Geology topics
D.R. Bystrak
Publications and source records attributed to D.R. Bystrak.
Bird population trends detected by the North American breeding bird survey
Continental populations of most bird species have remained quite stable since 1966, but there have been many regional changes associated with migration disasters, breeding failures and range expansions, and a few dramatic increases in populations of introduced species. These changes often are better represented by curvilinear than by linear regressions.
Polish Ecological Studies↗
Willow flycatcher breeding on the coastal plain of Maryland
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Maryland Birdlife↗
The seventy-fourth Christmas bird count. [Untitled. Summary for Delaware, Maryland, District of Columbia, and Virginia]
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American Birds↗
Late fall departure of slate-colored junco from Maryland
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Maryland Birdlife↗
23rd annual nest card summary, 1971
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Maryland Birdlife↗
Winter bird survey, 1972
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Maryland Birdlife↗