Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Publication Type
Articles 1 - 2 of 2
Full-Text Articles in Population Biology
Density And Abundance Of Secretive Marsh Birds In Iowa, Tyler Harms, Stephen Dinsmore
Density And Abundance Of Secretive Marsh Birds In Iowa, Tyler Harms, Stephen Dinsmore
Tyler Harms
A decrease in wetland habitats throughout North America has caused a decline in populations of marsh birds. The objective of this study was to estimate population densities and abundances of secretive marsh birds in Iowa. Call-broadcast surveys were conducted in conjunction with distance sampling for eight species of marsh birds at wetlands in three regions of Iowa during 2009 and 2010. Regions were defined by observed microhabitat characteristics which also corresponded to physiographic regions. Region-specific density estimates were obtained using Program Distance for four species of marsh birds for which sufficient detections existed (Pied-billed Grebe [Podilymbus podiceps], Least …
The Utility Of Census Or Survey For Monitoring Whooping Cranes In Winter, Bruce H. Pugesek, Thomas V. Stehn
The Utility Of Census Or Survey For Monitoring Whooping Cranes In Winter, Bruce H. Pugesek, Thomas V. Stehn
Proceedings of the North American Crane Workshop
We discuss recent changes in the monitoring program for endangered whooping cranes (Grus americana) on their winter habitat in Texas. A 61-year annual census was replaced in the winter of 2011-2012 with a distance sampling procedure. Justification for the change was, in part, based on criticism of the previous methods of counting cranes and the assessment of crane mortality on the wintering grounds. We argue here that the arguments, methods, and analyses employed to discount the census procedure and mortality estimates were applied incorrectly or with flawed logic and assertions. We provide analysis and logical arguments to show …