Table Of ContentWilson Bulletin, 116(2), 2004, pp. 167—171
PREDATION RISK ASSOCIATED WITH GROUP SINGING IN A
NEOTROPICAL WOOD-QUAIL
AMANDA M. HALE'
—
ABSTRACT. Decades of fruitful research on the study of vocal communication in birds have provided
surprisingly little evidence ofa predation cost associated with singing. In this paper, I report the first observa-
tional evidence of a risk of predation associated with chorusing in a Neotropical wood-quail. Black-breasted
Wood-Quail iOdontophorus leucolaemus) live in groups year-round and produce coordinated group choruses or
duets. Three mammalian and two avian species ofpredators were attracted to playbacks ofrecorded wood-quail
choruses that I used during population surveys and capture attempts from March to August, 2000-2002. The
trade-offbetween signaling and predation risk may be an important force in the evolution ofchorusing in New
World quails. Received 12 February 2004, accepted 19 July 2004.
Long distance vocalizations are used for (Yasukawa 1989). Two recent studies provide
territory defense, mate attraction, and other additional experimental support: Brown Skuas
functions in a variety of animals (Bradbury (Stercororius antarcticci) use the mate attrac-
and Vehrencamp 1998, Todt and Naguib tion calls of colonially nesting seabirds as a
2000). Whenever such signals are sent, how- cue for prey location and selection (Mougeot
ever, there is a danger that they will be heard and Bretagnolle 2000), and long-distance call-
and taken advantage ofby illegitimate receiv- ing in Crested Tits {Pants cristatiis) increases
ers, such as competitors, parasites, or preda- the risk of predation by Eurasian Sparrow-
tors (McGregor 1993, Bradbury and Vehren- hawks (Accipiter nisiis; Krams 2001).
camp 1998, Haynes and Yeargan 1999). For In this study, I report observational evi-
example, the parasitoid tachinid fly, Onnia dence that predators are attracted to group
ochracea, is attracted to tape recordings of a singing in Black-breasted Wood-Quail {Oclon-
host cricket, GryUiis integer (Cade 1975); the tophorus leucolaemus), a social species re-
fringe-lipped bat (Trachops cirrhosiis) uses stricted to the remaining highland forest of
acoustic cues to capture calling frogs (Tuttle Costa Rica. Black-breasted Wood-Quail live
and Ryan 1981); and several species of fo- in coveys year-round (2 to 15 individuals) in
liage-gleaning bats in Panama use the mate- the dense understory of cool, wet forest be-
attracting songs of male katydids to locate tween 900 and 1,600 m elevation. Nesting
these prey (Belwood and Morris 1987). In usually occurs around the onset of the rainy
birds, however, evaluation of predation costs season in May and June (McDonald and Win-
AMH
associated with signaling has primarily been nett-Murray 1989; pers. obs.). Coveys
restricted to studies of plumage conspicuous- defend group territories and produce coordi-
ness (Gotmark 1992, Promislow et al. 1992, nated group choruses or duels. Neighboring
Andersson 1994). Although most studies of coveys are most often heard calling back and
costs associated with vocal communication in forth just after dawn. All members ofthe cov-
birds have focused on energetics (Eberhardt ey participate in the chorus, and individuals
1994, Oberweger and Gollcr 2001, Thomas often hop up on perches (dead fallen trees)
2002), eavesdropping by predators has been approximately I m off the ground while sing-
demonstrated experimentally in three species. ing. Depending on the weather and terrain, the
TsthuedyfirsotfexRpeedr-iwmeinntgaeldevBildaecnkcbeircdosme{sAgeflraoimitas cofhor2u()s()-i5s()a(u)dimble(AtoMhHumpaenrss. forbosm.).a dBiesctaaunscee
choruses and duets by a single mated pair
phoenicens), in which nests accompanied by
have the same basie strueture in Blaek-breasi-
playback of female ‘chit' calls were depredat-
ed Wood-Quail, hereafter will refer to both
ed at higher rates than nests without playback I
as choruses.
