608 General Notes [Auk, Vol. 94

KENDEIGH, S.C. 1952. Parental care and its evolution in . Illinois Biol. Monogr. 22: 1-356. SCHANTZ,W.E. 1939. A detailed study of a family of robins. Wilson Bull. 51: 157-169. YOUNG, H. 1955. Breeding behavior and nestingof the Eastern Robin. Amer. Midl. Naturalist 53: 329-352.

HERVEYBRACKBILL, 2620 Poplar Drive, Baltimore, Maryland 21207. Accepted1 Jul. 1976.

Morphological and behavioral development of the Mandarin .--Although the literature of the Mandarin Duck ( galericulata)contains general naturalistic accounts (Savage 1952), little hasbeen publishedon its biology and early development.Because of its widespreadaesthetic appeal, this occursin many private breedingcollections and zoos.This study comparedegg morphologyfrom known- age femalesand determinedanatomical and behavioral growth rates of the ducklings(Bruggers 1974). The studywas conductedat the 10-haestate of Mr. and Mrs. J. J. Schedel,Elmore, Ottawa Co., Ohio. Adult had one wing pinioned and were either maintained in large outdoor lake-sidepens or were free-rangingon two 0.6 and 1.0 ha interconnectedlakes. Nest boxeswere in the penssurrounding the lakes. Nests were checkedevery other day during the laying period while adults were absent.All eggswere marked, measuredwith calipers,and weighedon a torsionbalance at days 1 (freshweight), 15, and at pipping. The shell membrane was removedfollowing hatching and the shell thicknessmeasured with an Ames ThicknessMeasure modified for curved surfaces.An averagethickness for each egg was calculated from five readings taken around its center. Body weight, culmenlength and width, tarsusand middletoe lengths,and featherdevelopment of 5 malesand 8 femaleswere recorded at hatchingand at one-weekintervals during the summer.Measurements were made with vernier calipers,duplicating the methodsof Northern Prairie Wildlife ResearchCenter (Greenwood 1974). The 13 ducklingswere hatchedunder bantam henswithin a 2-weekperiod, individuallymarked, then reared successivelyin brooders,indoor pens with ponds,and lake-sidepens. They were given a commercial starter diet. Mandarin eggsare glossyand buff-white. The averagelength and the averagemaximum width of 106 eggsfrom 11 clutcheswas 52.86 x 38.64 ram, smallerthan the 56 x 39 mm for eggslaid by Mandarins in Japan (Nakata 1965), but slightly larger than the 48.8 x 36.3 mm of 18 Mandarin eggsfrom England (Savage1952). Width was lessvariable than length, a conditionalso noted by Preston(1958) for the eggsof many species. Freshegg weights averaged 43.72 g, similarto the 43-g averageof 68 eggsprovided by J. Kear in England (pets. comm.). Weights and lengthsof eggslaid by second-yearor older birds (46.26 g and 53.74 ram) were significantlygreater (P < 0.05) than of thoselaid by yearlingfemales (42.68 g and 55.52 ram), a phenome- non reportedin many species(Romanoff and Romanoff 1949,Preston 1958). Egg weightdecreased 10.5 % (43.75 to 39.1 g) during development,which Romanoff (1967) ascribedto water evaporation. The shell thicknessof 60 eggs(11 clutches)averaged 0.259 mm (range: 0.191-0.329 ram). This variation resulted from significantdifferences between clutchesand the inclusionof shellsfrom infertile eggs. Ducklingsweighed 20--30 g 12-36 hoursafter hatching(also recorded by Smart 1965and J. Kear, pets. comm.), with males(29 g) heavier than females(25 g) (Fig. 1). Similar sexualdimorphism was reported (Princeet al. 1970)for (Anasplatyrhynchos). Both sexesdoubled their hatchingweight in 1 week and were 13 times heavier after 5 weeks. Males averaged 100 g heavier than femalesat 6 weeks. Adult weight was attained after the first prealternatemolt in October, a pattern similar to Wood Ducks (Aix sponsa)(Lee, pets. comm.). The growthrate slowedduring the physiologicallystressful fledging period, body weight increasing only 8% (males)to 11% (females)during that time. Female GreenlandMallards (A. p. conboschas)gained only 55 g between the 6th and 8th geeeks(Greenwood 1974), and Weller (1957) and Kear (1970) observedactual decreasesin growth curvesof Redhead(Aythya americana) and Tufted Duck (Aythyafuligula). Rapid tarsusdevelopment, characteristic of pochards(Aythya) and presumablyan adaptationfor aquatic birds(Kear 1970),was completeby 6 weeks.This rapid growth in Mandarins(and probablyWood Ducks) alsomay be an adaptationto terrestriallocomotion. The ducklingsspent considerably more time walking and picking at insectsthan swimming, a phenomenonalso noted by Savage(1952) for wild Mandarin broods.Both he and Stewart(1958) observed movements of wild, newly-hatchedduckling broods up to 5.6 km from the nest to reach water. Newly-hatched Mandarin Ducks are brown dorsally and buff-yellow ventrally, with two light dorsal spots. The bills of both sexeshave a conspicuousorange tip, an episematic pattern by which parents July 1977] GeneralNotes 609 ---E--:MALES(N=5)• .-'//'"! •]•:FEMALES(N=8, '500

