The Auk 111(1):131-142, 1994

EFFECTS OF BAND ON SURVIVORSHIP, BODY CONDITION AND REPRODUCTIVE EFFORT OF FREE-LIVING AUSTRALIAN ZEBRA FINCHES

RICHARD ZANN Departmentof Zoology,La TrobeUniversity, Bundoora, Victoria, 3083 Australia

ABSTRACT.--Indomesticated laboratory Zebra Finches (Taeniopygiaguttata), leg bands of certaincolors affect mate selection,parental effort, reproductivesuccess, sex ratio of offspring, and survivorship.I tested the effectsof these same colorson survivorship,body condition and reproductiveeffort of free-living Zebra Finchesover severalbreeding seasonsat two coloniesin northern Victoria,Australia. At the "Cloverlea" colony,adults of eachsex received either "attractive"or "unattractive"color bands.Nevertheless, survivorship to 12 months was not affectedby band color nor was there compellingevidence (mass, bill color and molt) for deterioratingbody conditiondue to reproductivecosts; there were no sexdifferences in survivorship.Reproductive effort eachbreeding season in thesefree-living birds may not be as great as that in some laboratory populationsbecause in nature the seasonis shorter and the intervalfor recoverycorrespondingly longer. In contrast,at the "Danaher"colony, where birds had unique color combinationsof three bands(plus one metal band), a retrospective analysisof four years of data showed that there were significanteffects of band color on reproductive effort of females;they laid more eggs if mated to males having a single band (attractivecolor) in their combinationthan if mated to maleshaving a single - band (unattractive color) or bands of other (neutral attractiveness).They laid an extra clutch, but this did not result in significantly more fledglings and independent young being raisedby the pair. There were no band-coloror sex effectson survivorshipof adults at this colony. There were no obvious biases in the allocation of band colors or identificationof breedingpairs that might explainthe extra-clutcheffect. The finding on red- bandedmales is largely consistentwith that describedfor domesticatedZebra Finches, where femalesmake a differential reproductiveallocation in responseto their partner'sband color. No similar effectswere found for female band color where, contrary to expectation,females with (attractive)bands had significantly fewer fledglings than did femaleswith color bandsof neutral attractiveness.The overall conclusionis that colorbands do not significantly affect the behavior of wild Zebra Finches, but it would be wise to omit red bands on males where possible.Received 18 August1992, accepted 8 December1992.

COLOREDLEG BANDS affect mate selection (Bur- cluded that the potential of leg-band colors to ley 1981, 1986a, Burley et al. 1982), parental create biases in behavioral studies of natural investment (Burley 1988a), reproductive suc- bird populationsmay be overestimateddue to cess(Burley 1986b),sex ratio of offspring(Bur- many confounding effects. ley 1986c)and longevity (Burley 1985) in lab- A number of studies have investigated the oratory stocksof domesticatedAustralian Zebra effects of leg band color on behavior of wild Finches (Taeniopygiaguttata castanotis).The fact birds. Some a posteriorianalyses of long-term that wild-caught female Zebra Fincheshave the banding data have demonstrated negative ef- same band- as domesticated fectsof band color on reproductive success(Ha- ones(Burley 1988b)strengthens Burley's (1985) gan and Reed 1988), whereas others have found warning about possibleartifacts and biasescre- no effect (Beletsky and Orians 1991, Weather- ated by color marking of individuals in wild head et al. 1991). Similarly, findings are mixed populationsof Zebra Finchesand, by implica- with a priori designs:Metz and Weatherhead tion, other avian species.Conversely, Ratcliffe (1991, 1993) found negative effects, whereas and Boag(1987) found that, under experimental Cristol et al. (1992) found no effect. The influ- conditions promoting intermale competition, ence of leg-band colorson behavior appears to leg-bandcolors of their domesticatedlaboratory vary accordingto species,in particular whether Zebra Finchesdid not affect a male's ability to the color matchesone found on the bird's plum- compete for nest sites and females; they con- age or soft parts; if so, it may modify visual

