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George F. Gee

Publications and source records attributed to George F. Gee.

6 recordsLinked to original sources
USGS2003

Motorized migrations: The future or mere fantasy?

In 15 experiments from 1993-2002, we led cranes, geese, or swans on their first southward migration with either ultralight aircraft or vehicles on the ground. These experiments reveal that large birds can be readily trained to follow and most will return north (and south) in subsequent migrations unassisted. These techniques can now be used to teach birds new (or forgotten) migration paths. Although we are constantly improving our training techniques, we now have an operational program that can be broadly applied to those species where juveniles learn migration routes from their parents.

Arizona, Florida, Idaho, Indiana, Maryland, New Me↗
USGS1995

Mississippi sandhill cranes

Resident sandhill cranes formed a continuous population in Georgia and Florida and widely separated populations along the Gulf Coastal Plain of Texas, Louisiana, Mississippi, and Alabama (Figure). The Mississippi sandhill crane ( Grus canadensis pulla ) was one of the widely separated populations on the Coastal Plain that bred in pine savannas in southeastern Mississippi, just east of the Pascagoula River to areas just west of the Jackson County line, south to Simmons Bayou, and north to an east-west line 8-16 km (5-10 mi) north of VanCleave. Agricultural and industrial development including World War II ship building, fire suppression, and forestry practices destroyed much of the sandhill crane's habitat in Jackson County, Mississippi. The U.S. Fish and Wildlife Service (USFWS) added the Mississippi sandhill crane to the endangered species list in 1973 and established the Mississippi Sandhill Crane National Wildlife Refuge in 1974. The USFWS began captive breeding at the Patuxent Wildlife Research Center (PWRC) in 1965 to protect the subspecies during habitat restoration and to provide stock for reintroduction. Morphological, physiological, and genetic differences exist among crane subspecies (Aldrich 1972). Mississippi birds mature earlier and begin egg production about 6 weeks later than Florida sandhill cranes. Genetic studies (Dessauer et al. 1992; Jarvi et al. 1994) show a level of heterozygosity (see glossary) in the wild Mississippi population about half that in other sandhill cranes. As in other small populations, cranes seem to have genetic weaknesses. In the captive population, for example, 17% of all birds die from detectable heart murmurs and when released to the wild, 36% with heart murmur and 83% without heart murmurs survive for 1 year after release.

Book chapter↗
USGS1994

Environmental contaminants in nonviable eggs of the endangered Mississippi sandhill crane (Grus canadensis pulla)

Our objectives were to determine if concentrations of environmental pollutants and microbial contamination in nonviable eggs of the endangered Mississippi sandhill crane ( Grus canadensis pulla ) contributed to egg failure. Six eggs collected in 1990 and four in 1991 contained only background levels of organochlorine pesticides and polychlorinated biphenyls (PCBs), and tests for microbial contamination were all negative. Two eggs contained late dead embryos, but neither revealed obvious abnormalities. Three eggs contained potentially harmful concentrations (23, 39, 146 pg/g, wet mass) of polychlorinated dibenzo- p -dioxins (PCDDs) and dibenzofurans (PCDFs), based on 2,3,7,8-tetrachlorodibenzo- p -dioxin equivalents (TCDD-EQ) for combined compounds. Because of the scarcity of material suitable for laboratory examination and the endangered status of the crane, we recommend that nonviable eggs continue to be monitored for toxic pollutants.

Mississippi↗
USGS1992

Establishing paternity in Whooping Cranes ( Grus americana ) by DNA analysis

DNA fingerprinting was used to study paternity and genetic variability within a captive flock of Whooping Cranes ( Grus americana ). Fingerprint patterns for 42 individuals were obtained by digesting genomic crane DNAs with Hae III followed by electrophoresis, blotting, and hybridization to the M13 minisatellite probe. Despite finding reduced levels of genetic variation in the Whooping Crane due to a population "bottleneck," these polymorphisms were successfully used to determine paternity in six of seven cases of captive propagation where the maternal-offspring relationship was known, but where the sire was unknown. These determinations of paternity are required for effective genetic management of the crane flock. These results also revealed a number of heterozygous minisatellite loci that will be valuable in future assessments of genetic variability in this endangered species.

The Auk↗
USGS1981

Species differences in hematological values of captive cranes, geese, raptors, and quail

Hematological and serum chemical constituents of blood were determined for 12 species, including 7 endangered species, of cranes, geese, raptors, and quail in captivity at the Patuxent Wildlife Research Center. Means, standard deviations, analysis of variance by species and sex, and a series of multiple comparisons of means were derived for each parameter investigated. Differences among some species means were observed in all blood parameters except gamma-glutamyl transpeptidase. Although sampled during the reproductively quiescent period, an influence of sex was noted in red blood cell count, hemoglobin, albumin, glucose, cholesterol, serum glutamic oxaloacetic transaminase, Ca, and P. Our data and values reported in literature indicate that most hematological parameters vary among species and, in some cases, according to methods used to determine them. Therefore, baseline data for captive and wild birds should be established by using standard methods, and should be made available to aid others for use in assessing physiological and pathological conditions of these species.

Journal of Wildlife Management↗