,'•- }/T" bodyweight '400 '-'

300 -r

,'•/J tarsuswdt -2oo 5O ,.,,• •/- J .... ,-:••,•,...... //I 8½ -lOO 4O • •/ ,,•.,•.•½ •,• tarsusIng E '-' 30 •.'• .- --.'•o l-•8•8•-•8: culmen.... •/---Ing ' O 20 z

' 10 s-/.--=•s•'• cuI men wdt

i ') 12,2'1 2'8 3'5 4'2 •9 5'66'3 7'0 7'7 7,/ 13o , AGE IN DAYS Fig. 1. Growthof Mandarinducklings at 1-weekintervals from hatching for 10weeks and again on 28 October 1973. Mean (_+ SD for body weight) indicated.

recognizetheir ducklings (Nakata 1965). The only evidence ofsexual dimorphism was the reddening ofmale billsat 28days (usually not a reliableindicator for another 1 or2 weeks)and change in thefemale's voice fromthe duckling contact call to the plaintive, more nasal "ack" at 6 weeks.The male's voice did not change to the whistle-like"pfrruib" until the 7th and 8th week. Thepostnatal molt was noticed first at 2 weeksof age.Juvenal feather groups generally appeared simultaneotlsly(Fig. 2). Scapular,tail, andbelly feathers were the first to appear,with coverts and secondariesbreaking the skin a weeklater. Primaries broke the skin at 3 and4 weeksin females and males, respectively,with all 10complete inboth sexes by 10 weeks. Natal down in the lumbar region and under the wings was lost between 8 and 11 weeks. Mandarinducklings apparently do not have a basicI ,molting from the juvenal directly to the alternateplumage. Green feathers begin to appear on the head and mane of the males and black stripes on thechest at 10-12weeks. The rectrices were replaced but not the remiges. The prealternate I molt was completedin all birds by the end of October. Birdsof both sexes flew at 7 weeks,with the first to seventh primaries cleared at thisdate. This was 1 week laterthan reported by Scottand Boyd (1957), but 1-3 weeksearlier than given for Mandarinand Wood Ducksby Savage (1952). This fledging period is similar to that of the Gadwall (Anas strepera) (Oring 1968) andother dabbling ducks (Anas spp.) (Weller 1957). Heinroth (1928) suggested that the shortened fledging 610 General Notes [Auk, Vol. 94 BILL

VOICE

PRIMARIES

SECONDARIES

SCAPULARS

BR EAST and STOMACH

HEAD

• 1•, 2•12'8 35 42 49 56 63 70 7784 AGE IN DAYS Fig. 2. Feather developmentand maturationalchanges in 5 male (brokenlines) and 8 female(solid lines) Mandarin ducklingsobserved at 1-weekintervals from time of hatching.Beginning and end of linesindicate first appearanceand full emergence,respectively, of particular feathers or characteristicsin each bird. No change occursin female bill color.

period of the less-aquaticdabblers (relative to the divers) is related to their vulnerability to predators and pressureto shorten the period of relative helplessness. The ability of day-old perchingducks to climb from a nestcavity and jump to the groundfrom as high as 15 m in responseto the call of the female is well-known (Gottlieb 1968, Johnsgard and Kear 1968). Mandarins sometimesclimb as much as 2 m inside a tree cavity from the nest to the entrance(Savage 1952). Day-old Mandarins were able to escapefrom a bushelbasket in two jumps of 15-20 cm by digginga long (4 mm average),sharp, middle claw into the wood, hanginga few seconds,then springingand grabbingthe top with the claw of the other foot. Meade-Waldo (1912) noted 2-day-old Mandarin ducklings leaping 45 cm from the water to a branch. The anatomicalfeatures, primarily thigh and leg musclesize related to this ability in perching ducks, have been discussedby Rylander and Bolen (1970). In comparison,Pengelly and Kear (1970) noted that Blue Ducks (Mymenolaimus malacorphynchus),nonperching ducks that inhabit fast-movingmountain streams,climb usingtheir chinsand couldjump 15 cm after only 6 days. Despite 2 weeksdifference in age, the Mandarin ducklingsfrequently nibbled at eachother's necks and headsand, at least until releaseto the outdoor pens at 6 weeks, slept touching each other. The rate and sequenceof appearancefor comfortmovements (shaking, stretching, , bathing, and other suchmovements) was like that observedfor Mallards (McKinney 1965) and Blue Ducks (Pengellyand Kear 1970). Most such movementsappeared in the first 2 days (Table 1). Newly hatchedducklings performed the samemovements as adults. Brief nibbling and preeningsessions July 1977] General Notes 611