131 132 RICHARDZANI• [Auk, Vol. 111

communication processeswith other members out the year, and continued to do so during the of the species. breeding season(Zann 1985). Consequently, if To investigate effects of band color on be- birds undergoreproductive stress resulting from havior of wild Australian Zebra Finches, I stud- reproductiveeffort it is feasiblethat feather re- ied the effectsof leg-bandcolors in two adjacent placementmay be slowed or suspendedduring breeding colonies("Cloverlea" and "Danaher") the period of stress.Reproductive stress might in the southeasternpart of the Australianwide also affect bill color, which becomes less red distribution of the species.In the color-band over the breeding seasonin wild Zebra Finches experiment at Cloverlea I tested specificallythe (Burley et al. 1992); in domesticated Zebra effect of band colors on body condition and Finches bill color declines during a single survivorship. All males received either red breeding cycle, and there is an overall decline bandsor light-green bands,and all femaleswere with prolonged breeding (Burley 1985, Burley given black or light- bands. The bands et al. 1992).Therefore, to detectchanges in body (supplied by A. C. Hughes, Middlesex, En- conditiondue to reproductivestress, I measured gland) were the same size, shade and material differences in mass, molt and bill color before (celluloidplastic) as those used by Burley(1981, and after breeding in birds of each color-band 1985, 1986a, b, c, 1988a) in her studies of do- type trapped at Cloverlea. mesticatedpopulations, where she found that The secondcolony in which the effectsof leg- red bands (attractive to females relative to un- band colorswere investigatedwas the Danaher banded males) conferred significantly greater colony. The study was not designedwith this survivorship(89 vs. 40%) on male wearersthan specific purpose in mind. Rather, it was de- did light-green bands (unattractive to females); signed to investigategeneral aspectsof behav- similarly, females with black bands (attractive ior and population dynamics;here birds were to males) lived significantly longer than fe- given unique combinations of color bands for males with light-blue bands (unattractive to recognition of individuals. Survivorship and males). Birds with bands of other colors were reproductive performance of many pairs was indistinguishable in attractiveness from un- monitored each breeding season. These data bandedbirds. Consequently,these colors were were analyzed,a posteriori,according to whether assumed to be neutral in effect. In order to test the partnershad attractivebands (red and black), this finding in a natural population I predicted unattractive bands (light-green), or neutral col- that, all things being equal, the red-banded or bands; however, no unattractive light-blue males and black-banded female Zebra Finches bands were placed on females in this colony. would havea higher survivorshipat the Clover- lea colony than their counterparts with light- METHODS green and light-blue bands. Survivorship was estimatedfrom the number of birds recaptured Color-bandexperiment.--Members of this colony 12 months or more after banding. nested and roosted in a tall windbreak on a wheat/ Burley (1985) postulatedthat an asymmetry sheep property (Cloverlea; 36ø09'S,145ø18'E) in the northern portion of the stateof Victoria and had oc- in reproductive effort and its associatedcosts cupiedthe site sinceat least1981 when I first discov- between the partners of the breeding pair ac- ered it. Zebra Finches were present each visit and counts for the differential effects of band color breeding normally ran for eight months, from Sep- on survivorshipof domesticatedZebra Finches. tember(austral spring) to April (australautumn; Zann Differential parental expenditure arises when and Straw 1984). The banding experiment ran from the parent with the attractive band color has a January 1987 through September 1989, and covered lower per-offspringinvestment than its lessat- two and one-half breedingseasons--the second half tractive partner (the differential-allocationhy- of the 1986/1987 season, and the whole of the 1987/ pothesis;Burley 1986b);the different costsdi- 1988 and 1988/1989 seasons. Birds were captured one day each month (except rectly affecttheir respectivelife spans.If free- for the months of May and August 1989 when no living Zebra Finches also incur reproductive birds were trapped) at a walk-in trap baited with a costsduring breeding, these may be reflected weekly ration of commercialseed. The assignmentof in massloss and slow feather replacement over band colors was random. Unbanded birds were this period. Zebra Finchesat a neighboring col- grabbed"blind" from the holding box and allocated ony ("Padgett";3 km eastof Cloverlea)replaced red or light-green bandsif they were males,but black remiges in a slow, continuousmanner through- or light-blue bandsif they were females.A few im- January1994] Bandcolor Effects in WildZebra Finches 133 matures were banded if their sex could be positively her"; 36ø09'S, 145ø26'E) 6.7 km east of Cloverlea. All determined; otherwise, they were released with a birds were given unique combinationsof three color metal band only. The allocationof band colorsalter- bands in addition to the uniquely numbered metal nated between successive birds of the same sex so that band. Birds were trapped at two baited (ad libitum) equal numbers of the color treatments were made. walk-in traps every two weeks during the breeding Three bands of the same color were placed on each seasonand monthly otherwise.The projectbegan in bird togetherwith a fourth, uniquely numberedmet- March 1984 and concluded in June 1989, although al (alloy) band; two bandswere placed on each leg trapping and banding continue on an irregular basis. with the metal band always uppermost in order to Only sevenband colorswere approvedby the Aus- expose the colored bands as much as possible. Red tralian Bird and BatBanding Scheme: red, light-green, bands, which fade faster than other colors, were fre- black,dark-blue, , orangeand mauve.This gave quently replacedwith new ones. 1,372 unique combinations with the metal band at Eachbird was aged and sexedby its externalmor- different positions. Combinations with three , phology (Zann 1985,Burley et al. 1989)and weighed three ,three blacksand three dark-blueswere to the nearest0.I g. The color of the dorsalsurface omitted at the outset to avoid the possibility of un- of the upper mandiblewas scored with Munsell chips desirableeffects on survival and fecundity described in the manner describedby Burley and Coopersmith by Burley(1985) for domesticatedZebra Finches. Light- (1987),and transformedinto a singlescore using the blue bands, which are unattractive to domesticated weightedmethod devised by Burleyet al. (1992),where males when placed on females, fade too fast in the the redder, brighter and darker bills have a higher wild and were not approvedby the BandingScheme. Random numbers were not used to allocate band score than less red, paler bills. Molt of primaries of the right wing was scoredin the numerical manner combinations, but triplets of bands were chosen devisedby Miller (1961) and Ashmole (1962). My "blind" from a list of combinationsprepared before research assistant,who took 90% of all measurements, the study began, and the fourth band of the combi- was unaware of the hypothesesbeing testedon bill nation was added before a banding sessioncom- color,mass and molt. Survivorshipof adultswas mea- menced.This meantthat only sevenbirds banded in suredat 12 monthsafter initial captureand banding, successionhad the same combinationon one leg. a time interval sufficient at least for one or more Trapped birds were grabbed"blind" from the hold- breeding attempts.No attempt was made to monitor ing boxand combinationsapplied irrespectiveof sea- breedingperformance of pairsat this colonybecause son, trap site, age, sex or kinship. The metal band, of problemsin recognizingindividuals and observing which served as a "first master," was located on the nests. top left leg at the startof the study,then bottomleft, The effectsof reproductiveeffort on bill color, mass, then top right, and then bottom right as the unique and primary molt in the Cloverlea birds were assessed triplets of the seven colored bands were used. by comparingthese measuresbefore and after an in- Over the four breedingseasons, 303 breedingat- terval of at leasttwo months (range 2-8 months,me- tempts resulted in completed clutches that reached dian 3 months)of the breedingseason. The interval the incubationstage and, in 150cases, it waspossible dependedon when individualswere recaptured.As to determine from observations at the nest the color breedingwas not monitoredat this colony,there is bandsof both parentsmaking the attempt. The re- no direct evidence that breeding was actually at- productiveperformance of theseparents was studied; tempted by the banded subjects,but previous work nestswhere one or both parentswere unbandedwere at this and neighboring colonies(Zann and Straw ignored.Where the clutchdid not sufferpredation it 1984)suggests that mostbirds would be breeding and was possibleto estimatehow many young reached at least several clutches would be laid in this interval. fledgingage (18-20 daysposthatching); in practice, If the bird was first bandedas an adult during the this was taken as the number of young bandedat 12 breedingseason, the first scores(time I) for bill color, to 14 daysof agebecause handling after this age re- massand molt were taken from that point and com- suitsin forcedfledging. The numberof independent pared to those taken at least two months later or those young (older than 35 days)was estimatedby recap- at the end of the breedingseason (early April) if the ture at the walk-in traps.Breeding was attempted by bird continuedto residein the colony (time 2). If 144unique pairs(27 involved male re-pairingand 23 bandedin the nonbreedingseason, the firstscore was femalere-pairing) formed by 122 malesand 123 fe- taken from late August,just a few weeksbefore the males.For the majorityof pairsthe numberof eggs, breedingseason began. In this way the effectsof non- fledglingsand independentyoung were determined reproductive episodesover the interval of measure- for the "lifetime" of each parent in the colony. In ment could be minimized. If birds bred in more than some cases these values will be less than those for one season,only the first data were included in the the true lifetime of each parent becausesome birds analysis. may have bred elsewhere, either before arrival at the Four-yearpopulation study.--The secondcolony, was colony, having immigrated as adults, or after they locatedon anotherwheat/sheep property ("Dana- disappearedfrom the study site. 134 R•c•a• ZANN [Auk, Vol. 111

