Home range and extra-court activity in the male Tooth-billed Bowerbird, Scenopoeetes dentirostris (Ptilonorhynchidae)

8 Pages·1994·1.2 MB·

by  Clifford B Frith

HOME RANGEAND EXTRA-COURTACTIVITY IN THEMALETOOTH-BILLED
BOWERBIRD, SCENOPOEETESDENTIROSTMS(PTILONORHYNCHTDAE),
CLIFFORDB. FRITH, DAWNW.FRITHANDGEOFFREYJ. MOORE
Fnlh, C B., Fnlh, D. W. & Moore, G.J. 1994 12 01: Homerangeandextra-court activity
inthemaleTooth-billedho\\erbMScenopo^etesdennrostris(?\i\onoihynchidac).Memotrs
oftheQueenslandMuseumy?0)A47-\5A. Brisbane. ISSN0079-8835
Homerange,timeutilisationandactivitiesoffourmaleTooth-billedBovrabirdsaway from
theiradjacentcourts weremonitored by radio-tracking throughoutIhe 1989display season
inuplandrainforestofnorthQueensland.Threeofthemaleswereknowntobeadults,having
attended theircourts forten ormore seasons. Males spent an average of36ft oftheir time
absent fromcourtsduringpeak displayseasonactivity. The meanhomerangeofmales was
9.5ha, withamean overlapof50%. Median distancestravelled by males from theircourts
forall activitiesrangedfrom40-86m,withamaximumrangeof311-391m. Activitiesaway
(n'in courts included foraging,collectionofleafdecorations directly Irom treesorby theft
fromneighbouringcourts,interactionswithconspecifics,bathinganddrinking.Mostabsen-
ces (60%) were primarily for foraging which represented 83% oftotal time absent with a
meandurationof IRminsperabsence. Some IH%ofabsences, representing1% oftotallime
absent, involvedexclusivenon-foraging activities. Almostail ofthose absences woe oriel
withameandurationof5 nuns. The remaining 22%ofabsences, representing 10%oftotal
limeabsent, fromthecourtinvolvedunknownactivities. Ahsencesfromcourtswereshortcm
duringNovembei,andduringtheearlypartofthemorning(0600-0900h).The implications
ofthesedataarcdiscussed.[J Tooth-hilledBowerhirdhomerany,esiz.*\ timeurilisanonand
activatesanvyfromcourts, Ptilanurhvnchidae,Australia
CliffordB. Frith&Dawn W. Frith, HonoraryResearch FellowsoftheQueenslandMuseum,
'Prkmodura', P.O. Box SHI, Malanda . Queensland4885. Australia, Ceufhey / Mnnrc.
ZoologyDepartment,JamesCook UniversityofNorthQueensland, Townsville, Queensland
481/,Australia;presentaddress.-AustralianAntarcticDivision, Tasmania 7050,Australia,
24June 1994.
Several families of passerine birds include about borne range size, time utilisation and ac-
species that exhibit polygyoous mating systems tivitics of male Tooth-bills away from their
in which promiscuous,competitive and often or- courts Tins paper reports observations on ihe
nate males take nopart in nestduties. In mostof behaviour and movement of four court-owning
these species males spend much of the day at maleTooth-billsusing radio-tracking and simul-
eithersolitaLryorcommunal (lek)displayperches; uWCOUS observation from hides near courts. The
females areattracted tothese sites by thecallsof aims ofthis work were threefold: to identify the
themales andarecourtedby a varietyofdisplays toleofmaleTooth-billsasseed dispcrsers within
(Gilliard, 1969; Snow, 1982; Bcehier & Pructt- tropical rainforest (Moore. 1991); to determine
Jones, 1983, Beehler 1989). The Tooth-billed whether male Tooth-bills spent much time
Bowerhird, Scenopoeetes dentirosnis is one present, butsilent, in the caivopy aboveorwithin
such species (Frith & Frith, 1985, 1993). Males Ihe vicinity Of their court (Frith <fe Fnlh 1994);
of this species establish cleared courts on the and to ascertain home ranges and activities of
