Upland nesting of American bitterns, marsh hawks, and short-eared owls. Prairie Naturalist 9:33–39

• Main Authors: Harold F Duebbert, John T Lokemoen
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1977
• Subjects: Circus cyaneus
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1061.6751; http://www.avibirds.com/pdf/N/Noordamerikaanse%20Roerdomp4.pdf

Nests of American bitterns lentiginosus) marsh hawks (Circus cyaneus), and short-eared owls (Asio u ually found in wetland habitats. Although large marshes containing dense stands of bulrushes (Scirpus), (Typha) , or other wetland vegetation are favored nesting cover , these birds have also been reported to nest in stands of tall , dense shrubs and grasses on the upland general observations in North Dakota over the past 20 years also suggest an alarmin g decrease in populations of these birds during the breeding season. We believe that these population declines may be correlated with the widespread destruction or degradation of essential nesting habitats as agriculture has become increasingly more intensive. DESCRIPTION OF COVER Nesting cover on the fields as reported by Duebbert and Lokemoen (1976), was composed of introduced cool-season grasses and legumes, primarily smooth bromegrass (Bromus intermediate wheatgrass termedium ), tall wheatgrass (A. elongatum) , alfalfa (Medicago sativa), and sweet clover (Melitotus spp.). Age of cover ranged from 2 to 8 years and the vegetation was in robust early stages. The cover was not hayed , razed, burned, or tilled and its structure was tall and dense with an abundance of standing stems, intermixed with lodged and flattened residual vegetation METHODS We located nests by flushing laying or incubating birds with a 53 m cable chain device towed between two et al. 1969). One to three com 33