TABLE1. Survivorship of adult male and female Ze- Otherwise, nonparametricmethods were employed. bra Finches by band color expressedas number All statisticswere computed by JMP (SAS Institute recaptured12 monthsor more after banding. 1991) or SAS (vet. 6.06; SAS Institute 1990), and all probabilities were two-tailed. Twelve months after banding RESULTS Number of Not bands and Recap- recap- Sex color tured tured G-test a Survivorship.--AtCloverlea there was no sig- nificant difference in the recapture rate 12 Cloverlea b months or more after initial banding of adults Female 3 black 13 32 for either sex or band color (Table 1), nor did Female 3 light-blue 10 44 1.15 Male 3 red 11 35 recapture rate differ significantly between the Male 3 light-green 10 36 0.06 sexes(G = 0.004, df = 1, P = 0.95). The number Danaher c of birds recaptured was the outcome of two in- Female 1-2 black 5 55 distinguishable effects,emigration and mortal- Female 3 nonblack 9 111 0.04 ity; however, there is no reason to believe that Male 1-2 red 13 50 band color would affect the former. Male !-2 light-green 4 35 1.98 At the Danaher colony there was no signifi- ' df = 1. Two-tailed test. None significant (P > 0.5). cant difference in the recapture rate of males "Color-banding experiment at Cloverlea, where each bird also had uniquely numbered metal band. 12 months or more after first banding as adults ßFour-year population study at Danaher,where eachbird had unique among those that had one or two red bands in color-bandcombination and uniquely numberedmetal band. their unique combination or those with one or two light-green bands (Table 1). There were no Males had a mean of 2.19 _+SD of 1.85 breeding black/blue contrasts made with females at this attempts(range 1-6) and females1.96 + 1.45attempts colonybecause the blue-bandallocated here was (range 1-11). However, the number of unbanded dark-blue rather than light-blue. Apparently, young trapped suggestssome successful attempts went theseare neutral in attractive effectwith respect undetected;consequently, these are minimum life- to unbanded females, in contrast to the unat- time values. We found that 90% of birds bred in one tractive light-blue bands used at Cloverlea (N. seasononly then disappeared, 9% bred in two seasons, and 1% in three. Therefore, mean attemptsper life- Burley pets. comm.). When black-banded fe- time are only slightly greater than attempts/season. maleswere comparedwith femalesbanded with Mean clutch size was based on the number of eggs colorsother than black, there was no significant in a completed clutch that reached the incubation difference in survivorship to 12 months (Table stage. 1). There were no significant differences in re- High levels of brood parasitism (11% of offspring capture rate between the sexesof all color-band in February1988) and low levels (2.4%)of extrapair types over 6.5 years of the banding study at copulationat this colony (Birkheadet al. 1990) meant Danaher (31/277 females vs. 47/337 males; G = that the parents identified at the nest may not nec- 1.14, df = 1, P = 0.29). Thus, there were no essarilyhave been the genetic parents of the young detectable differences in survivorship due to they were tending.The evidencefor a pair bond was based on joint nesting activity. The date the bond sex or color band. However, recapture rate was began was arbitrarily taken as the date the first egg significantly higher at Cloverlea (44 / 191 recap- of the first attempt was laid, and the date the bond tured vs. 78/614 recaptured at Danaher; G = wasterminated was taken asthe date the young fledged 11.02, df = 1, P = 0.0009), possibly becauseof from the last breeding attempt the pair made in the a lower predation rate or less frequent human colony. Alternatively, if the pair were seen at the interference. walk-in trap after the last breeding attempt, the last Bill color, mass and molt.--Bill-color scores fell date they were observedtogether was taken as the (i.e. became less red) significantly over the termination date. None of 50 re-pairings occurred breeding interval in females;changes in males while the first partner was still found in the colony, with light-green or red bands were not signif- so I assumethat all pairings were serially monoga- mous. Where a bird had more than one partner, the icant (Table 2). There were no significant color- band effects on bill color before or after breed- mean duration of the bonds was used. Parametricstatistics have been used where possi- ing for either males or females. As expected, ble, but only if data could be successfullynormalized male bill-color scoreswere significantly greater and significant differences in variances removed. than those of females before (Wilcoxon two- January1994] Band-colorEffects in WildZebra Finches 135

TABLE2. Effectsof leg-band color on changes in bill color, mass and molt of adult Zebra Finches over a breeding interval beginning at t! and ending at t2. Medians with interquartile ranges in parentheses.Bill- color scoresare transformed totals of weighted Munsell measuresof , chroma and value (Burley at al. 1992). Molt scoresare in ordinal units where: (0) an old feather; (1) a missing feather or new pin; (2) new feather one-third grown; (3) new feather two-thirds grown; (4) new feather nearly fully grown; (5) a new feather fully developed.

Males Females

Red-banded Green-banded Test • Black-banded Blue-banded Test •

Bill color tl 21.8 (19.8-21.8) 21.8 (21.2-21.8) 0.70 17.3 (16.5-17.8) 17.3 (16.5-17.3) 0.01 t2 21.4 (20.9-21.8) 21.5 (21.0-21.8) 0.009 16.5 (15.9-17.2) 16.5 (16.5-17.3) 0.45 n 30 24 28 35 S -value b - 3.0 13.5 65.0 * 95.0* *

Mass tl 12.4 (11.7-12.7) 12.3 (11.7-12.9) 0.24 12.6 (12.1-13.1) 12.8 (12.3-13.3) 1.06 t2 12.3 (11.8-12.9) 12.7 (12.0-13.2) 1.21 13.3 (11.9-13.7) 13.0 (12.5-13.2) 0.17 n 30 24 26 34 t-value c 0.47 - 1.90 1.58 1.06

Molt (t2 - tl) 7.0 (5.7-9.3) 6.2 (3.6-7.9) 1.50 5.7 (4.0-6.9) 5.8 (4.2-8.3) 1.09 n 27 20 24 32

*, P < 0.05; **, P < 0.01; other values not significant (P ,> 0.05). Wilcoxon two-sample test (z) for bill color, and Student t-test (t) for massand molt. Wilcoxon signed-rank matched pairs test. Paired t-test.