forestfloorinareasofsuitabletopography; mean males awaj from thecourts. Thethird aim isthe
nearest neighbour distances in these areas are subjectofthepresent paper
50m (Frith & Frith, in press). Frith and Frith
^(199T4)^found that during peakMa%ctivity male study Area and Methods
u^"1 a" aVCrage °f 0l lhC &dy Thestudyareacomprised SOhaofupland tropi-
(060f)-lWH)h) at courts; court visits averaged* ca raintbrest altitudc c>875m< on lhe Paluma
23mtnsandcourtabsencesaveragedl4mms.Thc , ,
R ,1^00'S, 146°10'E), north-eastern
birds spent more time at their courts during Queensland, 7kni from PalumaTownship, 80km
seasonsofgreater fruit abundance, north ofTowMViUc. Descriptions ofthe Paluma
The behaviour ofmale Tooth-bills at courts is Range study area and its climate appear in Fnlh
&
increasingly well understood (Frith Frith, andFrilh (1994). Halfol the sue wasdivided into
1993, 1994;inpress). However nothingisknown permanently marked 25 X 25m gnd squaresand
148 MI-MOIRSOFTHhOI-'HENSLANDMUSi i M
the remainder was divided into 25 x 50m rec- The radio-tracking team remained at least 30m
tangles; this enabled accurate plotting of loca- distant from the courts ofthe radio-tagged birds
tionsat which thebirds wereobserved. tominimize disturbance to the court owner ot bo
Radio-tracking was undertaken during the other Tooth-bills in the area. The tracking team
consisted of GJM, with the radio antenna and
1989 display season (17-27 October, (6-26
receiver, who followed the bird's signal and
November and 12-22 December)&. Four males marked destinations, and CBF who attempted to
(.from courts 23, 33, 35. 37; Frith Frith, 1994: maintain visual contact with the bird and in-
afin£d. wIe)rweerheancdaeudghwtitinhmaimsettnaeltsbannedaranthdeiarucnoiuqrutes formed GJM ofits location and behaviour in the
twocolour-bandcombination. Males atcourts23 canopy and ol the compass bearing ofsignals.
and 37 had been the traditional owners at those Males were tracked using a Telonics (U.S.A.)
sitesfortenpreviousdisplayseasonsandthemale Tr-2 receiver. To improve reception at close
saiiteco3n3nwa*s5 ufonrha\n1dperdevatiotuhsessteaarstoonfs.thTeh8e9dmiaslpelaayt rmaannguealangdaidnirceocnttiroonlfwiansdinfigttaebdiltiotyt,heanreecnickvier. A
•n and may have been the unmarked owner three element, folding hand held Yagi antenna
of this site forthe two previous seasons (Custom Electronics,U.S.A.) wasusedfordirec-
tion finding. Use ofa small single earphone as-
Each male was monitored for four periods sisted communication between observer and
(0600-0900, 0900-1200. 1200-1500. 1500- tracker; this was necessary because many forays
1800h)dutingOctober,butonlythreemaleswere resulted in adashofup to40Um todetermine the
monitored during November (at sues 23, 35, 37) bird'sdestination.
and December(23,33,37). All maleswereradio- Onceamalehadbeen followedtoadestination,
tracked for a total of 120 hours The first hourof the tree was tagged and, at a later dale, the posi-
the first tracking period (at site 33) was excluded tions of all destination trees were mapped in
fromtheanalysisduetopossible disluibance(see relation to the pre-established grid. On a lew
below) Male 37 lost a transmitter during erne occasions males flew beyond the limits of the
tracking period and, although his conn arrivals study site; in these cases thelocations ofdestina-
anddepartureswere recorded. lii> activities tion trees were plotted by tapeand compass.
