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Geology topics

H.K. Nelson

Publications and source records attributed to H.K. Nelson.

16 recordsLinked to original sources
USGS1974

New concepts regarding the production of waterfowl and other game birds in areas of diversified agriculture

Many concepts regarding breeding ecology of waterfowl and the influences of environmental factors on annual production have changed in the past 20 years. These influences are especially pronounced in the prairie region of central North America where agriculture becomes more intensive each year. The principal task assigned to this Research Center when established in 1965 was to determine the relative impact of these influences on production and to identify those facets of breeding biology, nesting habitat requirements and other factors that may be altered to increase production on lands dedicated for this purpose. A corollary objective was to develop methods for enhancing production of waterfowl and other ground-nesting birds on private lands in agricultural areas. Some of the highlights of our findings to date, together with the results from current work of others, provide new information on waterfowl that indicates: (1) homing instincts are not as specific as indicated by earlier workers, (2) there are differences in pioneering between species, sexes and age classes, (3) strength and duration of pair bonds vary by species and age classes, (4) territorial tolerances for most species are greater than previously indicated, (5) there is differential productivity by age classes in some species, (6) there has been a gradual decline in nesting success in the prairie region the past 30 years, (7) adverse influences of intensive agriculture are increasing, (8) mammalian predation is an important factor, (9) high quality, secure nesting habitat and a complex of wetland types are the essential components of an optimum production unit, (10) the size and shape of blocks of nesting cover are important management considerations, (11) overharvest of local breeding populations is becoming a serious problem in some areas. Each of these subjects is discussed as related to research objectives and current management problems. Recommendations are presented for obtaining maximum production of waterfowl and other game birds on public and private lands in agricultural areas.

Book chapter↗
USGS1973

Mercury residues in pintails breeding in North Dakota

Livers of 42 pintail hens ( Anas acuta ) breeding in eastern North Dakota during the spring and early summer of 1969 and 1970 were analyzed for total mercury by the neutron activation technique. Mercury content on a wet weight basis ranged from 0.055 ppm to 9.512 ppm and averaged 0.888 ± 1.796 ppm (SD). Liver mercury levels of hens collected in early spring (prior to planting of crops) were significantly lower than those of hens taken late in the nesting season ( P < 0.01). Mercury residues among prelaying, laying, and postlaying groups collected following the onset of spring planting did not differ significantly ( P > 0.05). Albumen mercury residue was correlated with liver mercury content (r = 0.756, P < 0.05). Mercury content in livers of five wild juveniles averaged 0.123 ± 0.074 ppm.

North Dakota↗
USGS1968

Effect of predator reduction on waterfowl nesting success

A 6-year study to determine the effect of nest-predator removal on waterfowl nesting success was conducted at the Agassiz National Wildlife Refuge in northwestern Minnesota from 1959 through 1964. Predators were removed from the west side of the Refuge while the east side served as a control area. At the end of 3 years, these areas were reversed to reduce the effects of environmental influences. The effect of predator removal was measured by a simulated nest study to determine predation pressure, a check of natural nest success, and weekly breeding pair and brood counts. Results indicated that 60 percent more Class I ducklings were produced on the units where predator control was conducted. Until more is known, reduction of predators to increase waterfowl nesting success should be limited to intensively managed production areas where substantial nest losses are demonstrated.

Minnesota↗
USGS1952

Hybridization of Canada geese with blue geese in the wild

While carrying out hunter bag checks in the vicinity of Sand Lake National Wildlife Refuge, Columbia, South Dakota, during the 1950 waterfowl hunting season, the author examined two adult male geese which proved to be crosses between one of the smaller Canada Geese (possibly Richardson's Goose, Branta canadensis hutchinsi ) and the Blue Goose, Chen caerulescens .

South Dakota↗