sample test, z = 8.88, P = 0.001, n = 54 and 63) Danaher colony (for which data on lifetime re- and after breeding (z = 9.30, P = 0.001). There productivesuccess were available)were allo- were no significant changesin massover the cated to three groups: those with at least one breeding interval for either sex,nor were there red band in their combination; those with at any significant within-sex band effects (Table leastone light-greenband; and thosewith col- 2). Femaleswere significantlyheavier than males ors other than red or light green. Nine males before (t-test, t = 2.82, df = 112, P = 0.006) and had both red and light-green bands in their after (t = 3.32, df = 112, P = 0.001) the breeding combinations and were excluded from the anal- interval. ysis on the assumptionthat the predicted an- Birds continued to grow primaries through- tagonisticeffects may not necessarilycancel each out the breeding period at a rate of about one other out. By chanceno male in the data set primary per month, but there was no significant had two red bandsor two light-green bandsin difference among the band-color types within its color combination. each sex (Table 2); females, however, molted at There wasno significantheterogeneity among a slower rate than did males, but this does not the three classes of male band colors for the reach 5% significance(t = 1.898, df = 101, P = numberof youngfledged and the numberraised 0.060).Thus, over a breedingepisode three mea- to independence,but there was highly signif- suresof condition that might reflect reproduc- icant heterogeneityin the number of eggslaid tive costs showed no differential effects due to by their females(Table 3). Mates of red-banded band color, but fading of bill color and slower maleslaid significantlymore eggsthan did the primary replacementsuggest that femalesmay matesof males with a light-green band (Wil- lose body condition more than males; this is coxon two-sample test with continuity correc- probably due to their greater reproductive ef- tion of 0.5, z = 3.11, df = 1, P = 0.002) and mates fort which, nevertheless, failed to lead to any of males with neither red nor light green (z = significantloss of mass. 2.88, df = 1, P = 0.004). There were no signif- Reproductiveperformance by males.--To assess icantdifferences in eggnumbers laid by females the effect of band color on reproductive per- mated to males with bands in the last two cat- formance, the uniquely banded males at the egories(z = 0.40, df = 1, P = 0.69). 136 RICHARDZA•q•q [Auk,Vol. 111

TABLE3. "Lifetime" reproductiveperformance of male Zebra Finchesby leg-bandcolor (n in parentheses). Medians with interquartile ranges in parentheses.

Male bands included

Red.' (35) Green b (35) Neither c (34) Testd Independent young 1 (0-3) 0 (0-0) 0 (0-3) 1.43 Fledglings 4.5 (2-9) 4 (0-5) 3 (0-6) 2.57 Eggs 11 (6-15) 6 (5-10) 5 (4-11) 11.86'* Clutch sizee 5 (4.6-6) 5 (4.5-5.2) 5 (4-5) 5.20 Number of clutches 2 (1-4) 1 (1-2) 1 (1-2) 10.12'* Pair-bond duration 81 (55-135) 51 (28-108.5) 54.5 (25-104) 5.08 ß' One metal band, one red band, and two other colorsexcluding light green. • One metal band, one light-green band and two other colorsexcluding red. ' One metal band and three of followingcolor bands: , white, black,dark blue or mauve. "Kruskal-Wallistest for ANOVA by ranks(chi-square approximation; SAS ver. 6.06 1990),df = 2. **, P < 0.01;others not significant(P > 0.05). ' Number of eggslaid/number of nonpredatedclutches that reachedincubation stage.

Although females of red-banded males tend- because there were more smaller clutches in the ed to lay larger clutches this failed to reach 1986/1987 seasonand more larger clutches in significance (Kruskal-Wallis X 2 = 5.2, df = 2, P the 1988/1989 season.Correspondingly, there = 0.074;Table 3); however, there was significant were also significant differencesin the propor- heterogeneity among the three groups in the tion of nesting attempts (at least one egg laid) number of clutcheslaid by their mates (X 2 = made over the four seasons, with fewer in the 10.12, df = 2, P = 0.006; Table 3). Females of 1986/1987 season and more in the 1988/1989 red-banded males laid a median of two clutches season (G = 33.67, df = 3, n = 476, P = 0.0001). whereas females of light-green-banded males The meannumber of breeding attemptsper pair and maleswith neither red nor light green laid for the first two breeding seasonswas 1.5 at- a median of only one clutch; these differences tempts,whereas 2.0 attemptswere made for the were highly significant (z = 2.93, df = 1, P = last two seasonsof the study. 0.003, and z = 2.49, df = 1, P = 0.013, respec- Over the four years of the study there were tively). There was no significant difference in no significant differencesin the proportion of clutch number between femalesof light-green- the three color-bandcategories (red, green, nei- banded males and those of males with neither ther) allocated to males that constituted the data red nor light-green bands (z = 0.26, df = 1, P set (G = 11.24, df = 6, n = 115, P = 0.081; Table = 0.78). 4) althougha disproportionatenumber of green Even though males with red bands did not bands were allocated in the 1988/1989 season survive longer in the colony than those with (11 green, 4 red and, 3 others). This did not lead light-green bands (Table 1), there was a sug- to any significantdifferences in the proportions gestion that they remained paired for longer; of males in the color categoriesthat provided however, this did not reach significance(Krus- breeding performancedata in each of the four kal-Wallis, X 2 = 5.84, df = 2, P = 0.08; Table 3). seasons (G = 2.32, df = 4, n = 112, P = 0.89; It is possiblethat the extra clutch laid by fe- Table 4). Finally, there were no significantdif- males of red-banded males may not be a con- ferences in proportion of the three band-color sequenceof band color per se, but arises from categoriesallocated by age (-<35 days, 36-100, artifact(s) associatedwith banding, or with and >100 days)at banding (G = 7.11, df = 4, n identification of breeding pairs. For example, = 112, P = 0.13). In sum, there were no obvious by chance,more red bands may have been placed biases in the allocation of the band colors, nor on malesduring goodseasons than bad seasons, in data collectionthat might have producedthe and these males would have gone on to father significantdifferences in egg numbersby male more eggs that season.Indeed, there were sig- band type. nificant differencesin the overall reproductive Reproductiveperformance byfemales.--Forty-two performance over the four breeding seasons. of the uniquely banded femalesthat bred dur- The proportions of clutches(n = 303) of differ- ing the study had one or two black bands in ent sizes(3-7) differedsignificantly among sea- their combinations and 63 had no black bands. sons(G = 30.76, df = 12, P = 0.002), principally There was no significant difference in perfor- January1994] Band-colorEffects in WildZebra Finches 137