from the court were unknown Radio tracking
was also carried out after 2000h, for two 30 Signal strength and consistencywere used as a
minuteperiodsateachcourttoascertainwhether guide lo bird activity and ifthe birdcould not be
the cwnrf roosted above his court. sighted, itspositionwasdeterminedby triangula-
tion. Ifthe signal was strong and consistent, this
Hach male was fitted with a4g Bioirack single usually meant the bird was stationary. A bearing
stageradio-transmitter(SS-I) using a tail mount was then taken from the nearest grid reference
(Kcnward, 1978). Radio-taggedindividualswere point and a second bearing takenat the next gnd
readily identified by the antenna extending reference point to obtam h lis To ieM the ac-
beyond the tail. To assist rapid identification of curacy of this method, calibration transmitters
individualswhenthey wereinthecanopy asmall were placed in irees and the resulting fixes were
amountofcontrasting coloured paint was placed found to be within 5m of the actual transmitter
on the underside tips of the outer tail feathers. position
Rad»o-iraeking was initiated a week -ifiercapture A highly Variable signal, m both strength and
to allow sufficient lime forthe birds toadjust to consistency, indicated the bird was moving In
thetransmiller. thesecases the signal was followed until asiron^
Weestablishedcrypticcanvashidessix metres and consistent signal was obtained and the
from each court two weeks before starting the process was then repeated If foraging, a strong
study. The observer (DWF) remained within the variable signal was obtained as the bird would
hide during each tracking period and all bird change its orientation while moving between
behaviour, locations, departure and return times branches Thesound offalling debris Of fruii
and flight directions were noted. Eachthree hots often a good indicator ofapproximate bird loca-
observationperiodwasstartedcitherten minutes tion within the forest canopy. Ifinteracting with
afterestablishing U\VT* inthehide rjt earlieritlhe other individuals, calls and chase flights were
malereturned tohiscourtandbehavednormally. OJtefl heard
The observer was in constant radio contact with Establishing a final destination using radio-as-
the radio-tracking team andalertedthemassoon sistedsurveillance usually resultedintrackerand
a bird left orarrivedat hiscourt. observer reaching a desitnation some lime after
ACTIVITIESOFTHE MALETOOTH-BILLEDBOWERBIRD 149
FIG. I. Minimum Convex Polygonhomerangeareas(n=636fixes*)for fourmaleTooth-billed Bowcrbirds, based
upontheiradjacentcourts,duringthe 1989displayseason.Numberedstars=male'scourtlocationandnumber.Solid
dots=sightingsofmalesintreecanopy.* male23=202 fixes;33= 148 fixes; 35= 122fixes; 37= 164.
the bird. This problem increased the further the were either observed directly or inferred from
male travelled from his court. In addition, male characteristics of the destination ofthe bird, the
Tooth-bills are well camouflaged and rely on radio signal or sounds from the canopy. Direct
cryptic habits to avoid predation (Frith & Frith, return flights from a destination tree to a court
1993, 1994). For these reasons it was often dif- weredetermined by therapidloss ofasignal and
ficult and sometimes impossible to establish the subsequentrecording ofthe male atthe court
DWF
either the final destination or the activities of a by in the hide.
bird, leavingthereason formany foraysbyabird Many home range estimators are available for
as unknown, and destinations as approximate home range analysis (Mohr, 1947; Southwood,
areas only. 1978; Anderson, 1982; Worton, 1989). Follow-
In this paper absences from courts are classed ing animals using focal sampling results in
broadly as foraging, non-foraging and unknown autocorrelationoflocations(i.e.non-independent
activities. Foragingabsenceswerethoseprimari- fixes). This may create problems in the analysis
lyconcernedwithvisitsto foodtreeswherefruits of radio-tracking data. However, several recent
wereeaten but sometimesbriefnon-foragingac- studies have found that home range estimates
tivities were observed before or after feeding. based on independent versus non-independent
Non-foraging absences did not include visits to locations are statistically indistinguishable
fruiting trees or, the the best ofour knowledge, (Anderson &Rongstad, 1989; Geseetat., 1990).
feeding. Foraging and non-foraging activities As most fixes obtained during this study were
MEMOIRSOFTHEQUEENSLANDMUSEUM
150
TABLE Three-way fixedfactorAnalysisofVariance *examiningthe Variance using urcstn square root
1.
died of month, lime period and individual male on home ningc es- transformedproportions:F=6.36,
tematcs forfourmaleTooth-billed Bowerbirds during peak activity of df. 3 p _ 0.0164). The greatest
the 1989display season. home range overlap wasobserved
between males whosecourts were
—p closest together (Fig. 1, Table 2).