Mi:rn()i)s
' Dept, of Biology, Univ. ot Miami. I’.O. Box
2491 IX. Coral Cables. I'l. 3.M24, U.SA: e-mail: The study area is loeated in Montevertle
ahale^^bio.miami.edu (10° 15' N, 84° 46' W ). a 1,500-ha dairy farm-
167
168 THE WILSON BULLETIN • Vol. 116, No. 2, June 2004
ing community at an elevation of 1,350-1,500 determine whether wood-quail coveys adjust-
m on the Pacific slope of the Cordillera de ed their responses to playbacks based on the
Tilaran in Puntarenas Province, Costa Rica. number of individuals in the “intruding” cov-
This area is the site of long-term ecological ey. These 16 choruses were chosen based on
studies and has been well described (Nadkarni the clarity ofthe recording and the absence of
and Wheelwright 2000). Monteverde is a frag- other sounds, including singing by other spe-
mented landscape, composed of open pas- cies, wind, and rain. One of these tapes con-
tures, some cultivated bananas and coffee, and sisted of a 15-sec chorus that was looped to
considerable remnant pre-montane and lower make a 30-sec recording, while each of the
montane moist/wet forest (Holdridge 1967). other tapes consisted ofa single chorus lasting
The community lies on a narrow plateau 26-31.5 sec.
bounded on the north by human dwellings and To simulate territorial intrusions, I entered
agriculture, on the south and west by cliffs, a group’s territory and played a recording (30
and o—n the east by a large expanse of cloud sec from the cloud forest CD recording in
forest the 28,000-ha Monteverde Reserve 2000 and 2001, or one of the experimental
Complex, Costa Rica’s largest intact highland tapes in 2002) using a Sony Walkman, a 20-
forest. Black-breasted Wood-Quail inhabit the watt RMS power amplifier, and a 12.5-cm, 15-
large windbreaks and patches of remnant for- watt Speco loudspeaker (300-15,000 Hz)
est in the Monteverde community and the con- placed 0-2 m above the forest floor. If the
tinuous forest of the Monteverde Reserve group responded immediately, either by call-
Complex. Although locally common in the ing or approaching the loudspeaker, I did not
Monteverde area. Black-breasted Wood-Quail continue with playback. If the group did not
are generally rare throughout Costa Rica respond, I repeated the playback once every 3
(Stiles and Skutch 1989, Fogden 1993), and min for a maximum of 15 min. Amplitude lev-
are classified as a spec—ies ofconservation con- el ofthe playback was matched by ear to sing-
cern by the lUCN World Conservation ing wood-quail and was held constant
Union (Collar et al. 1994, Fuller et al. 2000). throughout the trials. In general, the playback
In Monteverde, average covey size is four was just loud enough so that the sound trav-
adults with approximately 11% of surveyed eled approximately 200 m and was not dis-
coveys containing three or more adults (/z = torted. Wood-quail coveys tended to respond
151 coveys). Average density is one covey per immediately when a recording was played
3.3 ha (AMH unpubl. data). within their territories; they would sing and
From March through August, 2000-2002, I approach within a few cm of the loudspeaker.
conducted wood-quail surveys in the Monte- Solitary individuals also responded to play-
verde area by using playbacks of choruses to backs by singing, but did not closely approach
simulate territorial intrusions. A single record- the sound source. I also used playbacks to lure
ing from the Indicator Birds ofthe Costa Ri- wood-quail into mist nets or large traps for
can Cloud Forest CD (Ross et al. 1997) was individual marking and genetic sampling. The
used in 2000 and 2001. This 58-sec recording number of times the recording was played
consisted of three choruses from a bout of during capture (from 1 to approximately 20
counter-singing between two coveys of un- times per hr) depended upon the response of
known size. The recordings used in 2002 were the focal group and the number of group
obtained from songs provoked by the use of members captured.