TABLE4. Number of males by color-band combina- ther red nor light-green bands;G = 2.04, df = tion that contributed "lifetime" reproductive per- 2, P = 0.36; 1/9 males with both red and light formancedata during four yearsof study:(1) season males were first caught and allocated color bands; greenalso repaired). On re-pairing,red-banded and (2) seasonmales had their maximum breeding malesdid not pair significantlymore frequently performancea. with black-banded females than did other males (red maleshad 0/8 re-pairingswith black-band- Combi- ed females vs. 3/9 for males without red; Fish- nation 1985- 1986- 1987- 1988- included 1986 1987 1988 1989 er's exact test, P = 0.21). This suggeststhat the most attractive males do not pair up with the Year of banding b most attractive females. Green 11 5 9 11 Red 8 9 17 4 I found 15%of females(18/123) alsore-paired, Neither 13 9 16 3 but there was no significant difference in the proportion that re-paired between black-band- Year of maximum breeding performancec Green 9 4 7 17 ed females and those without black (4/42 black Red 8 2 9 15 vs. 14/77 without black; Fisher's exact test, P = Neither 9 6 7 19 0.19). Of 18 that re-paired three did so with

' If males bred in two or more breeding seasons,they were allocated malesthat had both red and green in the com- to that season in which most clutches were laid. bination, and of the remaining 15 there was no •' H•.: No significantdifference in proportionof malesallocated three significantbias towardsred males from chance types of combinationsover four study seasons(G = 11.24, P - 0.08). ' H,.: No significantdifference in proportionof maleswith threetypes expectation(8 red, 5 green and 3 neither red of combinations,and their seasonof maximum reproductiveperfor- nor green; goodness-of-fittest, G = 2.03, df = mance (G - 2.32, P = 0.89). 2, P = 0.36). manceof the two band categoriesfor number DISCUSSION and size of clutchesproduced, number of eggs laid, number of young that reachedindepen- Bodycondition and survivorship.--But for slight dence,and duration of the pairbond (Table 5); fading of bill color in females, evidence of re- however,contrary to expectation(Burley 1986b), productivecosts on body conditionis not com- the black-bandedfemales fledged significantly pelling in the Cloverleaexperiment. There were fewer young than did females with no black no significantchanges in massover the breed- (medians3 and 4.5 respectively;Wilcoxon two- ing interval for either sex or band-colortype; sample test, z = 1.97, P = 0.048). furthermore,birds continued to replace pri- Re-pairings.--Ifound 15% of males (18/123) mariesduring the breedingperiod, although at had more than one femalepartner during the a slower rate in females than males. Previous study, but there was no significantdifference investigationsat a neighboringcolony, Padgett, in the proportionsacross band-color categories where therewas no baitedwalk-in trap,showed (8/42 red-bandedmales re-paired, 3/36 light- that the rateof featherreplacement was signif- green-banded males, and 6/36 males with nei- icantly fasterduring the breedingseason than

TABLE5. "Lifetime"reproductive performance of femaleZebra Finches by leg-bandcolor (n in parentheses). Medians with interquartile rangesin parentheses.