The median distance males
Month * 1.43 0.269 travelled from their courts for all
Timeperiod S V26 320 activities was 59m, with a mini-
individualmale 3 2.31 0.115 mum of 8m and maximum of
MT^omnethpekrioTdimxepMeornitohd e9 00.2326 0993665 391m (Table3). Minimumdistan-
Month h Timeperiod x Bird 16 cesoccurredwhenmalesstoleleaf
Total 39
decorations from a neighbour1s
court or chased offconspecifics a
*- valuesoWainedusingMinimumConvexPolygonmethod short distance from their own
non-random the Minimum Convex Polygon court. Maximum distances oc-
(Morn; 1947; Southwood, 1978) estimator was curred when males flew to a creek to hathc,
used loestimate home rangesize.This method is usually in the middle of the day. The nearest
sufficientlyrobusttodealwithnon-independence Significant body of water was located in a gully
oflocations.Homerangeandhomerangeoverlap about 300m from the courts (Fig. 1).
were estimated using the commercial package
Ranges IV. Time Utilisation
Mostfrequencydistributionsoflimeand space Malesspentanaverageof64%(range56-73%)
use about a court by themale owner were highly of total time (0600-1800h) attending courts
skewed towards the court; therefore the median during peak activity ofthe 1989 display season.
was chosen as the best indicator of the central Upto3%ofthistimepresentmalesweredetected
placetendencyofthedata,ratherthan mean(Zar. above iheircourts by radio signals, but remained
1979). unseen or unheard by the observer in the court
&
hide (see Frith Frith 1994. table 3). In a three
RESULTS way fixed factor analysis ofvariance examining
the efFects of month, daytime period and in-
HomeRange dividual male on the proportion of time spent at
ThemeanhomerangeareaforfourmaleTooth- the court during 1989, there were no significant
bills over the 1989 display season was 9.5ha differences(Table4).Courtattendancelevelsand
time-budgeted activities at courts by the four
(range 6.9-12.5) as determined from a total of
636 fixes obtained away from courts (Fig, I), In malesduring different months (October-Decem-
ber) and during different times (0600-1800h) of
a three way fixed factor analysis of variance
aexnadmiinndiinvigdutahleoenfftehcethoofmmeonrtahn,gedeasyttiimmatee,petrhieorde (tFhreidthay&duFrriitnhg,t1h9is94s)e.asTohnearreesurletpsorotferdaedlios-etwrhaecrke-
were no significant differences (Table 1). Mean ing at courts at night revealed that each male
overlapofthe fourhome ranges was 50% with a Tooth-bill roosted above hiscourt.
range from 23-80% (Fig. 1, Table 2). There was Malesspentanaverageof36% (range27-44%)
a significantdifference in theamountofoverlap of total time (0600-1800h) absent from their
observed between individual males and their courts during peak activity of the 1989 display
nearest neighbours (one way Analysis of season, with a mean duralion per absence of
TABLE2. Percentoverlapofthe homerangesoffour TcAoBurLtsEb1yDfiosutramncaelse(Tmo)otohf-balilllmeodveBomweenrtbsiradwsaydufrriongm
radio-tagged male Tooth-billed Bowerbirds away
peakactivity ofthe 1989display season.
from their courts during peak activity of the 1989
iisplav season Male Number Modtan tMrinun Majrimwr
OfflJWS instance distance distance
Male 3» W 35 37
a 202 BOB 271 w4n
2a3nf3si j0Ma26r6 0m76B.*60- 3U96U42 445574.717 333T7o35tal 1B11264B246 54a560f9,-t.*644 118034...2932 WaMWtD1i..t4t«.
ACTIVITIESOFTHEMALETOOTH-BILLEDBOWEKB1RD 151
TABLE4. Three-way fixedfactor AnalysisofVariance*examining the ACTIVITIES AWAY FROM
effect ofmonth, timeperiodand individual maleon proportionoftime COURTS
four male Tooth-billed Bowerbirds spent at their courts during peak Of 197 total absences from
activity ofthe 1989display season. courts 1 19 were foraging absen-
ces (60%), 35 non-foraging ab-
Treatment df F P sences (18%) and 43 absences
with unknown activities (22%).
