Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 31 - 48 of 48

Full-Text Articles in Life Sciences

Counting Cranes: How Much Effort Is Enough?, Douglas H. Johnson, Roderick C. Drewien, Douglas S. Benning Jan 2001

Counting Cranes: How Much Effort Is Enough?, Douglas H. Johnson, Roderick C. Drewien, Douglas S. Benning

Proceedings of the North American Crane Workshop

Accurate population estimates of sandhill cranes (Grus canadensis) are important because management decisions, such as establishing hunting regulations, are based on those estimates. Counts often are made during aerial surveys when the cranes are congregated. A complete census may be feasible if the area to be surveyed is small and adequate resources are available. For large areas, resources may be inadequate for a census so partial counts (sample surveys) are made. Because cranes are gregarious, the counts in a sample of units may contain either a disproportionately large, or a disproportionately small, fraction of the total, leading to …


Tracking Sandhill Crane Migration From Saskatchewan To The Gulf Coast, Dale G. Hjertaas, David H. Ellis, Brian W. Johns, Stacie L. Moon Jan 2001

Tracking Sandhill Crane Migration From Saskatchewan To The Gulf Coast, Dale G. Hjertaas, David H. Ellis, Brian W. Johns, Stacie L. Moon

Proceedings of the North American Crane Workshop

Four adult sandhill cranes (Grus canadensis rowani) were captured in east-central Saskatchewan, equipped with transmitters, and tracked by satellite to detennine if their migration routes and wintering areas would allow their use as guide birds to establish a new migratory flock of whooping cranes (G. americana). Two birds captured near Yorkton died or their transmitters were lost before migration. Two adults from the Overflowing River moved to staging areas in southern Saskatchewan in September. By 29 September, Crane A left Saskatchewan and moved to North Dakota where it remained until late October. By 21 December, it …


Whooping Crane Egg Management: Options And Consequences, David H. Ellis, George F. Gee Jan 2001

Whooping Crane Egg Management: Options And Consequences, David H. Ellis, George F. Gee

Proceedings of the North American Crane Workshop

Eggs to build captive whooping crane (Grus americana) flocks and most eggs for reintroduction experiments have come from second viable eggs in 2-egg clutches in Canada. Four years ago, egg removal ceased. Based on reproductive rates for years when second eggs were removed and for years when eggs were not removed, we project numbers of young fledging in the wild and in captivity for the 2 most likely egg-management strategies. From existing data sets, we find that reproductive performance was, on average, better during the era of routine removal of the second viable eggs than when no manipulation …


Interactions Of Sandhill Cranes And Whooping Cranes With Foreign Objects In Florida, Martin J. Folk, Stephen A. Nesbitt, Marilyn G. Spalding Jan 2001

Interactions Of Sandhill Cranes And Whooping Cranes With Foreign Objects In Florida, Martin J. Folk, Stephen A. Nesbitt, Marilyn G. Spalding

Proceedings of the North American Crane Workshop

During studies of Florida sandhill cranes (Grus canadensis pralensis), greater sandhill cranes (G. c. tabida), and whooping cranes (G. americana) in Florida, we documented cases where these birds were in contact with human-produced objects that resulted in injury or death. We describe >40 instances in which cranes collided with powerlines or fences, became entangled in string or fishing line, or ingested foreign objects. The effect of human-produced objects on crane populations, particularly small populations, may be significant.


Distribution, Abundance, And Reproduction Of The Cuban Sandhill Crane (Grus Canadensis Nesiotes), Xiomara Galvez Aguilera, Vicente Berovides Alvarez, Jose Rivera Rosales Jan 2001

Distribution, Abundance, And Reproduction Of The Cuban Sandhill Crane (Grus Canadensis Nesiotes), Xiomara Galvez Aguilera, Vicente Berovides Alvarez, Jose Rivera Rosales

Proceedings of the North American Crane Workshop

We discuss the distribution, abundance, and reproduction of the Cuban sandhill crane (Grus canadensis nesiotes). This is an overview of a 5-year study conducted by the National Organization for the Protection of Flora and Fauna of the Ministry of Agriculture for the Republic of Cuba and assisted by the International Crane Foundation and Brehm Fund. The distribution of this subspecies was determined by visiting potential sites and areas where this race has previously been reported. Nine new populations were found. This brings the total to 11 on the Isle of Cuba, 1 on Cayo Romano, and 2 on …