Female bands included Black.'(42) No blackb (63) Test• Independentyoung 0 (0-1) 0 (0-3) 1.51 Fledglings 3 (0-5) 4.5 (1.5-8) 1.97' Eggs 6.5 (5-11) 6 (4-14) 0.45 Clutch size• 5 (4.0-5.5) 5 (4.3-5.5) 0.48 Number of clutches 1.5 (1-2) 2 (1-3) 0.86 Pair-bond duration 52 (25-95) 57 (25-105) 0.23 ' One metal band, one black band, and two other colors. •'One metal bandand three other colors,excluding black. • Wilcoxontwo-sample test (z; normal approximation with continuity correction of 0.50;SAS vet. 6.06 1990); *, P < 0.05;others not significant (P > 0.05). • Numberof eggslaid/number of nonpredatedclutches that reached incubation stage. 138 RICHARDZANN [Auk,Vol. 111 during the nonbreedingseason, which implies ment and for 15 months in the banded-female that reproductive stressneed not affect feather experiment; however, continuous breeding in replacement;however, during the peak of nest- the wild is never this long becauseof the in- ing activity, fewer females were in molt than tervention of unfavorable conditions. The num- males (Zann 1985). Despite the biparental na- ber of "equally good months for breeding" ture of broodcare reproductive effort is greater (EGM, a derivative of the Shannon-Wiener di- in females than males: females (mean mass 13 versity index; MacArthur 1964), which is an in- g) lay five eggs (each about 1 g) and are re- dex of the length of the breeding seasonin sponsible for all of the nocturnal incubation birds, can be calculated for the four, mostly and one-half the diurnal incubation (Zann and southern sites in Australia where Zebra Finch Rossetto 1991). Overall, the evidence indicates breeding (number of nestswith eggs)has been that under the breeding conditionsat the Clo- monitored each month for a year or more: (1) verlea colony:(1) bill colorand featherreplace- Griffith (35ø20'S, 149ø9'E), 8.6 EGM (Frith and ment are more sensitive indicators of stress than Tilt 1959); (2) York (31ø52'S, 116ø47'E),8.0 EGM mass;and (2) reproductivestress appears to have (Davies 1979); (3) Armidale (30ø30'S, 151ø40'E), only a slight effect on female condition and no 8.9 EGM (Kikkawa 1980); (4) Danaher (36ø09'S, detectableeffect on that of males.Consequent- 145ø26'E),7.6 EGM (this study).For mostspecies ly, there were no significantdifferences in sur- of birds the breeding seasonis longer at lower vivorship between the sexesover the course of latitudes (Wyndham 1986), but this is not so the study. with Zebra Finchesbecause breeding is inhib- It is feasible that the food ration at the walk- ited in the wet-dry tropicsof northwesternAus- in trap supplemented the diet to an extent that tralia (15ø42'S,128ø36'E) by too much or too little it blunted the costsof reproductionso that early monsoonrain, leaving only six months of the signs of reproductive stresswere not evident; year suitable for breeding (Immelmann 1963, however,previous studies on the effectof sup- 1965a,b). Therefore, throughout much of the plementedseed at the Padgettcolony showed distribution, there is a nonbreeding period of that it did not have a strongeffect on breeding at least three to four months every year that and, even without supplementation, seed re- limits the extent of continuous breeding; this sourcesare not limited at Cloverlea exceptdur- may prevent thoselevels of reproductivestress ing very early spring (Zann and Straw 1984). It reached in the laboratory. Furthermore, the is alsopossible that a nonbreedinginterval al- nonbreeding pausein the wild may allow some lowed birds at Cloverleato recoverfrom repro- recovery from reproductive stress that is not ductive stressbefore I could recapture them. possibleunder continuousbreeding regimes in Indeed, Burley et al. (1992) found that under a the laboratory. high-quality aviary diet, recently caughtZebra In harsher, more arid environments, Zebra Finchesat Alice Springs that were prevented Finchesmay be more susceptibleto reproduc- from breeding could significantly increasebill tive stress.After a two-year drought in 1986, color in just three weeks. They also found that Zebra Finchesat Alice Springs(a semi-aridzone) bill color of domesticatedmales, which grad- had bill colors (transformed Munsell scores)be- ually fades over a nesting cycle, can rebound fore breeding that were almostidentical to those rapidly between nesting cyclesimplying that at Cloverlea(X' = 21.8and 17.6 for AliceSprings factorsother than reproductiveeffort may also males and females, respectively [Burley et al. affect bill color. 1992] vs. 21.8 and 17.3 for males and females at In contrast to the situation at Cloverlea, where Cloverlea [Table 2]). However, the scores after there were no significant differencesin survi- the breeding interval were lower at Alice vorshipbetween color-band types, Burley (1985, Springs (19.59 and 14.67) than at Cloverlea (21.4 1986b,1988a) found that mortality ratesof do- and 16.5) for males and females, respectively. mesticatedZebra Fincheswere significantlyaf- Whereasthe decline in color was significantfor fectedby leg-bandcolor when subjectedto pro- both sexesat Alice Springs,only the femalesat longedbreeding episodes: red-banded males and Cloverlea showed significant decline. Thus, de- black-bandedfemales lived longer than light- spite similar bill colorsat the onset of breeding green-bandedmales and light-blue-bandedfe- and the fact that both colonies had ad libitum males.Birds were allowed to breedcontinuously supplies of commercial seed at the baited walk- for 22 monthsin Burley'sbanded-male experi- in traps, the birds at Alice Springs may have January1994] Band-colorEffects inWild Zebra Finches 139 been in poorer conditiondue to the drought neither a red nor light green in their combi- and less able to withstand reproductive stress nation.This is moststrikingly manifestedin the than birds at Cloverlea. Alternatively, they may numberof eggslaid, due principally to an extra have made a greater reproductive effort over clutch laid by matesof red-bandedmales, al- the breeding interval and, thus, have been sub- thoughthere is a suggestion(nonsignificant sta- jected to greater stress. tistically;P = 0.07) that thesefemales also lay Under optimal aviary conditions Zebra largerclutches. There was no significantband- Finches are renowned for prolific breeding; up color effect for number of fledglings, nor num- to 23 successivebroods have been raised by a ber of independentyoung, althoughin both single pair in a continuous"reproductive sea- instances median values were greater for pairs son" of three years (Serventy 1971). Conse- with red males. Unfortunately, nest mortality quently, aviculturistsare advised to remove was high (64% of all attemptsreached the in- nesting sites in order that excessivebreeding cubationstage and 41% of these producedat not "weaken the birds" (Immelmann 1965b). leastone fledgling; however only 32%of fledg- Data on continuous breeding throughout a sea- lings were recapturedafter 35 days, the age son by free-living pairs are difficult to collect when nutritional independenceis achieved)due since not all nests and pairs can be found and mainlyto predation,which reducedthe sample monitored. Nevertheless, females from 22 pairs size so that any small differencesin production at the Danahercolony that were monitoredfair- of fledglings and independent young across ly regularly throughout one breeding season band-colortypes were not statisticallydetect- fledgeda mean of 11.1 + 3.66 young (range8- able.The longer pair bond of maleswith a red 19) over a mean period of 4.0 + 1.46 months bandis probablyan outcomeof the extraclutch (range 2-6). In order to make the data compa- being laid by their mates,since I defined the rable to the captivesituation, any pairs whose start and end of the pair bond, in most instances, breeding attemptssuffered predation were ex- in terms of first and last breeding attempts. cluded and only pairs that producedat leasttwo In this retrospectiveanalysis of the effectsof clutcheswere included. Thus, females making band colors on reproductiveperformance of multiple breeding attemptswithout predation males, it is difficult to exclude artifacts due to produceda mean of 2.75 fledglingsper month impropersampling as explanations for the extra of the breeding season.By comparison,the fe- clutchlaid by matesof red-bandedmales. Band males in Burley's (1986b, c) banded-female ex- combinations were not allocated in a statisti- periment produceda maximumof 1.2 indepen- cally randomway, but in a blind or haphazard dent young per month of the much longer procedure.However, over the four study sea- "breeding season."Assuming that most fledg- sons there was no significant departure from lings in the laboratory reach independence,it random in the proportion of the three color suggeststhat wild Zebra Finchesmay achieve categoriesallocated to the subjectmales, nor in a higher reproductive successper month of the reproductivedata gatheredfrom them. If breeding activity than domesticated Zebra birds with red bands were more conspicuousin Finches,yet reduce reproductivestress with a the field, it is conceivable that nesting attempts shorter breeding season.Furthermore, wild Ze- by pairswhere a male was red-bandedwould bra Finchesmay be more resistantto reproduc- be easierto discoverand to identify. This could tive stress than domesticated ones because hu- lead to the situation where they would be ob- man intervention in the latter has caused served for longer intervals and so allow the pronouncedchanges in selectionpressures that detection of an extra clutch that might go un- affect reproduction(Sossinka 1970, 1982). The detectedin pairs with other color bands.This extent of reproductivestress in wild-caught Ze- explanationis unlikely,first because the red bill bra Finches under conditions of continuous makesall birds equally conspicuousto discover breeding should be investigatedto verify this in the first placeand, second, the red colorband possibility. was the most difficult to identify of all band Reproductiveperformance.--At the Danaher colorsbecause it faded quite rapidly and was colony, mates of males with one red band in often hard to distinguishedfrom orange;it also their color combination made a significantly providedthe leastcontrast with the reddish- greater reproductive effort than did mates of orange leg. males with a light-green band, or mates with It is also conceivable,but unlikely, that the 140 RICHARDZ.a•Ihl [Auk, Vol. 111