Month 2 0.51 0.6091 representing 82.8, 6.8 and 10.4%
Timeperiod 3 12 0.9494
Individualmale a 106 0.3916 of total time absent respectively
Momti < Timeperiod 0.21 0.S700 (Table 5). A foraging absence
Timeperiod * Month 9 0.21 9665
Month N Tim*wood « Biro 16 averaged 17,9mins (range 114-
Total 39 24), a non-foraging absencr
averaged 5mins (range 2.9-13)
'=usingarcsmsquareroottransformedproportiondata. andanabsencewithunknownac
tivities 6.3mins (range 5.1-6.9,
I3.1mins (range 8.4-17.7). The proportion of Table5
total time males were absentand the mean dura- i
During foraging absences the birds were seen
tion of absences were lower during November in destination food trees for67% ofthe time; the
than during October or December, Males spent
remaining time being spent en route to or from
less time at courts during the middle of the day the court (30%) or performing non-foraging ac-
between 0900-1500h (Table5). tivities(3%). Sixty sixofthe 1 19 foragingabsen-
During the first hour (0600-0700h) ofthe first ces were to known food trees. The median
Octobertracking period male 33 cleared a small foraging distances travelled by three males to
subsidiary court some 40m away from his thesetreesrangedfrom 19-42m,butmale37flew
primaryone. Becausethisunusualbehaviourmay much furtherto forage, with amedian distanceof
havebeencaused by banding, transmitterattach- 119m.
mentorboththerecordsfromthishourhavebeen During a foraging absence males usually flew
excluded from analyses. During subsequent Oc- directly from the court to a food tree. On eight
tobertrackingperiodsthismaleoccasionallyHew occasions, however,acourt owningmalephased
over, and perched briefly above, the rudimentary aconspecificfromhiscourtbeforecontinuingon
court (<3% of total time absent from his estab- toafoodtree(secbelow). Malesalsooccasional-
lished court), Male 33 spent more time absent ly flew directly towards a creek (before or after
fromhiscourtthantheotherthreemalesandMale feeding)whereitwasassumedtheywenttobathe
37 spentless time absent(Table 5), but differen- or drink, but trackers were only able to visually
ces between the four males were not significant confirm this twice. Most times (86% offoraging
(X2= 3.78, P> 0.02). absences) the bird flew directly back tothe court
TABLE 5. Activities performed by four individual male Tooth-billed Bowerbirds during absences lmm iheu
courtsoverpeakactivityofdisplay season.
ABSENCES: FORAGING NON-FORAGtNG UNKNOWNACTIVITIES TOTAL
Male Hour* Numb* %of Moan Number %of Mean Number %of Mean Number %o( Mean
ofradln- or time mins© of bma mina© of bme mineQ of totaltime mini©
traolnno. absences absent absence sbaancaa absent absence absences absent absence absences ebsent absence
Malt
23 36 43 84.6 161 5 79 13.0 12 T-S 11 60 13.6 379
33 23 26 008 212 5 37 48 5 5.5 69 36 169 «*1
»n: 2346 2210 6869..83 21431 167 a5.2e 25..19 B4 254..90 65..96 6302 17847 239T.02
Month
October 47 38 80.6 196 18 59 41 16 106 «JB n 13.4 34,1
November 36 :js 78« 139 13 90 43 tl 12.6 4fi H 97 280
December 36 45 87.5 19,3 4 35 61 1? CO 76 61 t62 46
Time
0600-0900 29 32 76.5 11.4 ie 103 11 10 135 6.3 01 62 27.4
01920000--11520000 3300 IaI GB5011 220290 f4i 83.34 1601J 1<3S 111153 65.74 vu.. 116511 440110
1600-1800 30 30 77.8 1S2 i 62 43 5 61 78 44 14 t 346
TotaVmaana/V 119 119 B2.B 17.9 35 66 SjO # 10.4 *3 197 131 $.•
152 MEMOIRSOFTHEQUEENSLANDMUSEUM
but on 15 occasions (14% offoraging absences) Guinearainforests.Thesespecies wereknownor
a leafdecoration was collected during the return presumed to involve promiscuous males. Males
(rip. Tt is possible that undetected activities oc- of species with a predominantly arthropod diet
curred during flights between courts and food were found to be territorial while males of
trees. predominant frugivorous species were non-ter-
Of the 35 non-foraging absences 12 entailed ritorial. Lack of territoriality in predominant!>
collection of a leaf decoration from a tree (3 frugivorous passerine species is considered to
leaves)orfromanothercourt(9leaves), 12were result from the fact that tropical fruits are
visits to the forest canopy above a neighbouring economically undefendable (Lilt, 1976; Beehler,
&
courts, and 11 involved the male court-owner 1989; Beehler Pruett-Jones, 1983).
