 10 June polygyny) with sequential polyandry (Oring
2003, accepted 15August 2003. 1982, Jenni 1974).
We observed Greater Rheas at General Lav-
alle (36° 25' S, 56° 56' W), Buenos Aires
The Greater Rhea {Rhea americana) is a province, Argentina, during the breeding sea-
precocial flightless bird that inhabits grass- sons of 1995-1997. The study area is a tem-
lands and other open habitats in the southern perate grassland of the flooding Pampa (So-
Nteiontarmoopuisc,s.arReheausn,usluiakle oatmheorngratibtiersdsandinsothmaet rmiaarnsohy,19w9i1t)h. mTohset ltaenrdra<in10ismfalabto,veloswe,a laenvd-
they combine a complex mating system with el (see description in Fernandez and Reboreda
uniparental care by males. Previous studies 1998). We made observations from 7:00-19:
describing the mating behavior of Greater 00 EST from a vehicle located 100-200 m
Rheas emphasized that males perform con- from rhea groups.
spicuous reproductive behavior (Raikow We observed a total of 14 copulations in-
1969, Bruning 1974). Female behavior, how- volving seven males. All copulations occurred
ever, has been poorly described, focusing during morning (7:00-11:30, n = 6) or even-
mainly on egg laying. Here we describe the ing (16:00-19:00, n = 8), and copulations
mating behavior of wild Greater Rheas, in- lasted 1-2 min. The minimum observed time
cluding a previously unrecorded copulation between successive copulations by the same
solicitation display performed by the females. male was 20 min. For nine copulations we
Early in the breeding season (August to monitored the group before copulation solic-
September) male rheas compete for and de- itation took place. In six instances the male
fend a group of females. Harem sizes vary approached an isolated female of the group
while she fed and he started to perform court-
ship displays. These involved mostly head-
' Dep. de Ecologia Genetica y Evolucion, Facultad bobbing, in which the male moves his head
drees.CiInetn.cGiiaisirEaxladcetsass/ny. NPaatbuerlalloens,2,UnCiivu.daddeUBnuievenrossitAair-- vigorously up and down (Raikow 1969). The
ia. C1428EHA Ciudad de Buenos Aires, Argentina. female responded to the displaying male by
2Corre.sponding author; e-mail: [email protected] lowered her head and then remaining motion-