red band conferred an advantage to male Zebra in the number of eggs laid in the two groups Finches because it enhanced their aggressive (Wilcoxon two-sample test, z = 0.73, n = 12 and display. Red bands are known to affect the ag- 21; P = 0.46). This suggeststhat differential ac- gressivedisplay of Red-cockadedWoodpeckers cessto superior quality femalesprovided by red (Picoidesborealis; Hagan and Reed 1988)and Red- bands did not produce a significant increasein winged Blackbirds(Agelaius phoeniceus; Metz and the reproductive successbeyond that which Weatherhead 1991, 1993), both of which have could be explained by the differential-alloca- patches of red plumage. Zebra Finches are not tion hypothesis. territorial and did not compete for nesting sites Two important differencesin design exist be- or food, which were both abundantat my study tween Burley's studies (1981, 1986a, b, 1988a) site. Moreover, Ratcliffe and Boag(1987) found and my own: (1) only one member of each pair that leg-bandcolors did not affectthe ability of of domesticatedbirds had colored leg bands in domesticatedZebra Finches to competefor nest Burley's (1988a) study (males in banded-male sites and females. Thus, in the field situation it experiment and females in the banded-female is hard to see how a red band could confer an experiment), whereas both partners at my two advantagein male-male competition for limit- colonieswore coloredbands; (2) many wild birds ing resourcessuch that an extra clutch would were probably already paired and may have be produced through earlier breeding, or bred before banding, whereasthe domesticated through breeding in a more favorable location. birds were all unpaired and had not previously Differencesin survivorship and reproductive bred. Therefore, differential access to mates success ascribed to band colors in domesticated (Burley 1986b, 1988a) due to band color may Zebra Fincheshave been explained by two non- have been limited to some degree in the field mutually-exclusivehypotheses: (1) the differ- studies except in casesof re-pairing (15%). ential-accesshypothesis (Burley 1986b);and (2) Despite these differences, males with red the differential-allocation hypothesis (Burley bands in both studies averaged a greater num- 1988a).In the former, attractive band colorsper- ber of clutchesthan did maleswith light-green mit the bird to pair with a superior member of bands or males with bands of neutral attrac- the oppositesex so that the attractiveindividual tiveness,as predicted by the differential-allo- produces more offspring of a superior quality cation hypothesis(Burley 1986b:427).In addi- than do birds that do not get superior mates. tion, in both studies there were no significant With the exceptionof extrapaircopulations, this differences in mean number of clutches and re- mechanismshould operate only when the bird productive successfor light-green-bandedand is given the attractive band color before pair neutral-banded males. The hypothesispredicts formation. If given an attractiveband after pair that light-green-banded males would have less formation, the bird is stuck with the current parental investmentby their partnersbut make partner. This partner can then respondto the more investment themselves, thereby increas- sudden increase in attractivenessof the partner ing their own reproductivecosts, which sub- by increasingits allocation to the reproductive sequently reduce their life-span. The survivor- effort of the pair. Hence, if birds are given the ship data from the wild Zebra Finches did not color band before they reach the age of pairing, confirm this prediction. Red-banded males both hypothesescould operate, but if the bird should have had a greater re-pairing rate than is already paired when the band is acquired males with neutral colors as a consequence of then only the differential-accesshypothesis their greater attractivenessto females and the should operate. To evaluate this possibledif- fact that life-span of their mates should be ferenceI comparedthe number of eggslaid by shorter. This was not the case at Danaher but matesof red-banded males accordingto wheth- some red-banded males in Burley's (1986b:425) er the males were banded before the age of pair laboratorystudy becamesimultaneous polygy- formation or afterwards. Although some pairs nists. form and lay eggsbetween 60 to 70 days,many Presumably,in the caseof red-bandedmales do not lay until older so that in the analysis at Danaher, their females detect the sudden in- birds first banded at 90 days or earlier were creasein their partners' attractivenessand re- assumed to be unpaired, whereas older ones spond with increased reproductive effort by were assumed to have been paired at the time laying more eggs;however, this doesnot appear of banding. There was no significantdifference to be translated into more fledglings and in- January1994] Band-colorEffects in WildZebra Finches 141 dependent young, perhaps becausered-banded on the effectsof leg-band color on Zebra Finch males do not increase their parental expendi- behavior. The experimental study at Cloverlea ture in responseto that of their partner suffi- found no evidence for band effects on survi- cient to raise the young to fledging and inde- vorship or reproductive stress.The experimen- pendence. A larger sample size might detect tally weaker retrospectiveanalysis of band ef- significantdifferences. Apparently, red-banded fects on reproductive performanceat Danaher laboratory males perceive the change in their provided partial support for Burley'shypoth- attractivenessand gradually decreasetheir pa- esis,but only for red bandson males.There was rental expenditure over time, whereas light- no evidence that other band colorshad any ef- green-banded males increase theirs (Burley fect on behavior of malesor females,except for 1988a:622).The tendencyfor matesof red-band- black bands on females, which had an effect ed wild males to lay a larger clutch was not that went in the opposite direction to that pre- found in domesticatedbirds, leading Burley dicted by Burley. Finally, the significant red- (1986b, c, 1988a) to conclude that clutch size band effect on males did not alter their fitness cannotbe adjustedfacultatively. becausethey did not have a significantincrease DNA fingerprinting of parentsand broodsat in numbers of surviving offspring over males Danaher early in 1988 indicated that 10 of 25 banded with other colors. In sum, it is reason- broodshad one nestling from an egg laid by an able to conclude that color bands do not create infraspecific brood parasite (Birkhead et al. significant biasesin most aspectsof the behav- 1990). In one case the male nest owner, who ior of wild Zebra Finches, but in future studies had no red bands,was thought to be the father it would be wise to allocate color combinations and the parasite the mother. It is possible that in a statisticallyrandom way and to avoid where red-banded males in this study are attractive to possible the use of red bands on males. other femaleswho trade an extrapair copulation for the opportunityto "dump" their eggsin the ACKNOWLEDGMENTS males' nests. This is one possible explanation for larger clutches of red-banded males, but it I thank L. and M. Powney (Cloverlea)and B. and cannot explain why an extra clutch was laid. M. Danaher for generousaccess to their farmswhere Whereas the effect of red-banded males on the study sites were located. David Runciman and Bruce Male collected and entered most of the field reproduction correspondsreasonably well be- data. The M. A. Ingram Trust, La Trobe University tween field and laboratory studies,the situation and the Australian ResearchCouncil funded the pro- with banded females differed significantly. ject. Permits were provided by the Victorian Depart- Black-bandedfemales at Danaher had signifi- ment of Conservation and Environment and the Aus- cantly fewer fledglings than did those banded tralian Bird and Bat BandingScheme. Nancy Burley with neutral colors, but there were no signifi- trained us in the correct use of Munsell chips for cant differences in Burley's (1986b:442) labo- scoringcolors. Mike Clarke,Ian Thornton,Aldo Poiani, ratory study; however, she did find that light- David Runciman,and three anonymousreviewers blue-bandedfemales had only one-half asmany madevaluable comments on draftsof the manuscript. offspring as femalesbanded with black or neu- tral colors. In the laboratory the increased re- LITERATURE CITED productivesuccess of black-bandedfemales was ASHMOLE,N. P. 1962. The Black Noddy Anousten- due to their greater survivorship, presumably uirostris on Ascension Island. Ibis 103b:235-273. an outcome of lower reproductive costs in- BELETSKY,L. D., AND G. H. ORIANS. 1991. Red bands curred on their part arising from the compen- and Red-winged Blackbirds.Condor 91:993-995. sating increase in reproductive effort by their BIRKHFAD, T. g., T. BURKE, g. ZANN, F. M. HUNTER, partner; however, survivorship of females at ANDA. P. KRUPA. 1990. Extra-pair paternity and both Cloverlea and Danaher colonies was in- intraspecific brood parasitism in wild Zebra dependent of band color and, consequently, FinchesTaeniopygia gutrata, revealed by DNA fin- gerprinting. Behav.Ecol. Sociobiol.27:315-324. lowered reproductive successof black-banded BURLEY,N. 1981. Sex-ratio manipulation and selec- femalesis unlikely to be due to a reducedlife- tion for attractiveness. Science 211:721-722. span. BURLEY,N. 1985. Leg-bandcolor and mortality pat- Taken together, the resultsof the two studies terns of captive breeding populations of Zebra provide mixed, somewhat equivocal, support Finches. Auk 102:647-651. for Burley's (1981, 1985, 1986a,b, c, 1988a)ideas BURLEY,N. 1986a. Comparison of band color pref- 142 RICHARDZANN [Auk, Vol. 111