Hematological And Serum Chemistry Norms For Sandhill And Whooping Cranes, Glenn H. Olsen, Melina M. Hendricks, Lindsay E. Dressler Jan 2001

Hematological And Serum Chemistry Norms For Sandhill And Whooping Cranes, Glenn H. Olsen, Melina M. Hendricks, Lindsay E. Dressler

Proceedings of the North American Crane Workshop

The nonnal values used as a diagnostic tool and for comparison of cranes were established in the early 1970's. In that early study, no effort was made to look at factors such as age, sex, or subspecies. In addition, during the early study disease problems (primarily disseminated visceral coccidiosis) and nutritional problems were undiagnosed and uncontrolled. For 2 years during the annual health examinations of cranes at the USGS Patuxent Wildlife Research Center (patuxent), we collected blood from healthy cranes for analysis. We found significant differences between the values reported from the 1970's and the values seen in this study …


Ingested Metal In Whooping Cranes: An Endoscopic Technique For Removal And Implications For The Release Program, Glenn H. Olsen, Michael Wise Jan 2001

Ingested Metal In Whooping Cranes: An Endoscopic Technique For Removal And Implications For The Release Program, Glenn H. Olsen, Michael Wise

Proceedings of the North American Crane Workshop

Since 1993 when the whooping crane (Grus americana) release program in Florida started, 21 whooping cranes at the USGS Patuxent Wildlife Research Center (patuxent) have been diagnosed with gastrointestinal foreign bodies (primarily metal objects). A technique for safely removing these objects has been developed. The technique uses a flexible gastric endoscope to enter the proventriculus or ventriculus, and a snare or forceps passed down a channel of the endoscope to retrieve the foreign bodies. The technique is very successful, with the whooping crane usually back to its pen the next day. The longterm survival of the whooping cranes …


Sandhill Crane Nest And Egg Characteristics At Malheur National Wildlife Refuge, Oregon, Carroll D. Littlefield Jan 2001

Sandhill Crane Nest And Egg Characteristics At Malheur National Wildlife Refuge, Oregon, Carroll D. Littlefield

Proceedings of the North American Crane Workshop

For the period 1969-89, greater sandhill crane (Grus canadensis tabida) nest and egg characteristics were assessed for pairs on the Malheur National Wildlife Refuge (Malheur), Oregon. Nests mostly were in broad-fruited burreed (Sparganium eurycarpum) and hardstem bulrush (Scirpus acutus) and were constructed primarily of the same vegetative species that surrounded nests. Averages for nest parameters were diameter 127 xIII cm, crown diameter 77 x 69 cm, bowl diameter 41 x 37 em, bowl depth 5.8 em, nest height 12.4 em, and water depth 25.8 cm. Nests were placed in vegetation with a mean height …


A Comparison Of Behavior For Two Cohorts Of Captive-Reared Greater Sandhill Cranes Released In Northern Arizona, Daniel P. Mummert, Carol L. Chambers, David H. Ellis Jan 2001

A Comparison Of Behavior For Two Cohorts Of Captive-Reared Greater Sandhill Cranes Released In Northern Arizona, Daniel P. Mummert, Carol L. Chambers, David H. Ellis

Proceedings of the North American Crane Workshop

To determine how the behavior of greater sandhill cranes (Grus canadensis tabida) changes according to time of year, time of day, and number of days after release, we observed the activities of 2 groups of captive-reared greater sandhill cranes at Mormon Lake, northern Arizona. The behaviors we compared were alert, loafing, sleeping, foraging, preening, locomotion, and other. We found costume-reared subadult greater sandhill cranes that were established at the study site for a year spent more time foraging and being alert towards predators than parent -reared juvenile greater sandhill cranes that were recently released from captivity. We also …


Natural Fertility In Whooping Cranes And Mississippi Sandhill Cranes At Patuxent Wildlife Research Center, Jane M. Nicolich, George F. Gee, David H. Ellis, Scott G. Hereford Jan 2001

