Guy A. Baldassarre

Bird species richness within beaver ponds in south-central New York

We surveyed 70 wetlands during winter and spring 1992 to determine the influence of beaver activity on species richness of birds. Wetlands were divided into 3 activity types (active, inactive, potential), and 3 size categories of small (<2.5 ha), medium (≥2.5 <5.0 ha), and large (≥5.0 ha). We recorded 32 species of birds during winter, 20–25 within each activity/size category. There were no differences (P>0.050) among size classes in the average number of species/wetland, but the average was greater (P<0.050) in potential (4.7) versus active sites (3.1). We detected 106 species in spring, 92% of which were in active sites. Active sites also contained the highest (P<0.050) average number of species/wetland (29) compared to inactive sites (24) and potential sites (22). Active sites contained more open water, dead standing trees, surface water, and flooded emergents than inactive or potential sites. Wetland area (log transformed) was most correlated (r=0.43–0.56) with richness of birds in all activity categories. Overall, beaver occupancy of wetlands may have affected bird richness most by creating intermediate ratios of cover:water.

Winter condition of mallards on the Southern High Plains of Texas

Body composition and condition of mallards (Anas platyrhynchos) wintering on the Southern High Plains (SHP) of Texas were studied from October to March 1979-82. Lipid reserves, and usually body weights, of all sex and age classes were lowest in autumn. By mid-winter, however, lipid reserves increased 49-62% for adults and 21-30% for juveniles and averaged 13-18% of body weight. The majority of these reserves (56-100%) were acquired from autumn to early winter. Adults and juvenile females then lost lipids from mid-winter to late winter (9-15%), but juvenile males increased reserves by 20%. Adult females mobilized more lipids than adult males during late winter (15 vs. 9%) and previously had acquired a larger reserve (20 vs. 7%). Body weight and lipids increased before spring migration. Overall, mallards on the SHP maintained better condition than those wintering farther north. J. WILDL. MANAGE. 50(1):52-57 Body weight and carcass composition of waterfowl are not stable during winter (Peterson and Ellarson 1979, Raveling 1979, Reinecke et al. 1982). These changes may be influenced by body condition, which has been defined as an individuals ability to meet present and future needs (Owen and Cook 1977). In this paper we refer to condition as the relationship between an individuals endogenous energy reserves and energy demands for maintenance, productivity, and activity. The SHP of Texas is an agricultural region where wintering mallards have adopted a fieldfeeding strategy; they join northern pintails (A. acuta), American wigeons (A. americana), and green-winged teal (A. crecca) in morning and evening field-feeding flights for waste corn (Baldassarre and Bolen 1984). More than 90% of the diet, by volume, consisted of corn during a 2-year study sampling 324 mallard crops and gizzards (Moore 1980). Corn is higher in energy than seeds of native plants occurring in the numerous playa lakes that serve as wetland habitat for waterfowl on the SHP (Baldassarre et al. 1983). This high energy content influences body condition as available carbohydrates are converted into endogenous lipids (Hazelwood 1976). Lipids, in turn, become important reserves used by birds during periods of winter stress (Blem 1976). However, although mallards wintering on the SHP have access to high energy foods, they also encounter temperature stress during certain periods (Whyte and Bolen 1984). The objective of this study was to determine the relationship between winter stress and carcass composition, especially lipid reserves, of mallards wintering on the SHP. Financial support was provided by the Caesar Kleberg Found. Wildl. Conserv. and the U.S. For. Serv. (F. A. Stormer, Proj. Leader, Great Plains Wildl. Habitat Res. Lab.). J. D. Myrick, J. R. Davis, C. L. Lee, H. A. McLain, D. W. Brown, W. J. Hill, and T. J. Hill granted access to private property. R. J. Baker, K. T. Scribner, J. J. Juen, E. E. Quinlan, G. E. Huber, R. H. Lunn, and R. D. Godfrey aided collection of mallards during hunting seasons. R. D. Godfrey, J. A. Templer, and J. J. Peterson assisted with laboratory work. L. J. Celentano and D. B. Webster provided advice during statistical and computer analysis of the data. We are grateful to all. This is contribution T-9-370 of the Coll. Agric. Sci., Texas Tech Univ., Lubbock.