erencesof two speciesof estrildid finches.Anim. KIKKAWA,J. 1980. Seasonalityof nesting by Zebra Behav. 34:1732-1741. Finches at Armidale, N.S.W. Emu 80:13-20. BURLEY,N. 1986b. Sexual selection for aesthetic traits MACARTHUR, R.H. 1964. Environmental factors af- in specieswith biparentalcare. Am. Nat. 127:415- fecting speciesdiversity. Am. Nat. 98:387-397. 445. METZ, K. J., AND P. J. WEATHERHEAD.1991. Color BURLEY,N. 1986c. Sex-ratio manipulation in color bands function as secondarysexual traits in male banded populations of Zebra Finches. Evolution Red-winged Blackbirds.Behav. Ecol. Sociobiol. 40:1191-1206. 28:23-27. BURLEY,N. 1988a. The differential allocation hy- METZ, K. J., AND P. J. WEATHERHEAD.1993. An ex- pothesis:An experimentaltest. Am. Nat. 132:611- perimentaltest of the contrasting-colorhypoth- 628. esis of red-band effects in Red-winged Black- BURLEY,N. 1988b. Wild Zebra Finches have band- birds. Condor 95:395-400. colour preferences.Anim. Behav. 36:1235-1237. MILLER,A.H. 1961. Molt cyclesin Andean sparrows. BURLEY,N., G. KRANTZBERG,AND P. gADMAN. 1982. Condor 63:143-161. Influence of colour banding on the conspecific RATCLIFFE,L. M., AND P. T. BOAG. 1987. Effects of preferencesof Zebra Finches.Anim. Behav. 30: color bands on male competition and sexual at- 444-455. tractivenessin Zebra Finches (Poephilaguttata). BURLEY,N., AND C. COOPERSMITH. 1987. Bill colour Can. J. Zool. 65:333-338. preferencesof Zebra Finches.Ethology 76:133- SASINSTITUTE.1990. SAS user'sguide: Statistics,ver- 151. sion6.0. SASInstitute, Inc., Cary, North Carolina. BURLEY,N., R. A. ZANN, S. J. TIDEMANN, AND E. B. SAS INSTITUTE.1991. JMP ver. 2.0. Software for sta- MALE. 1989. Sex ratios of Zebra Finches. Emu tistical visualization. SAS Institute, Inc., Cary, 89:83-92. North Carolina. BURLEY,N., D. K. PRICE, AND R. A. ZANN. 1992. Bill SERVENTY,D. L. 1971. Biologyof desertbirds. Pages color, reproduction and condition effectsin wild 287-339 in Avian biology, vol. 1 (D. S. Farner, J. and domesticated Zebra Finches. Auk 109:13-23. R. King, and K. C. Parkes,Eds.). Academic Press, CRISTOL,D. A., C. S. CHIU, S. M. PECKHAM,AND J. F. New York. STOLL. 1992. Color bands do not affect domi- SOSSINKA,R. 1970. Domestikationserscheinungen nance statusin captive flocksof wintering Dark- beim Zebrafinken Taeniopygiaguttata castanotis. eyed Juncos.Condor 94:537-539. ZoologischeJahrbticher Abteilung fiir Systema- DAVIES,S. J.J.F. 1979. The breeding seasonsof birds tik •)kologieund Geographie der Tiere. 97:455- in south-western Australia. J. R. Soc. West Aust. 521. 62:53-64. SOSSINKA,R. 1982. Domestication in birds. Pages FRITH,I-I. J., AND R. A. TILT. 1959. Breeding of the 373-403 in Avian biology, vol. 6 (D. S. Farner, J. Zebra Finch in the Murrumbidgeeirrigation area. R. King, and K. C. Parkes,Eds.). Academic Press, Emu 59:289-295. New York. HAGAN, J. M., AND REED,J.M. 1988. Red color bands WEATHERHEAD,P. J., D. J. HOYSAK,K. J. METZ, AND C. reduce fledging successin Red-cockadedWood- G. ECKERT.1991. A retrospectiveanalysis of red- peckers.Auk 105:98-503. band effectson Red-winged Blackbirds.Condor 93:1013-1016. IMMELMANN,K. 1963. Tierische Jahresperiodikin 51ologischerSicht: ein Beltrag zum Zeitgeber- WYNDHAM,E. 1986. Length of birds' breeding sea- problem, unter besonder Berticksichtigungder sons. Am. Nat. 128:155-164. Brut- und Mauserzeiten australischer VSgel. ZANN, R. 1985. Slow continuouswing-moult of Ze- ZoologischeJahrbticher Abteilung fur Systema- bra FinchesPoephila guttata from southeastAus- tik •kologie und Geographieder Tiere91:91- tralia. Ibis 127:184-196. 200. ZANN, g., AND M. ROSSETTO.1991. Zebra Finch in- IMMELMANN,K. 1965a. Versuch einer 5kologischen cubation:Brood patch, egg temperature and ther- Verbreitungsanalysebeim australischenZebra- mal propertiesof the nest. Emu 91:107-120. finken, Taeniopygiaguttata castanotis(Gould). J. ZANN, R., AND B. STRAW.1984. Feeding ecology and Ornithol. 106:415-430. breedingof ZebraFinches in farmlandin north- ern Victoria. Aust. Wildl. Res. 11:533-552. IMMELMANN, K. 1965b. Australian finches in bush and aviary. Angus and Robertson,Sydney.