Natural Fertility In Whooping Cranes And Mississippi Sandhill Cranes At Patuxent Wildlife Research Center, Jane M. Nicolich, George F. Gee, David H. Ellis, Scott G. Hereford

Proceedings of the North American Crane Workshop

The first fertile whooping crane (Grus americana; WC) egg produced through natural breeding at Patuxent Wildlife Research Center (patuxent) was laid in 1991. Prior to that time, all fertile whooping crane eggs were the result of artificial insemination. Since 1991, eight different whooping crane pairs at Patuxent have produced fertile eggs through natural breeding. Mean fertility averages over years for each pair range from 40% to 93 %. Fertility rates for each pair also vary greatly between years, from 0% to 100%, but the causes of the variance are unknown. Experiences with natural fertility in Mississippi sandhill cranes ( …


Resolutions Passed By The North American Crane Working Group Eighth North American Crane Workshop, Albuquerque, New Mexico U.S.A. Jan 2001

Resolutions Passed By The North American Crane Working Group Eighth North American Crane Workshop, Albuquerque, New Mexico U.S.A.

Proceedings of the North American Crane Workshop

Participants of the Eighth North American Crane Workshop hereby express their thanks and appreciation to the Bosque del Apache National Wildlife Refuge for hosting this workshop, to the staff of the Sheraton Old Town Hotel, to the field trip leaders, to the staff of the Bernardo Waterfowl Management Area, and to the committees and individuals who made the workshop a success. The paper sessions were excellent, and the spirit of friendship and dedication to crane conservation among the participants was revitalizing. Special thanks go to NACWG President Scott Hereford and Bosque del Apache Biologist John Taylor for their tireless effort …


Recommendations For The Attachment Of Satellite Transmitters To Cranes, David H. Ellis, Paul W. Howey, Gary L. Krapu Jan 2001

Recommendations For The Attachment Of Satellite Transmitters To Cranes, David H. Ellis, Paul W. Howey, Gary L. Krapu

Proceedings of the North American Crane Workshop

Recent advances in miniaturization of satellite transmitters have resulted in thumb-sized packages weighing less than 30 g. These are smaller than VHF radios routinely mounted on crane leg bands. With this development and with favorable signal reception results, there is no need for, and much to recommend against, the continued use of back-pack mounts. We provide details for leg-mount attachments.


Population Genetics Of Midcontinent Sandhill Cranes, Jessica L. Petersen, Richard Bischof, Allen L. Szalanski Jan 2001

Population Genetics Of Midcontinent Sandhill Cranes, Jessica L. Petersen, Richard Bischof, Allen L. Szalanski

Proceedings of the North American Crane Workshop

The Midcontinent Sandhill Crane Population is comprised of 3 subspecies, lesser (Grus canadensis canadensis), Canadian (G. c. rowani), and greater (G. c. tabida) sandhill cranes. In conjunction with the USGS Northern Prairie Wildlife Research Center, we studied the extent of genetic variation between and within each race of the Midcontinent Sandhill Crane Population. DNA was extracted from 150 feather and dried blood samples collected from 1995-99 from sandhill cranes in the Platte River Valley, central Nebraska. Parsimony and maximwn likelihood analysis of the mtDNA D-loop sequences (ca 675 bp amplified using PCR) from 29 …


An Update Of The Florida Whooping Crane Release Project Through June 2000, Stephen A. Nesbitt, Martin J. Folk, Kathleen A. Sullivan, Stephen T. Schwikert, Marilyn G. Spalding Jan 2001

An Update Of The Florida Whooping Crane Release Project Through June 2000, Stephen A. Nesbitt, Martin J. Folk, Kathleen A. Sullivan, Stephen T. Schwikert, Marilyn G. Spalding

Proceedings of the North American Crane Workshop

Whooping cranes (Grus americana) reared mostly at the USGS Patuxent Wildlife Research Center (patuxent) or the International Crane Foundation (ICF) have been released in Florida in an effort to reestablish a nonmigratory population in the southeastern United States. From 1993 through spring of 2000, we released 208 cranes. Modifications to the release procedure instituted in 1995 have greatly reduced mortality from the initial release period. First year mortality has averaged 50%. A longterm drought that began after spring 1998 may have contnbuted to increased first year mortality in recent years. Most mortality has been from predation, mostly bobcat …


