pi)' NESTING BIOLOGY. SOCIAL PATTERNS AND DISPLAYS OF THE MANDARIN DUCK, A_IX GALERICULATA Richard L. Bruggers A Dissertation Submitted to the Graduate School of Bowling Green State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY December 1974 ' __ U J 591913 W A'W .'X55’ ABSTRACT A study of pinioned, free-ranging Mandarin ducks (Aix galericulata) was conducted from 1971-1974 at a 25-acre estate. The purposes 'were to 1) document breeding biology and behaviors, nesting phenology, and time budgets; 2) describe displays associated with copulatory behavior, pair-formation and maintenance, and social encounters; and 3) determine the female's role in male social display and pair formation. The intensive observations (in excess of 400 h) included several full-day and all-night periods. Display patterns were recorded (partially with movies) arid analyzed. The female's role in social display was examined through a series of male and female introductions into yearling and adult male "display parties." Mandarins formed strong seasonal pair bonds, which re-formed in successive years if both individuals lived. Clutches averaged 9.5 eggs and were begun by yearling females earlier and with less fertility (78%) than adult females (90%). Incubation averaged 28-30 days. Duckling development was rapid and sexual dimorphism evident. 9 Adults and yearlings of both sexes could be separated on the basis of primary feather length; females, on secondary feather pigmentation. Mandarin daily activity patterns consisted of repetitious feeding, preening, and loafing, but the duration and patterns of each activity varied with the social periods. Diurnal activity rhythms were obvious only during the summer and fall. Females incubated 80% of the daytime and did not leave the nest at night. Males threatened conspecifics and waited for their females from loafing spots throughout incubation and attended their mates during their two daily inattentive periods. Mandarins (unless incubating) generally spent the night on the water, swim-feeding until 2200, then floating concealed near shore but alert. Some fed until 0200. Copulations were initiated by the female. Adult sequences were more stereotyped than yearling sequences; the latter's were longer in duration (as was mounting) and contained more displays. Social display occurred only in the female's presence, much of the display being directed to her. Females, through their movements, postures, and vocalizations, both initiated and intensified male social display. Females indicated their preference for a particular male by Inciting him against other birds. The season was important in both the method and length of time necessary for pairs to form. Fall or winter pairing took several weeks and involved social display, directed courtship, and changing partners. Late spring pairing(in the absence of social display) resulted from direct attempts by either sex, and bonds formed in a week. m ACKNOWLEDGEMENTS I am indebted to Mr. and Mrs. J.J. Schedel for allowing me access to their estate and waterfowl collection and to the Schedel Foundation for funding many of the project activities. The opportunity to observe and participate in the propagation of so many exotic waterfowl species in such a beautiful setting was unique. Appreciation is likewise extended to Slim Bouldin, the estate caretaker, and to those individuals indicated in Appendix I. In particular, I am grateful to Dr. Charles Dane for his hospitality during my visit to Northern Prairie Wildlife Research Center, and his suggestions regarding ageing techniques; Mr. Ray Greenwood for providing nasal saddles; Mr. Charles Webster for providing some ducks as well as allowing me to visit his estate on several occasions and observe his waterfowl collection; and Dr. Janet Kear, for her helpful comments during the study. I also am grateful to Dr. Frank McKinney for letting me view his waterfowl behavior films and for discussions which helped in the formulation of study procedures and interpretations. Thanks are extended to the members of my committee, Drs. T.R. Fisher, Stephen Vessey, William Baxter, Reginald Noble, and John Paul Scott for their evaluation of the manuscript, and my adviser, Dr. William B. Jackson, for his guidance and encouragement during the study and throughout my graduate career. Finally, I must thank you, Jackie, for your help in collecting some of the data, and for preparing and illustrating parts of the manuscript. You were most patient and understanding (usually)I a iv TABLE OF CONTENTS Page INTRODUCTION AND PURPOSE .... ................................................ 1 METHODS. ........................................ 15 RESULTS AND DISCUSSION.....................................................................29 Reproductive and developmental biology............................. 29 Copulation frequency and success.................................29 Nesting and incubation.....................................................35 Egg morphology.....................................................................54 Duckling development................... 56 Ageing yearlings and adults.............................................66 Time budgets....................................... 73 Spacing behavior.................................................................73 Population time budgets.....................................................77 Individual time budgets.....................................................83 Displays........................................ .92 Descriptions.........................................................................92 Social displays...................................................................112 Copulation sequences ....................... 124 Display motivations...........................................................145 SUMMARY.................................................................................................. 148 LITERATURE CITED ............................................................................ 166 APPENDIX ........................................................... 172 V LIST OF TABLES Page Table 1 Number of individuals (pinioned) of exotic waterfowl species present on Schedel Estate, Elmore, Ohio during March, 1970-1974 ............................................................................17 Table II Predators trapped at Schedel Estate 1971- 1973 and predation between 20 April-30 May, 1972....................................................................................... 18 Table III Chronology of male and female introductions into adult (experienced) and yearling (inexperienced) 3-male courting parties, winter, 1973........................................................................27 Table IV Proportion of Mandarin copulations during the pre-layino, laying, and renesting periods in 1971 and 1973 ....................................................................31 Table V Outcome of 47 copulatory sequences of yearling and adult Mandarins recorded during 1971 and 1973 ....................................................................34 Table VI Frequency of nest box inspection by 8 Mandarin pairs during pre-laying and laying periods in 1971 and 1973. ............................................ 36 Table VII Nest boxes used by Mandarins 1971-1974.................... 38 Table VIII Comparison of the number of eggs and fertility in first and second clutches of Mandarin females (allowed to complete the clutch uninterrupted), whose initial clutch was destroyed by a predator or removed for incubation............................................................................43 Table IX Nesting biology of seven Mandarin females observed during 1973 and 1974 .................................... 46 Table X Temperatures in middle of nests during incubation and at intervals during rest periods............................................................................... 49 Table XI Mandarin duck egg morphology under various conditions........................................................................... 55 vi Page Table XII Age at which comfort movements first appeared in five Mandarin ducklings, hatched 17 June 1973 and kept in captivity........................................................................64 Table XIII Average number of comfort movements/ duckling/ten minutes at four, seven, eight, and nine days of age - June 1973 ................................................................................65 Table XIV Primary feather lengths of male and female Mandarin ducks................................................68 Table XV No. and % yearling and adult Mandarin females with "complete" or "incomplete" white markings on the distal ends of the secondary feathers............................................ 71 Table XVI Mandarin feeding patterns, based on the proportion of birds engaged in each type of feeding at 1/2 h intervals during 1973. ........................ ....................................... 84 Table XVII Percent time spent in various activities during two morning and three evening inattentive periods by a Mandarin pair during the incubation period, spring 1973 ................................................................................89 Table XVIII Description and use of female vocalizations........................................................... 10 3 Table XIX Descriptions and use of male vocalizations . 104 Table XX Frequency of displays and agonistic encounters (pecks,