playback. Recordings were made from 64
RESULTS AND DISCUSSION
bouts of singing by 45 coveys; I used a Sony
Cassette Recorder TC-D5M and Audio- Wood-quail choruses are rushing gabbles of
Technica unidirectional microphone (70- notes patterned into two sets of paired sylla-
18,000 Hz). Digital sound files were created bles that are repeated over and over. Choruses
from the analogue recordings at 22.05 kHz last 10-60 sec and occur most oftenjust after
with 16-bit accuracy using Syrinx Version dawn (54% of spontaneous choruses occurred
2.2b (2001). Sixteen experimental tapes, con- between 05:30 and 06:30 GMT-6, n = 87 cho-
sisting of one chorus each from 16 coveys of ruses). The majority ofchoruses are answered
known size (range 2-7 adults), were made to by neighboring groups, and bouts of counter-
Hale • PREDATION AND GROUP SINGING IN WOOD-QUAIL 169
singing among neighbors last from about 1 approaching covey and pursued the quail on
min to over 1 hr (AMH unpubl. data). When foot as they ran for cover; two Collared For-
j two or more social groups come into contact est-Falcons and the Barred Forest-Falcon
I
near a territorial boundary, each group pro- perched on a branch located approximately 3
I duces a well-coordinated chorus and the m above the loudspeaker and visually
groups will either alternate or overlap their searched the immediate area; and the dogs ran
'
bouts of singing. Often, after a few bouts of directly at the loudspeaker before pausing and
i
counter-singing, one or more groups will re- searching the surrounding area. Two of these
treat from the area. In other instances, the ter- predators are forest specialists (Collared For-
ritorial encounters can last up to several hr. In est-Falcon, margay) and may be constrained
addition to continued singing during territorial to using vocal cues to locate prey. Unlike the
encounters, individuals produce several other other predators, the Barred Forest-Falcon is
vocalizations and participate in strutting dis- too small (165-200 g; Stiles and Skutch 1989)
plays, chases, and even physical fights with to capture adult wood-quail (mean = 295 g
I neighboring group members. Wood-quail cov- ±16 SD, n = 103 adults; AMH unpubl. data);
eys responded to simulated territorial intru- however, because these playback trials oc-
sions with either choruses or approaches dur- curred during the wood-quail breeding season,
ing 65% of surveys and 75% of capture at- it may have been looking for chicks.
tempts in 2000-2002 {n = 467 surveys and n Although energetic costs associated with
= 122 capture attempts). producing signals have received the most at-
During surveys and capture attempts, I wit- tention, there is increasing evidence that ad-
nessed eight instances of predator response to ditional costs, such as increased exposure to
playbacks of wood-quail choruses (three in predators, should also be considered in studies
2000, four in 2001, and one in 2002). During of the evolution of communication (reviewed
109 survey mornings (mean = 4.3 social in Gil and Gahr 2002). This may be particu-
groups surveyed per morning), the loudspeak- larly important in birds because the empirical
er was approached by a single predator on evidence for a high energetic cost of singing
four occasions: two gray foxes (Urocyon ci- in passerines is equivocal (Eberhardt 1996,
nereoargenteus) and two Collared Forest-Fal- Gaunt et al. 1996, Oberweger and Goller
cons {Micrastiir semitorquatus). These pred- 2001, Thomas 2002, Ward et al. 2003), and
ators approached the loudspeaker after the re- studies of a nonpasserine. Red Junglefowl/do-
cording had been played from one to three mestic roosters (Callus galIus), show that
times. During 95 capture mornings, the loud- crowing is not energetically costly (Chappell
speaker was approached on three occasions by el al. 1995, Horn et al. 1995). Similarly, cho-
a single predator, one margay {Leopardus wie- rusing in Black-breasted Wood-Quail seems
dii), one Barred Forest-Falcon (Micrastur ruf- unlikely to be energetically costly even
icollis), and one Collared Forest-Falcon, and though it is a year-long endeavor: on any giv-
on one occasion by two domestic dogs {Canis en day, individuals sing for a short amount of
familiaris\ which have been observed to cap- time, perhaps giving only several bouts, each
ture wood-quail in this area). While the forest- less than I min in length (AMH unpubl. data).
falcons approached the loudspeaker after the This is in contrast to the high le\el of singing
recording was played just three limes during effort, in terms ofboth frequency and duration
capture attempts, the margay and dogs re- of songs, observed in many male passerines
sponded after the recording had been played during the breeding season (Welty 1982,
approximately 10 times. In each of these in- Catchpole and Slater 1995). 'Hiis comparison
stances, the behavior ofthe predator suggested suggests that a high metabolic cost aiul li>ss
that it was responding to the vocalizations of time that could be spent foraging or resting
I
rather than something else in the einironment. are not likely for wood-tjiiail. with the excep-
! The two foxes walked directly to the loud- tion of chorusing associated with prolonged
I speaker before leaving the area upon seeing territorial encounters.
'
me; the margay broke through the mist nets 'Hie observations jnesented here suggest
I and pounced on the loutlspeaker; one C’ollared that pretlators eavestlrop on choruses pro-
Forest-E'alcon laiuletl within a lew m of the duced by w()od-t|uail. In my siutly area, a
;
I
170 THE WILSON BULLETIN • Vol. 1J6, No. 2, June 2004
predator responded to recordings on 1.4% of Chapman Memorial Fund, a—nd the Department of Bi-
the 589 surveys or capture attempts. This is ology, University of Miami Maytag Fellowship.
likely to be a great underestimate of the risk LITERATURE CITED
of predation; it is reasonable to presume that
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1313.
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