Second Broods in Wood Ducks

Abstract

Of 1,626 nesting attempts by wood ducks (Aix sponsa) in southeastern Missouri, 35 were 2nd clutches that were laid in the same season after an initial nest was successful. Most 2nd nests were initiated between 15 and 30 May and were an average of 876 m away from 1st nests. Clutch sizes were different between 1st and 2nd clutches, but hatching success was not. Most females known to raise 2nd broods were 2 years of age or older. Females with 2nd nests weighed less at initiation of incubation and lost less weight per day than during the 1st nesting. J. WILDL. MANAGE. 47(2):320-326 Wild anatids are not normally doublebrooded (Weller 1964:60), but some wood ducks are known to have more than 1 successful nest in a season. Thirty-nine cases of 2nd broods in box-nesting wood ducks have been reported in the literature (Table 1). This paper reports 2nd broods of wood ducks in southeastern Missouri. We present information on frequency of occurrence, distance moved, interval between the 2 nesting attempts, and the ages and weights of females that produced 2nd broods. We also examined the potential impact of 2nd broods on production of wood ducks. All records are from females nesting in boxes in southeastern Missouri within the 11,175-ha Mingo Swamp on Mingo National Wildlife Refuge (NWR) and Duck Creek Wildlife Management Area (WMA). This lowland hardwood wetland is the largest remnant of wood duck breeding habitat in Missouri (Korte and Fredrickson 1977, Fredrickson 1980). We are indebted to many colleagues for assistance and encouragement throughout the study. F. E. Hester, D. S. Gilmer, and T. S. Baskett reviewed the manuscript. G. W. Hartman, R. L. Clawson, C. E. Korschgen, R. E. Dobbins, N. R. Holler, M. J. Huebschen, and J. P. Rogers assisted with box checks. J. L. Boyles and B. T. Crawford of the Missouri Department of Conservation and J. E. Toll of the U.S. Fish and Wildlife Service made equipment and supplies available for our use.