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Geology topics

D.G. Smith

Publications and source records attributed to D.G. Smith.

33 records · Page 2Linked to original sources
USGS1992

Progress in satellite tracking cranes

We review the history of tracking cranes with satellite telemetry and identify some of the difficulties in designing satellite transmitters and harnesses for cranes. Miniaturization of these transmitters and a plethora of harnessing experiments since 1989 allow us to recommend limited application of this technology to all species of cranes. We are still uncertain, however, if cranes harnessed with satellite telemetry devices are able to reproduce after migration. Because of this uncertainty, we urge caution in the use of this technology, especially with breeding adults in severely endangered populations. This manuscript also describes continuing research needs.

Book chapter↗
USGS1992

Population recovery of the Whooping Crane with emphasis on reintroduction efforts: Past and future

The U.S. Fish and Wildlife Service (USFWS) began building a captive whooping crane (Grus americana) colony at Patuxent Wildlife Research Center (Patuxent), Maryland, in 1966. From 1976 to 1984, 73 eggs from this colony and 216 eggs from Wood Buffalo National Park (Wood Buffalo), Canada, nests were placed in sandhill crane (G. canadensis) nests at Grays Lake National Wildlife Refuge (Grays Lake), Idaho, the site of the first whooping crane reintroduction attempt. Although 84 chicks fledged from the 289 eggs, the egg transfer program has been discontinued because of inordinately high mortality (only ca. 13 birds remain in the wild in 1991) and lack of breeding in survivors. In recent decades new methods have emerged for introducing captive-produced offspring to the wild. Surrogate studies with sandhill cranes, particularly the endangered Mississippi sandhill cranes (G. c. pulla), have shown that young cranes, raised either by captive, conspecific foster parents, or by costumed humans and in close association with live cranes and lifelike crane taxidermic dummies, have high post-release survival rates. These techniques will likely be used in future whooping crane reintroduction programs. Current recovery objectives for the whooping crane include expansion of the 2 captive colonies, establishment of a third captive colony in Canada, and reintroduction of 2 additional wild populations. The Kissimmee Prairie in central Florida has been selected for the next release experiment. Evaluation of this site began in 1984, and risk assessment is expected to begin in 1992 with the transfer and monitoring of a group of captive-reared, juvenile whooping cranes. These 'tests of the environment' will, if results are favorable, be followed by a full-scale reintroduction effort of at least 20 birds/year beginning in 1994 or 1995.

Book chapter↗
USGS1992

Techniques for rearing and releasing nonmigratory cranes: Lessons from the Mississippi Sandhill Crane program

Captive-reared Mississippi sandhill cranes (Grus canadensis pulla) reared at the Patuxent Wildlife Research Center (Patuxent) have been released at the Mississippi Sandhill Crane National Wildlife Refuge (MSCNWR) since 1981. Of 131 birds released through December 1990, 103 were reared by foster parents. The remaining 28 were experimentally hand-reared in 1989 and 1990. After refining release procedures, parent-reared birds have integrated into the wild flock, many have survived, and some have bred. Releases of hand-reared cranes elsewhere in the 1970's were largely unsuccessful, at least in part due to the lack of a lengthy acclimation period. A new hand-rearing protocol holds promise in producing release-worthy birds. The technique employs some features first used in the 1960's (e.g., a costume for the human caretaker and model crane heads used to train chicks to feed). In the mid-1980's, the following features were added: (1) the costumed caretaker was given a visor and feathers, (2) a taxidermic crane head or a hand puppet was held or suspended from the ceiling for use in stimulating chicks to feed, (3) a taxidermic mount of a brooding crane supplied warmth, (4) a full-sized live crane was maintained in an adjacent pen and in visual contact with neonatal young to provide an imprinting model, and (5) a small group of adult (or subadult) cranes was penned adjacent to the outdoor chick pens to provide socialization models. Recent releases of Mississippi sandhill cranes hand-reared according to this protocol and released in Mississippi have had high first-year survival rates. The now-operational technique holds promise for producing large numbers of release-worthy birds.

Book chapter↗
USGS1992

Determining sex of eastern screech-owls using discriminant function analysis

Seven morphometric characteristics and weight of males and females of a captive colony of Eastern Screech-Owls (Otus asio) were compared. Females were significantly larger than males in weight, total length, and length of tail, wing and bill. A discriminant function analysis based on weight, wing and tail length correctly identified the sex of 88% of the 77 birds.

Journal of Raptor Research↗
USGS1990

[Book review] Return of the Whooping Crane

Fewer than 40 years ago, Life magazine ran an article decrying the plight of Whooping Cranes ( Grus americana ) on their wintering grounds at Aransas National Wildlife Refuge (Aransas) along the Gulf Coast. The small flock of approximately 20 birds that summered at Wood Buffalo National Park (Wood Buffalo) in Canada and wintered on the Texas coast at Aransas comprised the entire wild population of the species-a population that at the time seemed to be drifting inexorably to- ward extinction. Today, the Aransas/Wood Buffalo flock numbers more than 140 birds, there are more than 30 birds in captivity at the Patuxent Wildlife Research Center (Patuxent), and another 20-plus birds at the International Crane Foundation in Baraboo, Wisconsin. There are also a dozen wild birds in an experimental flock (termed the Rocky Mountain flock by Doughty) that winters at Bosque Del Apache National Wildlife Refuge (NWR) in New Mexico and summers in the mountain valleys centered on Grays Lake NWR in Idaho.