TABLE 1 AGE AT WHICH COMFORT MOVEMENTS FIRST APPEARED IN FIVE MANDARIN DUCKS •

Age (days) Comfort movements Nibbling movements--belly,neck, vent, wings, and occasionallyin vicinity of oil gland Head-shake,body-shake, wing-flap, tail-wag, jaw-stretch,head-scratch, leg-and- foot peck Swim-shake Both-wing-stretchand wing-shuffle Oil preen with head-rollon back and side (oneduckling) Dashing-and-diving(two ducklings) All nibble at oil gland while swimming(first time observed) Dashing-and-diving(all ducklings),high intensitybathing (pecking at sides,head, neck, and oil gland while head-dipping) Unlessotherwise stated, the day indicatesthe timemovements were seen for all ducklings.

(to belly, neck,and wings)were frequentduring the first 3 days.As with Mallards(McKinney 1965), movementswere made in the directionof the preengland during the first 2 days;but fully-developedoiling sessions,with associatedhead rolls, were not seen until the4th day. Dashing-and-diving,a rather complex motor activity, occurredin two Mandarin ducklingsat 6 da.vsand the othersat 8 da.vs.This was considerablyearlier than the 13-14 days reportedfor Mallards. As the birdsutilized were from private breeding collections and inbred to an uncertainextent, they may not be whollyrepresentative of this Asianwildfowl, but the data obtainedwere similar to thoseavailable from other investigators. We are most thankful to Mr. and Mrs. J. J. Schedelfor allowingaccess to their estateand waterfowl collectionand to theSchedel Foundation for fundingmany of theproject activities. We alsothank J. Kear for providingunpublished data on eggweights and for readingthe manuscript,and C. Daneand R. J. Greenwoodof NorthernPrairie Wildlife Research Center, Jamestown, North Dakota, for initial discussions leadingto the formulationof studymethodology.

LITERATURE CITED

BRUGGERS,R. L. 1974. Nestingbiology, social patterns and displaysof the Mandarin Duck, Aix galericulata.Unpublished Ph.D. dissertation.Bowling Green, Ohio, BowlingGreen State Univ. GOTTLIEB,G. 1968. Speciesrecognition in ground-nestingand hole-nestingducklings. Ecology 49: 87-95. GREENWOOD,R.J. 1974. Reproductiveaspects, growth, and developmentof GreenlandMallards. Condor 76: 223-225. HEINROTH,O., ANDm. HEINROTH. 1928. Die ViSgelMitteleuropas. , H. Bermilhler. JOHNSCARD,P. A., ANDJ. KEAR. 1968. A review of parentalcarrying of youngby waterfowl.Living Bird 7: 89-102. KEAR,J. 1970. Studieson the developmentof youngTufted Duck. Wildfowl 21: 123-132. McKINNE¾, D. F. 1965. The comfort movements of . Behaviour 25: 120-220. MEADE-WALDO,E. G.B. 1912. Mandarin Ducksat liberty. Avicult. Mag. 3: 122. NAKATA,Y. 1965. Mandarin Ducks. Modern Game Breeding1: 29-31. ORING,L.W. 1968. Growth, molts,and plumagesof the Gadwall. Auk 85: 355-380. PENGELL¾,W. J., ANDJ. KEAR. 1970. The handrearing of youngBlue Ducks. Wildfowl 21:115-121. PRESTON,F.W. 1958. Variationof eggsize with the age of the parent.Auk 75:476-477. PRINCE,H. H., P. B. SIEGEL,AND G. W. CORNWELL.1970. Inheritanceof eggproduction and juvenile growth in Mallards. Auk 87: 342-352. ROMANOFF,A.L. 1967. Biochemistryof the arian embryo. New York, John Wiley and Sons. ROMANOFF,A. L., ANDA. J. ROMANOFF. 1949. The avian egg. New York, JohnWiley and Sons. RYLANDER,M. K., ANDm. G. BOLEN. 1970. Ecologicaland anatomical adaptations of NorthAmerican tree ducks. Auk 87: 72-90. 612 GeneralNotes [Auk, Vol. 94

SAVAGE,C. 1952. The Mandarin Duck. London, Adam and Charles Black. SCOTT,P., AND H. BOYD. 1957. Wildfowl of the British Isles. London, Country Life. SMART,G. 1965. Body weightsof newly hatchedAnatidae. Auk 82: 645-648. STEWART,P.A. 1958. Local movementsof wood ducks(Aix sponsa).Auk 75: 157-168. WELLER,M.W. 1957. Growth, weights,and plumagesof the Redhead,Aythya americana.Wilson Bull. 69: 5-38.

