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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, …
Aerial Survey Techniques For Breeding Whooping Cranes, Brian W. Johns
Aerial Survey Techniques For Breeding Whooping Cranes, Brian W. Johns
Proceedings of the North American Crane Workshop
Since the discovery of nesting whooping cranes in Wood Buffalo National Park, the Canadian Wildlife Service has conducted aerial surveys to monitor the population. Aerial survey techniques have varied over the years; however, they have generally followed the techniques used by the author since 1991. The technique involves flying a combination of circular flights and transects over known nesting territories and similar looking marshes likely to contain breeding whooping cranes. These aerial surveys account for nearly 100% of the breeding whooping cranes each year.