The Auk↗
USGS1990

Owls

Eight species of owls regularly occur and may breed in one or more of the southeastern states. Several additional northern or western species appear irregularly as accidentals or during years of southward incursions. In the Southeast, the most common and wide- spread owls are the common barn-owl, eastern screech-owl, great horned owl and barred owl; the most restricted is the burrowing owl. The long-eared, short-eared, and northern saw-whet owls are primarily winter visitors in this region, although small and very localized nesting populations of short-eared owls may occur in Virginia. Long-eared owls and northern saw-whet owls may occur in West Virginia and northern saw-whet owls may occur in the highlands of Tennessee and North Carolina. Several owls of the Southeast are Blue-listed as threatened, endangered, or of local concern, including the common barn-owl, eastern screech-owl, burrow'ing owl and short-eared owl. The nesting status of the long-eared owl and northern saw-whet owl are still poorly known. These two owls should be included on stat and regional lists of species of special concern. Important limiting factors for all owls of the Southeast include habitat loss and human related mortality. Management issues center on obtaining a data base useful in predicting the effects of current forest management practices on owl populations and encouraging use of forestry techniques that least impact owls. Research needs include initiating studies of all aspects of the life history and habitat relationships of each owl species.

Book chapter↗
USGS1990

Raptor road surveys in South America

Twenty-six (23 traveling and three point) raptor roadside surveys were conducted during a 29,000 km expedition through nine nations of South America. During roadside surveys, we tallied 41 of the 87 (47%) diurnal raptor species (including vultures) that occur in South America. The number of species observed per route varied from 17 in the wet savanna of Venezuela to only two species recorded in the harsh Atacama Desert and the dry montane grasslands of Chile and Peru. Raptor density (non-vultures) varied from 1 per 67 km in the Atacama Desert to more than 1 per km in agricultural areas where caracaras and other species that utilize disturbed habitats were common. Responses of raptor communities to deforestation and other habitat disturbances are discussed. While certain habitat modifications potentially increase raptor abundance and diversity, the alteration of primary forest has the opposite effect, at least on diversity.

Journal of Raptor Research↗
USGS1989

Snowy owl

The snowy owl is a rare to uncommon, irregular winter visitor in the northeastern United States, decreasing southward in abundance except during incursion years, when it is more common and widely distributed. Although snowy owls are recorded in northern New England every winter, major incursions occur at approximately three to four year intervals. Limiting factors include food, habitat and human interference. Research is needed on the population ecology of this species and, perhaps more important, management goals must be directed towards public education emphasizing the value of snowy owls.

Book chapter↗
USGS1988

Crested caracara

The crested caracara's range extends from the southern United States south to Tierra del Fuego. Although the caracara has been recorded in all of the southwestern states, it occurs regularly only in southern Arizona and central, southern and coastal Texas. Its distribution is closely linked to the availability of carrion. Throughout its range, thecaracara is associated with open habitats such as desertscrub, grassland and savanna. Nesting pairs usually produce one brood each breeding season, which extends from December through August. Eggs are laid from March into early June and clutch size averages two to three eggs. Young fledge in June and July and may remain with the adults for several weeks. Management recommendations for the crested caracara include clarifying its status in the Southwest. using supplemental feeding and modifying habitats to encourage recolonization of previously occupied areas and movement into new areas.

Book chapter↗
USGS1988

Raptors and aircraft

Less than 5% of all bird strikes of aircraft are by raptor species, but damage to airframe structure or jet engine dysfunction are likely consequences. Beneficial aircraft-raptor interactions include the use of raptor species to frighten unwanted birds from airport areas and the use of aircraft to census raptor species. Many interactions, however, modify the raptor?s immediate behavior and some may decrease reproduction of sensitive species. Raptors may respond to aircraft stimuli by exhibiting alarm, increased heart rate, flushing or fleeing and occasionally by directly attacking intruding aircraft. To date, most studies reveal that raptor responses to aircraft are brief and do not limit reproduction; however, additional study is needed.

Book chapter↗
USGS1988

Whooping crane recovery: Progress through research

Cooperative efforts of the Canadian Wildlife Service (CWS), U.S. Fish and Wildlife Service (FWS), Wood Buffalo National Park in Canada, and Patuxent Wildlife Research Center have established a captive flock of whooping cranes, and at least two additional wild populations. Efforts have focused on research, habitat protection, law enforcement, and conservation education programs.

Zooview↗
USGS1986

An overview of raptor conservation in Latin America

Prior to the last decade, biological studies of raptorial birds in Latin America were almost nonexistent. For many species little more was known than their general range and habitat type. The last few years have seen the opening of a door to what will surely be a flood of scientific investigations. Ultimately, the survival of raptor communities in Latin America depends not only on research but also on several other equally significant conservation efforts. These typically appear in the following order: first, appropriate legislation must be enacted and enforced to provide legal protection; second, the public must be educated concerning the value of wildlife; third, substantial blocks of favourable habitat must be identified and preserved; fourth, economic incentives must be generated so that the local human populations actually benefit from the preservation of vulnerable wildlife and natural habitats; and finally, the long-term success of all of these efforts in each nation depends on the attainment of political, economic and social stability.

Birds of Prey Bulletin↗