Minnesota study documents birds of high conservation priority associated with young forests

Young forests provide important nesting habitat for breeding birds and, once young birds leave the nest, many use young forests for food and cover. However, because of changes in natural and human disturbances of forests, the extent of young forest in much of eastern North America has recently declined. This has caused many scientists to identify conservation of bird species associated with young forests as a high priority.

Recently, the University of Minnesota Duluth, UPM-Blandin, Potlatch Corporation, and NCASI have been collaborating on a study of songbird response to forest harvesting in the Lake States. Principal investigators are Dr. Alexis Grinde and Dr. Gerald Niemi of the university’s Natural Resources Research Institute in Duluth.

The study is seeking to document changes over time in breeding bird communities in response to forest harvesting and contrast the use of young and mature forests during the post-breeding season by bird species that nest in mature and young forests. 

The study is being conducted in several large blocks (approximately 1 square mile each) of forest in which birds were sampled during the mid-1990s prior to extensive forest harvesting in 2001. Currently, the large forest plots consist of young forest intermixed with a variety of other forest age classes. Much of the field work to date has focused on a large forest block owned by UPM-Blandin, but sampling is now expanding to include other similar blocks.

As expected, preliminary results from the ongoing study indicate that the proportion of individual birds associated with young forests has increased in the large UPM-Blandin forest block since the mid-1990s.

An unanticipated finding, however, is that the large forest block has relatively high abundances for five species identified by Minnesota Audubon as “Stewardship Birds of Minnesota” including the Chestnut-sided Warbler, Golden-winged Warbler, Nashville Warbler, Rose-breasted Grosbeak, and Veery. 

Stewardship Birds are those for which 1) Minnesota contains 5% or more of the bird’s global breeding population, and 2) Minnesota encompasses 5% or more of their breeding range. Of the 314 bird species that regularly inhabit Minnesota, only 12 species meet these criteria. 

Overall, results from the study suggest that a complex forest landscape composed of a variety of age classes with “soft edges” between stands (where vegetation does not change abruptly) is beneficial for many forest bird species including birds of high conservation priority.

  

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