RICHARDL. BRUGGERSAND WILLIAM g. JACKSON;Environmental Studies Center, Bowling Green State University, Bowling Green, Ohio 43403. Present addressof senior author.' UNDP/SF Regional Project, Box 1716, Dakar, Senegal. Accepted 17 Jan. 77. (This paper was subsidizedby the Schedel Foundation.)

Willow Ptarmigan remove broken eggs from the nest.--In the courseof studiesof the breeding behavior of Ptarmigan (Lagopuslagopus lagopus) in northern Norway, we have now and again found singleptarmigan eggs lying near occupiednests. On Karls0y Island, near TromsO,an infertile egg with a holein it was foundsome 80 cm from a nestcontaining newly-hatched chicks and severalapparently infertileeggs. The holemight have been made by a bird'sbill, and we assumedthat the eggwas removed by the hen. Jenkinset al. (1963)mention similar observations on Red Grouse0L. I. scoticus).During a studyof eggand chick careby Willow Ptarmigan(Allen et al., ms.) at the Universityof Troms•'sWildlife Station, crackedor broken eggshave occasionallybeen found on the floor of the observationrooms, beyond the nest scrape where a clutch was being assembledor incubated. Such eggs had thin, rough-surfacedshells, probablythe result of dietary calciumdeficiency (Roland et al. 1974). The contentsof broken eggswere apparentlysometimes eaten by the birds, which were certainlythe only occupantsof theserooms. Detailed observationswere made on a ptarmiganhen that beganto lay on a scrapein someturfs placedon the observationroom floor. Her first egg was rough-surfaced,and by the time she laid five more, it lay crackedabout half meter from the nest. We replacedit in the nest and 3 days later found it smashedon the concretefloor, some3 m from the nest. The next day the egg was completelyeaten by one of the birds; no trace of the shellwas found. The followingday we markedtwo infertile eggsfrom anotherhen and added themto thosein the nest,deliberately breaking one in the process.Three dayslater botheggs still lay with the clutch, which was covered with leaves and grass, although by now the broken egg was crushed. The followingday it lay about a meter from the nest, almostempty; the hen subsequentlyincubated the other marked egg. The hen of another pair incubateda clutch of only 3 eggs,one of which we found broken and entrusted with driedyolk, about2 m fromthe neston the 15thday of incubation.We replacedit in the nestwhich we watched by closed-circuitTV. After a few minutes the hen returned to the nest and resumed incubation. Twice in the next 2 hoursshe rose and turned the eggsas usual, but shepecked at them, apparentlytasting and swallowingsomething, before settling again. The third time sherose she again pecked at the eggs,at first gently but then more violently. Within a few secondsshe had spearedthe broken egg on her upper mandible and carried it out of the nest, droppingit about a meter away. We removedthis egg, which containedonly fluid and appearedto be infertile. We then broke an eggcontaining a dead, almostfull-grown embryo, and placedit in the nest. The hen incubatedthis with her two remainingeggs, flattening it in the process,until we removed it for hygiene'ssake a week later. Meanwhile one of her own eggsdeveloped a longitudinalcrack, probablyfrom beingincubated directly on the concretefloor, but the shellmembranes did not ruptureand the eggdid notleak. The hencontinued incubating until we removedher fromthe room 8 dayslater, well after the remainingeggs should have hatched. This seriesof chanceobservations and opportunisticexperiments can only partly explainhow the hen recognizesand removesnonviable eggs. We suggesttentatively that the hen removesonly broken,leaking eggs,recognizing the taste,smell, or textureof the dried matter stickingto the shell, as sheturns them. Since suchmatter is easilytransferred to othereggs, she may testthe integrity of individual egg-shellsby peckingat them, as we saw one hen do. The only hen we saw actuallyremoving an egg, did soby "spearing"it, but otherswe have seenmay have been pushedout of the nest with the bill, or simply kicked, as they were not holed. One captivehen was onceseen catching up an eggbetween the undersideof her bill and her neck, and moving it thus (Myhre, pets. comm.). Broken eggsare non-viable, and there is good reasonfor the hen to clear them out of the nest;they are unnecessaryburdens on her capacityto transfer heat to the clutch, and are possiblesources of infection.