Geology topics

D. S. Stolley

Publications and source records attributed to D. S. Stolley.

3 recordsLinked to original sources

USGS2008

Mortality of ducklings of the black-bellied whistling duck (Dendrocygna autumnalis) during their premier swim in a hypersaline lake in south Texas

Adult black-bellied whistling ducks ( Dendrocygna autumnalis ) were observed leaving islands with recently hatched young in a South Texas hypersaline lake during summer 2003. We counted 216 ducklings from 20 broods attempting to make their first swim to the mainland, presumably heading for suitable rearing habitat. Of these, 144 (67%) either died in the water or on the salt-encrusted shoreline within minutes to a few hours of first entering the water. An additional 35 carcasses from unobserved broods were found. Nine carcasses of ducklings were necropsied and they had levels of sodium in the brain above the lethal threshold concentration for sodium poisoning. From our surveillance efforts, we documented a decrease in maximum number of adult black-bellied whistling ducks observed on the islands from 489 in 2002 to 138 in 2003.

South Texas↗

USGS2004

Peracute sodium toxicity in free-ranging black-bellied whistling duck ducklings

From 23 to 25 July 2002, 98–103 newly hatched black-bellied whistling ducks ( Dendrocygna autumnalis ) were observed alive at an inland saline lake (La Sal Vieja) in Willacy County, Texas (USA). Seventy-one (71%) died after showing signs indicative of sodium toxicity within 5 hr of entering the water; some died within minutes. Six carcasses were sent to the United States Geological Survey, National Wildlife Health Center (Madison, Wisconsin, USA) for analysis, and brain sodium levels of all ducklings were above 2,000 parts per million wet weight. More black-bellied whistling duck ducklings are likely to have been affected, but they were not observed after hatching.

Texas↗

USGS1999

Effects of saline drinking water on early gosling development

Relatively high levels of saline drinking water may adversely affect the growth, development, and survival of young waterfowl. Saline drinking water was suspect in the low survival rate of Canada goose (Branta canadensis) goslings at Fish Springs National Wildlife Refuge (FSNWR) in western Utah. Hence, we investigated the effects of saline drinking water on the survival and growth of captive, wild-strain goslings from day 1-28 following hatch. We compared survival and growth (as measured by body mass, wing length, and culmen length) between a control group on tap water with a mean specific conductivity of 650 μS/cm, and 2 saline water treatments: (1) intermediate level (12,000 μS/cm), and (2) high level (18,000 μS/cm). Gosling mortality occurred only in the 18,000 μS/cm treatment group (33%; n = 9). Slopes of regressions of mean body mass, wing length, and culmen length on age were different from each other (P < 0.05), except for culmen length for the intermediate and high treatment levels. We predict that free-ranging wild goslings will experience mortality at even lower salinity levels than captive goslings because of the combined effects of depressed growth and environmental stresses, including hot desert temperatures and variable food quality over summer.

Journal of Wildlife Management↗