chasingaeonspecificandthenreturningimmedi- Duringthe 1989display season themean home
atelytohisowncourt{seebelow).Theft involved rangesize ofmaleTooth-billswas 9.5haand the
a male flying directly to a neighbouring court, median distance travelled fromcourts forall ac-
quickly and quietly stealing a leaf from it, and tivities was 59m. Comparabledata on the breed-
returning directly to his own court. Leaf theft ing season home range of other tropical
represented 0.5% of total time absent from the frugivorous birdswhich display at focal sites are
court, with a mean duration of 1.5minspertheft. scarce. Pruett-Jones & Pruett-Jones (1988)
The 12 visits lo a neighbouring court were brief reported that the home range of one adult male
and involved the court-owner flying directly to, Blue BirdofParadise.Paradisuea rudotphi, was
andperchingquietlyabove,hisneighbour*scourt 4.7ha over the season, about half the size ob-
for a short period (mean duration = 3.3mins), served in male Tooth-bills. Display trees of the
possiblywiththeintentionofstealinga leaf".This formerspeciesaremuchmorewidelyspacedthan
behaviour wasperformed byall four males are the courts of Tooth-bills (220m vs 50m
Males were seen to chase conspecifics away respectively). Blue Birds of Paradise are not as
fromthecourton 19occasionsflyingontoafood exclusively frugivorous through the breeding
treeaftereightsuchchasesandreturningdirectly season as are Tooth-bills (ef. Beehler & Pruett-
back to thecourt after 11 of them. Threechases Jones, 1983) and this, together with a possible
were in pursuit of a presumed female (having greaterabundanceoffoodneardisplaysite*,may
previouslybeendisplayedto). Itispossibleother account for differences in home range sizes be-
chases were after a neighbouring male. On one tweenthesesimilarsizedspecies.Itisnoteworthy
occasion a leaf was stolen by a marked, neigh- thattheall-purposeterritoryofthreemaleSuperb
bouringmalejustasMale37relumedlohiscourt Birds of Paradise, Lophorina xuperba a species
The latter male immediately chased the thiefto with only 24% fruit in its diet, averatged 1.5ha
the thiefs court, about 7(>m away, where he [range 1.2-1,7) (Beehler & Pruett-Jones, 1983).
stayed briefly before returning to his own court The availability of fruit in time and space may
wilhouL a leal. He was, however, subsequently thereforehave majoreffectson bothmaledisper
seen to steal frnm that particular neighbour's sion and home range.
court.
Male Tooth-bills do not move far from their
Interactions between conspecifics were ob-
served away from thecourt. On fouroccasionsa courts and, as would be expected, males a', an
explodedlek exhibit considerableoverlap(mean
malelefthiscourtandflewtowhereotherTooth- =50%-)ofhome ranges Those withclosercourts
bills were heard displaying, either above of on
another a court. On one occasion Male 35 was show the greatest overlap, and males from dif-
ferentcourts wereobserved tobathe in the same
seenculling anddisplaying loanassumed female
nearacreekthatwasabout300m from hiscourt. portions ofcreeks and to feed in the same trees.
Althoughdistancesincurredintravellingtobath-
l")titwoivl;im his twobirdswereseenfacingeach ing and drinking locations, or those associated
otherinafoodtree, facetoface,withconspicous-
with leaf thefts, are likely to remain constant
lv sleekedplumage and agitated vocalisations. across years this will not be true of distances
travelled to and from feeding locations. These
DISCUSSION'
latter distances will vary between years as dif-
ferent individual trees or species of tree fruit.
