Leigh H. Fredrickson

Dump Nesting in a Missouri Wood Duck Population

Dump nesting (2 or more hens laying eggs in 1 nest box) was a common phenomenon in a population of wood ducks (Aix sponsa) in southeastern Missouri. Nesting attempts increased from 47 in 1966 to 181 in 1974. Percentage of young from dump nests increased from 22 in 1966 to 86 in 1974. The additional production from dump nesting represented 23% of the young produced. Survival rates for young from normal and dump nests were similar. Dump nesting was not age related. Dump nesting females visited nest boxes before laying and some dumped eggs before nesting normally. Females tended to tolerate intrusion by other females during laying but repulsed intruders during incubation. Parasitic and host females derived maximum benefit from the limited nest sites available because of their behavioral characteristics. J. WILDL. MANAGE. 43(2):347-355 This paper reports on dump nesting in wood ducks from 1966 to 1974 on the 2,443ha Duck Creek Wildlife Management Area in southeastern Missouri. Behavioral aspects associated with the dump nesting phenomenon and the effects on productivity were emphasized. The primary study site was a man-made reservoir of 718 ha where from 71 to 118 nest boxes were available during the study. Boxes were made of wood or galvanized metal and were mounted over water on trees or poles. Twenty boxes were placed around a permanent blind to facilitate detailed behavioral studies. J. P. Rogers and N. R. Holler collected data in 1966 and 1967, respectively. G. W. Hartman and R. L. Clawson conducted intensive observations during the breeding seasons of 1970-71 and 197374, respectively. L. H. Fredrickson maintained continuity in the program during the remaining years. We thank the Missouri Department of Conservation for providing equipment used in the study, and many individuals of the Gaylord Memorial Laboratory for assistance in fieldwork. D. S. Gilmer reviewed the manuscript and offered many helpful suggestions.

Late winter survival of female mallards in Arkansas

Determining factors that limit winter survival of waterfowl is necessary to develop effective management plans. We radiomarked immature and adult female mallards (Anas platyrhynchos) after the 1988 and 1989 hunting seasons in eastcentral Arkansas to test whether natural mortality sources and habitat conditions during late winter limit seasonal survival. We used data from 92 females to calculate survival estimates. We observed no mortalities during 2,510 exposure days, despite differences in habitat conditions between years. We used the binomial distribution to calculate daily and 30-day survival estimates plus 95% confidence intervals of 0.9988 ≤ 0.9997 ≤ 1.00 and 0.9648 ≤ 0.9925 ≤ 1.00, respectively

Dynamics of the platyhelminth fauna of wood ducks in relation to food habits and reproductive state.

The dynamics of the intestinal helminth fauna of wood ducks (Aix sponsa) and the relationship between changes in food habits and helminth populations during the birds reproductive cycle were studied in southeast Missouri. A total of 11 species of helminths, comprised of four species of trematodes and seven species of cestodes, were recovered from the digestive tracts of 155 wood ducks. All species except one were found in both sexes. Significant differences were found in parasite numbers by season (spring vs. fall), sex, and stage of the reproductive cycle. Helminth infection in both sexes was higher in the spring than during fall courtship; however, the magnitude of the seasonal difference was considerably greater in females. Females contained significantly more helminths than males during spring, but no sex-related differences were detected in the fall. Seasonal changes and sex-related differences in parasite numbers corresponded closely with the consumption of invertebrates that serve as intermediate hosts. The average number of parasites in females was similar during fall courtship and pre-egg-laying, suggesting that little or no new infection occurred during winter. The most intensive infections were found in laying females and were attributed to hyperphagia and increased invertebrate consumption during egg production. A large decrease in the parasite numbers in females between incubation and fall courtship indicated that most of the helminths acquired by laying females were lost during summer; therefore, the long-term effects of the increased infection are probably negligible.

Evaluating cultivation near duck blinds to reduce lead poisoning hazard.

After 10 years of hunting on a state waterfowl area in Missouri, lead shot in 215 soil samples taken 5.1 cm deep in front of 2 fixed blinds were more than 4 times as numerous in uncultivated as in cultivated soils. In 220 soil samples taken 9 years later in front of 5 blinds, percentage of shot content of 5 cm soil strata sampled to a depth of 25 cm differed significantly in samples from recently cultivated areas vs. samples from less recently and less frequently cultivated check areas. The top 5 cm stratum contained 66.5 percent of the shot in check areas but only 45.0 percent in recently cultivated areas. Where water control and soil conditions permit, cultivation near hunting blinds can lessen the availability of residual lead shot to waterfowl by burying it more deeply in the soil.

Food Use by Migratory Female Mallards in Northwest Missouri

We studied foods of migratory female mallards (Anas platyrhynchos) relative to habitat and molt during fall 1984 and 1985 in northwest Missouri. Females consumed primarily plant foods in moist-soil, arrowhead (Sagittaria latifolia), and mixed habitats (mixtures of moist-soil and arrowhead plants), but the importance of individual foods varied among habitats. Seeds of wild millet (Echinochloa spp.) and nodding smartweed (Polygonum lapathifolium) accounted for 85% of the mallard diet in moist-soil habitat, whereas seeds and tubers of arrowhead comprised >40% of the diet in arrowhead habitats. These foods and rice-cutgrass (Leersia oryzoides) seeds were important in mixed habitats. Invertebrates comprised 1.6, 6.3, and 17.1% of the diet by mass for females from moist-soil, mixed and arrowhead habitats, respectively. Invertebrate consumption was not correlated with intensity of molt and did not vary with molt completion. Diets of female mallards collected at roosts during fall and spring consisted of primarily agricultural foods

Second Broods in Wood Ducks

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.

MEASUREMENTS OF COOTS RELATED TO SEX AND AGE

Measurements of wing, culmen-shield, and metatarsus-midtoe were taken on 299 American coots (Fulica americana) which died during severe spring weather in Iowa. Sexes could not be consis- tently determined by differences in length of culmen-shield, metatarsus-midtoe, or wing. Determination of age by bursal depth proved unsatisfactory, but width and conformation of the bursa were reliable. American coots found dead after a period of severe weather were examined in an at-