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Full-Text Articles in Ornithology
Factors Influencing Greater Sandhill Crane Nest Success At Malheur National Wildlife Refuge, Oregon, Gary L. Ivey, Bruce D. Dugger
Factors Influencing Greater Sandhill Crane Nest Success At Malheur National Wildlife Refuge, Oregon, Gary L. Ivey, Bruce D. Dugger
Proceedings of the North American Crane Workshop
We used logistic regression to model the effects of weather, habitat, and management variables on Greater Sandhill Crane (Grus canadensis tabida) nest success at Malheur National Wildlife Refuge in southeast Oregon. We monitored 506 nests over 9 breeding seasons. Mean apparent nest success was 72% ± 4% and varied from 51 to 87%. Nest success was lower one year after a field was burned and declined with nest initiation date. Nest success was higher during warmer springs, in deeper water, and in years with moderate precipitation. Haying, livestock grazing, and predator control did not influence nest success. We …
Impact Of Management Changes At An Autumn Greater Sandhill Crane Staging Area In Oregon, Carrol D. Littlefield
Impact Of Management Changes At An Autumn Greater Sandhill Crane Staging Area In Oregon, Carrol D. Littlefield
Proceedings of the North American Crane Workshop
Malheur National Wildlife Refuge, Oregon was the most important autumn staging area for greater sandhill cranes (Grus canadensis tabida) in the northwest Pacific coastal states. During 1983-88, changes in management including increases in human disturbance and habitat alterations resulted in significant declines in autumn crane use. Compared with the period 1975-82, mean annual autumn crane peak numbers declined from 2,454 to 1,352, whereas mean biweekly numbers declined from 791 to 353. Management changes included roost site drying and flooding of a primary feeding area; disturbance factors included cattle herding through a loafing site and dump trucks traveling through …
Annual Movements Of Pacific Coast Sandhill Cranes, Gary L. Ivey, Caroline P. Herziger, Thomas J. Hoffmann
Annual Movements Of Pacific Coast Sandhill Cranes, Gary L. Ivey, Caroline P. Herziger, Thomas J. Hoffmann
Proceedings of the North American Crane Workshop
The subspecies composition of migratory sandhill cranes (Grus canadensis) which stage and winter along the Lower Columbia River in northwest Oregon and southwest Washington is uncertain, but may include all 3 using the Pacific Flyway: lesser (G. c. canadensis), Canadian (G. c. rowani), and greater (G. c. tabida). However, the status of rowani has been debated. During 2001-02, we captured and marked 8 cranes using a noose line trapping technique, and attached Platform Transmitter Terminals (PTTs) to 6 to ascertain locations of their breeding areas, migration corridors and winter sites. Morphometric data …
Using Ivermectin To Increase Survival Of Sandhill Crane Colts At Malheur National Wildlife Refuge, Oregon, Gary L. Ivey, Caroline P. Herziger
Using Ivermectin To Increase Survival Of Sandhill Crane Colts At Malheur National Wildlife Refuge, Oregon, Gary L. Ivey, Caroline P. Herziger
Proceedings of the North American Crane Workshop
Parasitic gapeworms (Cyathostoma sp.) caused 5.6% of mortalities of219 radiomarked greater sandhill crane (Grus canadensis tabida) colts at Malheur National Wildlife Refuge (NWR) in Oregon from 1991-98. From 1993-98 we tested the efficacy of ivennectin, an antihelmenthic drug, as a means of increasing colt survival by reducing gapewonn infestations. We selected pairs of siblings for the study, injecting 1 colt with ivennectin and not the other. We found significantly shorter survival times for untreated birds compared to those treated with ivennectin (P = 0.06). We conclude that in areas with gapewonn infestations in young cranes, the …
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
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 …
Mortality Of Radio-Equipped Sandhill Crane Colts At Malheur National Wildlife Refuge, Oregon, Gary L. Ivey, Eric J. Scheuering
Mortality Of Radio-Equipped Sandhill Crane Colts At Malheur National Wildlife Refuge, Oregon, Gary L. Ivey, Eric J. Scheuering
Proceedings of the North American Crane Workshop
We radio-equipped 142 greater sandhill crane (Grus canadensis tabida) colts at Malheur National Wildlife Refuge, Oregon, during 1991-95 to document prefledging mortality factors. Fates of 19 colts were undetermined. A total of 23 colts survived to fledge (19% of known fates). Evidence collected from the carcasses and death sites indicated that predators were responsible for the largest number of colt deaths (64), followed by unknown causes (13), parasitic gapeworms (Cyastoma spp.) (8), drowning (7), intraspecific aggression (5), study-related mortality (I), roadkill (I), and hay swather (1). Of 64 colts killed by predators, 26 were lost to mink …
Nesting Success And Production Of Greater Sandhill Cranes During Experimental Predator Control At Malheur National Wildlife Refuge, Oregon,1982-83, Carroll D. Littlefield, John E. Cornely
Nesting Success And Production Of Greater Sandhill Cranes During Experimental Predator Control At Malheur National Wildlife Refuge, Oregon,1982-83, Carroll D. Littlefield, John E. Cornely
Proceedings of the North American Crane Workshop
Greater sancfrtill cranes (Grus canadensis tabida) nest commonly on Malheur National Wildlife Refuge, Oregon, but depredations by common ravens (Corvus corax) and coyotes (Canis latrans) contributed substantially to low recruitment during the 1970's. An experimental predator removal study was initiated in 1982 to determine if nesting success and recruitment would increase if predator populations were reduced. We monitored 120 crane nests located in 2 treatment areas (ravens and coyotes removed, and only ravens removed) and 1 control area (40 nests per area). Nesting success between the 2 predator control areas differed significantly during the …