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Full-Text Articles in Population Biology
Global Warming And Population Responses Among Great Plains Birds, Paul A. Johnsgard
Global Warming And Population Responses Among Great Plains Birds, Paul A. Johnsgard
Zea E-Books Collection
Based on an analysis of 47 years (1967–2014) of Audubon Christmas Bird Counts (CBC), evidence for population changes and shifts in early winter (late December) ranges of nearly 150 species of birds in the Great Plains states is summarized, a region defined as including the Dakotas, Nebraska, Kansas, Oklahoma, and the Texas panhandle. The rationale for this study had its origins in Terry Root’s 1988 Atlas of North American Wintering Birds. Root’s landmark study provided a baseline for evaluating the nationwide winter distributions of 253 North American birds in the mid-20th century, using data from the National Audubon Society’s …
Wintering Sandhill Crane Distribution And Habitat Use Patterns At Bosque Del Apache National Wildlife Refuge, New Mexico, Tandi L. Perkins, Leigh H. Fredrickson
Wintering Sandhill Crane Distribution And Habitat Use Patterns At Bosque Del Apache National Wildlife Refuge, New Mexico, Tandi L. Perkins, Leigh H. Fredrickson
Proceedings of the North American Crane Workshop
The single most important factor regulating sandhill crane (Grus canadensis) populations is their ability to carry out annual life cycle events while responding to changing habitat availability and distribution across local, regional, and continental landscapes. Wetland and cropland resource availability and distribution across the landscape have become increasingly unpredictable. Recent changes in farming practices, urbanization, and prevailing drought conditions in New Mexico have transformed and reduced dynamic, heterogeneous landscapes into scattered fragments of the original setting. Concerns are increasing for the cumulative influence of these often irreversible actions in providing the type of resources needed by cranes at …
Preliminary Wintering Counts And New Locations Of Sandhill Cranes In Mexico, Ingrid Barceló, Edgar G. López, Felipe Chávez-Ramírez
Preliminary Wintering Counts And New Locations Of Sandhill Cranes In Mexico, Ingrid Barceló, Edgar G. López, Felipe Chávez-Ramírez
Proceedings of the North American Crane Workshop
Sandhill cranes (Grus canadensis) undertake a migration twice a year, when more than 400,000 cranes cross the United States from the Arctic of North America and Eastern Siberia to the southwest U.S. and north central Mexico. Although the sandhill crane has been studied intensely, few studies have been done on their Mexican wintering grounds. Little is known about what proportion of the sandhill crane population migrates to Mexico, and there is even less information regarding its dispersion. During winter 2007-2008 we surveyed 30 wetlands in the Chihuahuan Desert ecoregion in northern Mexico, recording presence/absence and number of sandhill …
Food And Energy Intake Rates Of Wintering Whooping Cranes Foraging On Two Selected Food Items, Felipe Chavez-Ramirez, Jay T. Nelson, R. Douglas Slack
Food And Energy Intake Rates Of Wintering Whooping Cranes Foraging On Two Selected Food Items, Felipe Chavez-Ramirez, Jay T. Nelson, R. Douglas Slack
Proceedings of the North American Crane Workshop
Number, mass, and potential energy of food items consumed by wintering whooping cranes (Grus americana) foraging on blue crab (Callinectes sapidus) and woltberry (Lycium carolinianum) fruit were estimated and compared between 2 consecutive winter periods. Mass consumed was determined through field observations by quantifying the number of items taken per unit time and the average, or modal, weight of each food item determined from collections. Gross energy intake was determined by calculating the product of mass consumed times gross energy (kJ/g) of each food item. Potential energy retained was calculated by determining metabolizable energy …
Sandhill Cranes In The Mid·Pecos Valley Of Eastern New Mexico, 1989- 91, James B. Montgomery
Sandhill Cranes In The Mid·Pecos Valley Of Eastern New Mexico, 1989- 91, James B. Montgomery
Proceedings of the North American Crane Workshop
Weekly roost counts and observations of flock movements and field use were conducted during winters of 1989 -90 and 1990-91 to determine the status of sandhill cranes (Grus canadensis) in the RoswelllBitter Lake National Wildlife Refuge region of the Pecos River Valley of eastern New Mexico. Cranes roost on shallow lakes along the Pecos River, both on and off the refuge, and rely on approximately 36,000 ha of mostly irrigated farmland for foraging. During the past decade, alfalfa production has increased to 20,000 ha and corn production has decreased to 2,000 ha, of which 98 % is cut …
Whooping Crane Response To Disturbances At The Aransas National Wildlife Refuge, Thomas E. Lewis, R. Douglas Slack
Whooping Crane Response To Disturbances At The Aransas National Wildlife Refuge, Thomas E. Lewis, R. Douglas Slack
Proceedings of the North American Crane Workshop
Many forms of disturbance on and near the Aransas National Wildlife Refuge cause disruptions to wintering whooping cranes (Grus americana). Known forms of disturbance include various boating, aircraft, and automobile traffic. Natural disturbance from other wildlife also occurs. Behavioral observations and disturbance documentation have shown that Whooping cranes respond differently to various disturbances. Although airplane overflights, recreational boating, barge traffic. and workboat activity represent the most frequent disturbances to whooping cranes (22, 19, 14, and 13 %, respectively, of total disturbances), it appears that frequency of occurrence is less important than the disturbance class and distance from the …