Fate Of The Survivors Of The 1995 And 1996 Arizona Trucking Migrations Of Costume-Reared Greater Sandhill Cranes, Daniel P. Mummert, David H. Ellis, Carol L. Chambers Jan 2001

Fate Of The Survivors Of The 1995 And 1996 Arizona Trucking Migrations Of Costume-Reared Greater Sandhill Cranes, Daniel P. Mummert, David H. Ellis, Carol L. Chambers

Proceedings of the North American Crane Workshop

In 1995 and 1996, we trained 2 groups of costume-reared greater sandhill cranes (Grus canadensis tabida) (10 in 1995, 14 in 1996) to follow a truck. Thereafter we led 10 in 1995 and 12 in 1996 from Garland Prairie, northern Arizona, to the Buenos Aires National Wildlife Refuge, southern Arizona (ca. 620 km). These techniques were being developed to create additional, disjunct populations of the whooping crane (G. americana). The cranes taught the migration route in 1995 did not follow the desired migration route in 1996 but did travel north 140 km along the route in …


Effects Of An Early Spring Burn On Greater Sandhill Crane Nesting Success At Malheur National Wildlife Refuge, Oregon, Carroll D. Littlefield, John E. Cornely, Bradley D. Ehlers Jan 2001

Effects Of An Early Spring Burn On Greater Sandhill Crane Nesting Success At Malheur National Wildlife Refuge, Oregon, Carroll D. Littlefield, John E. Cornely, Bradley D. Ehlers

Proceedings of the North American Crane Workshop

A 2430 ha prescribed burn was conducted on Malheur National Wildlife Refuge, Harney County, Oregon in March 1985. About 35 days later, 11 greater sandhill crane (Grus canadensis tabida) pairs nested within the burned area; 9 of these hatched. The remaining 2 clutches were destroyed by coyotes (Canis latrans). Crane hatching success was significantly higher (P = 0.01) on the burned area (81.8%) than elsewhere (38.5%). Two factors were likely responsible for the higher success rate in the burn; nests were placed in deeper water and the smaI1 mammal prey base was temporarily reduced or eliminated …


Models For The Adaptive Harvest Management Of Rocky Mountain Sandhill Cranes: Problems And Potential, William L. Kendall, Roderick C. Drewien Jan 2001

Models For The Adaptive Harvest Management Of Rocky Mountain Sandhill Cranes: Problems And Potential, William L. Kendall, Roderick C. Drewien

Proceedings of the North American Crane Workshop

The migratory Rocky Mountain Population (RMP) of the greater sandhill crane (Grus canadensis tabida) breeds primarily in river valleys, marshes, and meadows of western Montana and Wyoming, southeastern Idaho, northern Utah, and northwestern Colorado. The RMP winters primarily in the Middle Rio Grande Valley of New Mexico, with smaller concentrations in the southwestern parts of that state, southeastern Arizona, and the northern highlands of Mexico. The San Luis Valley of Colorado is used as a stopover in both the spring and fall migrations. The RMP has been hunted on a permit basis since 1981, and currently these cranes …


Nesting Ecology Of Sandhill Cranes At Grays Lake, Idaho, Jane E. Austin, L. J. Ball, Adonia R. Henry Jan 2001

Nesting Ecology Of Sandhill Cranes At Grays Lake, Idaho, Jane E. Austin, L. J. Ball, Adonia R. Henry

Proceedings of the North American Crane Workshop

We examined the nesting ecology of greater sandhill cranes (Grus canadensis tabida) at Grays Lake, Idaho during 1997-99 to detennine the effects of nest-site characteristics and land use on crane nest success. These are preliminary results from 3 years of a 4-year study. Crane nests were located in portions of the Grays Lake basin from early May through late June each year (n = 131 in 1997; n = 131 in 1998; n = 143 in 1999). Apparent nest success varied among years (54% in 1997, 71% in 1998, and 53% in 1999; overall average of 59%). We …