&
Bcchlcr Pruett-Jones(1983)reviewedavail- Seasonalenvironmentaldifferences,inparticular
able information concerning the spatial dispcr- fruit crop size, affect the length of Tooth-bill
ftion of adult males of nine polygynous bind of display seasons and the proportion of time that
paradise species (Paradisacsidac) from New males attend courts (Moore, 1991, Frith& Frith,
ACTIVITIESOFTHE MALETOOTH-BILLED BOWERBIRD 153
1994), Fruit crop was poor during the 1989 dis- meal eaten or the distance travelled to the food,
playseason (Moore, 1991). Consequently, males males almost invariably return directly to their
spent a greater proportion (36%) of their time courtinordertodefenditfromleafstealing n-
3bscnt from courts, to feed, during the 1989 andtocal1 anddisplay. Ineffect,maleTooth-bills
season than during the 1980season (21%) when attempt to maximise their time at their c\
fruit was abundant (FrithSc Frith, 1994), During (Moore, 1991). They can achievethis, however.
the exceptionally dry 1979 season an extremely only by utilising a food resource that is freely
poor fruit crop resulted in males spending even available and unable to be defended, namely,
moretime(48%)awayfromcourts(Frilh& Frith. fleshy fruits. Snow (1976) considered a
1994). predominantly frugivorous diet one of the main
All theobserved movementsaway fromcourts pre-conditions to a mating system lacking pair
appeared to entail direct purposeful flights to bond and biparcntaJ brood care in which males
food, wateror leaf(court decoration) resources. spendmuch lime attendingamidefendingatradi-
Activities such as Interactions with conspeeifieN tional courtshiparea.
or the collection of leaf decorations that were
ACKNOWLEDGEMENTS
observedaway fromcourts, during both foraging
andnon-foragingabsences, wereextremely brief
(Table 5). Most absences were forforaging, rep- CBFand DWFthankGJMandthe Department
resenting 83% of total time absent with a mean of Zoology, lames Cool University oi North
duration of IX ruins (Tabic 5). Mootc (1991) Queensland foruseof radio-trackingequipment.
found that Tooth-bills tended to forage more in GJM thanks Profesxor Rhoftddd Jones mid Dl
food trees closer to the court than those flirlhtf AnncmancWattlorreviewinginitialdraftsofhis
away and as a result shorter foraging absences thesis manuscript and the Commonwealth
were more frequent than longer ones- Median Postgraduate Research Awards and the
distance travelled from courts exclusively for Australian Research Council for financial assis-
foraging at food trees was 32m (median range tance for this project which formed pan of his
27-1 19). Male 37 flew much further than the PhDstudyonseeddispersalbymaleTooth-billed
otherthreemalestoforage,oftenvisiting fruiting Bowerbirds. Glen Ingram and PeterDwyerkind-
trees some 380mtotheeastofhiscourtthatwere ly provided constructive criticism ofa draft thai
not visited by the other males studied <Fig. I). improved thiscontnbulion.
Whilemalesotherthan thoseofthisstudy doubt-
LITERATURECITED
lessfediflthesetreestheobservationsuggestsuV
possibility that males on an exploded Ick may
travelgrcatcrdistanecstoutiliserichfoodresour- ANDERSON, DJ. 1982, Tfte home nit r nun
ceswherecompetition may be less. It is possible, parametricestimationtccliniL|tf.. hctiliigy63:I'M
however,that Male 37 alsofed in this areadueIQ ANDE1R1S2,ON, Q£. & KONCSTAD, OJ I9K9. Hon*
the local accessibility ofthe creek (sec Fig.I ). rangeestimates ofred-tailedhawks based on ran
Donaghey (1981) presented the only com- dom and systematic relocations. Journal of
parabledata. He found thatfive rainforest-dwell- WildlifeMangement 53:802 807
ing male Satin Bowerbirds. Ptilonorhytichus BEEHLER,B.M 1989.Thebirdsofparadise.Scientific
yiobceus, mostly foraged forfood within50mof American 261:1 17.\2\
theirbowers(83%of83 foragingrecords)during BEEHLER. B. M & PRUETT-JONE& S. G.1983
the breeding season of October-December. He Display di-vpcrsion and diet Ol birds ol paradise,
obtained almost identical results for four wood- a ;omrvirison ofnine species. Behavioural Ecol
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