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Full-Text Articles in Life Sciences
Countability Of Sandhill Cranes In Aerial Surveys, Douglas H. Johnson, John W. Solberg, Courtney L. Amundson
Countability Of Sandhill Cranes In Aerial Surveys, Douglas H. Johnson, John W. Solberg, Courtney L. Amundson
Proceedings of the North American Crane Workshop
Aerial surveys are used to monitor populations of many wildlife species, including sandhill cranes (Grus canadensis). In addition to the usual problems of detectability (involving both availability and perceptibility), aerial surveys of concentrated animals are subject to countability issues; from a rapidly moving aircraft, observers cannot count or accurately estimate the number of animals in a large group. Calibration is sometimes performed in an effort to adjust aerial counts for incomplete detectability and countability by calculating the ratio of animals actually in a group to the number in the group estimated from the aircraft. Here we explore alternative, …
Whooping Crane Migrational Habitat Use Of The Platte River, Nebraska, 2001-2006, Shay Howlin, Clayton Derby, Dale Strickland
Whooping Crane Migrational Habitat Use Of The Platte River, Nebraska, 2001-2006, Shay Howlin, Clayton Derby, Dale Strickland
Proceedings of the North American Crane Workshop
The Platte River Endangered Species Partnership monitored whooping crane (Grus americana) habitat use along the Platte River between Chapman and Lexington, Nebraska during 11 migration seasons from 2001 to 2006. Daily aerial surveys took place in the morning from 21 March to 29 April in the spring and from 9 October to 10 November in the fall. Decoy detection trials were conducted during each of the 11 survey seasons to calculate actual sample inclusion probabilities for crane groups detected during monitoring flights. The detectability model found significant differences in detectability among strata (upland or channel), contractor, and altitude …
Sandhill Crane Staging And Whooping Crane Migratory Stopover Dynamics In Response To River Management Activities On The Central Platte River, Nebraska, Usa, Felipe Chavez-Ramirez
Sandhill Crane Staging And Whooping Crane Migratory Stopover Dynamics In Response To River Management Activities On The Central Platte River, Nebraska, Usa, Felipe Chavez-Ramirez
Proceedings of the North American Crane Workshop
The Central Platte River Valley (CPRV) is a critical stopover for migrating whooping cranes (Grus americana) and the most important staging area for sandhill cranes (G. canadensis) in North America. Due to reduced water flows caused by human activities, the Platte River no longer follows its traditional hydrograph which consisted of high spring flows that produced scouring action that eliminated vegetation. To provide adequate crane roosting habitat during stopover and staging periods, annual and woody vegetation has been mechanically cleared on eastern portions of the CPRV since 1980. Staging sandhill crane riverine roosting area has decreased …