608 General Notes [Auk, Vol. 94 KENDEIGH, S.C. 1952. Parental care and its evolution in birds. 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 Duck.--Although the literature of the Mandarin Duck (Aix galericulata)contains general naturalistic accounts (Savage 1952), little hasbeen publishedon its biology and early development.Because of its widespreadaesthetic appeal, this species 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 ducks 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 bird 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 thickness of 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 Mallards (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 plumage,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, preening, 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