Effects of saline water on growth and survival of mottled duck ducklings in Louisiana

We studied the effects of saline drinking water on the growth and survival of penned mottled duck (Anas fulvigula) ducklings at Rockefeller Wildlife Refuge in southwestern Louisiana in 1989. Duckling mortality at different salinities was 100% at 18 ppt, 90% at 15 ppt, and 10% at 12 ppt. No ducklings died within treatments of <12 ppt, but the growth rate of ducklings in the 12-ppt treatment was lower (P _ 0.05) than all lower salinity treatments. When ducklings were given 12-ppt salinity water and exercised, mortality would have exceeded 70%. Initial lethargy shown by ducklings in the 9-ppt treatment, combined with potentially high mortality of ducklings given 12-ppt salinity water and exercised, suggested that the upper salinity threshold tolerated by wild mottled duck broods lies within this range. We advocate creation and management of semi-impoundments in coastal Louisiana and Texas to prevent deterioration and/or loss of marshes of <9-ppt salinity to provide quality habitat for mottled duck broods and other species of flora and fauna dependent on these marshes. J. WILDL. MANAGE. 55(3):471-476 The mottled duck is a nonmigratory species occupying a restricted range in North and Central America. Isolated populations occur in Florida, central Mexico, and the coastal marshes from Mississippi westward to northern Veracruz, Mexico (Bellrose 1980). However, the greatest number (98%) of mottled ducks occurs in coastal marshes of Louisiana and Texas where there is an estimated breeding population of 110,000 (Stutzenbaker 1988). There is concern about the mottled duck because annual surveys conducted in Louisiana have indicated a 44% decline from 1971 to 1983 (Stutzenbaker 1988). Stutzenbaker (1988) hypothesized that the loss and deterioration of remaining habitat in both Texas and Louisiana might be responsible. Saltwater intrusion, in particular, has caused significant habitat changes in Louisiana marshes. From 1968 to 1978, for example, freshwater marsh vegetation decreased and saline vegetation increased, especially in areas transected by large canals (Chabreck and Linscombe 1982). Furthermore, saline drinking water may affect the condition of both adult and juvenile waterfowl (Windingstad et al. 1987, Tiejte and Teer 1988). Ducklings are even less tolerant of salt water than adult birds because their salt glands are poorly developed, especially at <6 days of age (Ellis et al. 1963, Schmidt-Nielsen and Kim 1964, Riggert 1977). Mallard ducklings, for instance, suffered mortality, reduced growth, and a variety of sublethal physiological abnormalities when exposed to high concentrations of sodium sulfate, magnesium sulfate, and saline water occurring in natural wetlands in Saskatchewan (Mitcham and Wobeser 1988a,b). In North Dakota, wild ducklings concentrated and fed around freshwater seepages on saline lakes (Swanson et al. 1984). Female mottled ducks often bypass less productive areas of marsh close to the nest while leading ducklings to more productive broodrearing areas (Baker 1983). Therefore, ducklings traveling through, or remaining in, marshes affected by saltwater intrusion could suffer decreased survivorship. Our study determined the effects of saline water on the growth and survival of mottled duck ducklings. We hypothesized that survivorship, growth rates, and levels of body mass and carcass components would decrease as salinity levels increased. Financial support was provided by private corporations and landowners concerned with wetland management in the Louisiana coastal zone. We are extremely grateful to R. G. Vincent, Jr., from the Miami Corp., B. N. Kirkpatrick from the J. G. Gray Estate, W. P. Hardeman from the Amoco Production Co., J. P. Donohue from the Vermilion Corp., T. Wright from the Sweetlake Land and Oil Co., and J. Woddard from the FINA Oil and Chemical Co. J. T. Joanen and W. G. Perry provided assistance and ideas throughout the study. W. M. Shields and L. W. VanDruff reviewed the manuscript, and

A method for sampling waste corn

De nombreux animaux (cervides, faisans, etc.) se nourrissent sur les grains laisses sur le sol apres la recolte. Il est interessant de comparer la disponibilite de cette nourriture et de la mesurer pour des champs exploites par diverses techniques

Harvest and Food Habits of Waterfowl Wintering in Sinaloa, Mexico

Agencies, 38:158-164. .1986. Changes in body weight and body composition of breeding ring-necked ducks (Aythya collaris). Auk, 103:181-188. HOHMAN, W. L., AND B. L. CYPHER. 1986. Ageclass determination of ring-necked ducks. J. Wildl. Manage., 50:442-445. HOHMAN, W. L., T. S. TAYLOR, AND M. W. WELLER. 1988. Annual body weight change in ring-necked ducks (Aythya collaris). Pp. 257-269, in Waterfowl in winter (M. W. Weller, ed.). Univ. Minnesota Press, Minneapolis. HOHMAN, W. L., D. W. WOOLINGTON, AND J. H. DEVRIES. 1990. Food habits of wintering canvasbacks in Louisiana. Can. J. Zool., 68:2605-2609. HOPPE, R. T., L. M. SMITH, AND D. B. WESTER. 1986. Foods of wintering diving ducks in South Carolina. J. Field Onithol., 57:126-134. KELLEY, J. R., AND L. H. FREDRICKSON. 1991. Chufa biology and management. U.S. Fish Wildl. Serv., Fish Wildl. Leafl. No. 13.4.18. PETERS, M. S. 1992. Effects of deep tillage on redistribution of lead shot and chufa tuber biomass

Incidence of Second Broods by Wood Ducks in Alabama and Georgia

Second brood production by wood ducks (Aix sponsa) nesting in eastcentral Alabama and westcentral Georgia was -6.9 and 11.5% of successful nests in 1985 and 1986, respectively. There was a negative correlation (r = -0.86) between latitude and percent of hens producing second broods. Second broods increased production of flight-stage birds an estimated 1.1-2.6% in 1985 and 2.0-4.7% in 1986. The interval between hatch of the first clutch and initiation of the second clutch was 15-51 days in 1985 and 17-72 days in 1986. Thus, because wood duck females remain with their broods from 31 to 60 days, we concluded that some females that double-brooded either abandoned the first brood to initiate a second nest, initiated the second nest concurrent with brood rearing, or initiated the second nest after loss of the first brood. J. WILDL. MANAGE. 52(3):426-431 Most species of birds raise only 1 brood/year because time required for courtship, nest-building, incubation, and rearing young precludes fledging a second brood during the breeding season. However, some groups such as passeriforms and columbiforms regularly fledge >2 broods/reproductive period (Lack 1968, Westmoreland et al. 1986). Waterfowl normally do not hatch >1 clutch/ season, but many species renest if the first clutch is destroyed (Bellrose 1980). Wood ducks are an exception; however, because production of 2 broods has been recorded with regularity (Fredrickson and Hansen 1983). Double-brooded females were those that successfully hatched 2 broods in 1 reproductive season (Fredrickson and Hansen 1983). Brood survival was not assumed, although some ducklings from first and second broods of double-brooded females ultimately survived to flight stage. Fredrickson and Hansen (1983) also noted that existing reports of second broods were from above 36*N latitude and suggested that the frequency of double broods may be higher farther south. In passerines, for example, 2 species of thrushes (Turdus merula and T. philomelos) nesting in northern Europe fledge only 1 brood/ season, but conspecifics nesting farther south fledge 2-3 broods/season (Mayer-Gross and Perrins 1962). The objectives of our study were to document the frequency of second broods by wood ducks nesting in eastcentral Alabama and westcentral Georgia, assess the effect of latitude on the occurrence of second broods, and estimate the contribution of second broods to production. We thank D. E. Temple, W. D. Rundle, and the staff at Eufaula National Wildlife Refuge for their interest and assistance during this project. M. K. Causey, R. E. Mirarchi, and N. R. Holler reviewed the manuscript. This project was funded by the Alabama Division of Game and Fish through Federal Aid in Wildlife Restoration, Project W-44. This is publication 15871210 of the Alabama Agricultural Experiment Station.

The Frequency of Sarcocystis spp. and Its Effect on Winter Carcass Composition of Mottled Ducks

Macrocysts of the protozoan parasite Sarcocystis spp. occurred in 34 of 241 (14%) adult and 6 of 70 (8.6%) immature mottled ducks (Anas fulvigula) that were collected in southwestern Louisiana from 1987 to 1989. The prevalence of Sarcocystis spp. among immature ducks was higher than previously reported, possibly because of a longer exposure period. No differences in carcass composition variables were found between heavily infected and uninfected adult mottled ducks during the winter period of the annual cycle. We concluded that macrocysts of Sarcocystis spp. did not influence carcass composition and probably exert negligible effects on survival of parasitized mottled ducks during winter.