PSU Professor, Students Collaborate on Canada Warbler Research

March 27th, 2006 by Adam

For the fourth consecutive spring, PSU biology chair Dr. Len Reitsma and his colleagues will brave the black flies and mosquitoes in Canaan, N.H., to band, track and study the diminishing Canada warbler, a small black, yellow and slate-colored bird that has been disappearing from the state due to loss of habitat. Reitsma and undergraduate and graduate students from PSU, Louisiana State University and Salve Regina University have collaborated with conservation biologist Dan Lambert, formerly of the Vermont Institute of Natural Science, to produce research they hope will help preserve this species.

As a result of the research, Lambert and Steve Faccio of the Vermont Institute of Natural Science have produced a brochure aimed at promoting and sustaining Canada warbler breeding populations. The publication lists stewardship guidelines for land managers, homeowners and conservationists that focus on the preservation of young forest stands, mixed forest areas and swampy areas where warblers like to nest.

Lambert now works for the American Bird Conservancy as Northeast bird monitoring coordinator. He sees a continuing need for research on the Canada warbler, particularly research focused on habitat threats and environmental contaminants such as mercury, which has been shown to alter behavior, reduce breeding success and shorten life spans in northeastern water birds. Because the warbler resides in a variety of habitats, from mixed forest to swamps and timber harvest zones, it is important to study and compare each of these areas in order to determine which conservation practices will best help the species.

“As a conservation biologist, I’m most interested in learning about stewardship practices that help conserve this uncommon and declining species. Understanding differences in the quality of its various habitat types is key to protecting the species,” said Lambert.

In order to study the warbler’s habitat preferences and breeding ecology, Reitsma, Lambert and other researchers capture birds and place colored bands on their legs. After releasing the birds, the researchers map their travels using GPS units and characterize their individual territories using standard vegetation measurements. Researchers are able to gain a clear understanding of the habitat preferences of Canada warblers by comparing these vegetation measurements to those of adjacent unoccupied habitat.

One of the more remarkable findings of this study, according to Reitsma, is the fact that about half of the banded birds in the study return each season to the exact same location in New Hampshire. Canada warblers are Neotropical-Nearctic migrants, spending winters in the forested eastern slopes of the Andes Mountains south of Columbia, and traveling over 4,000 miles each year to and from breeding grounds in the northeast.

Mike Hallworth, a PSU graduate student who has participated in the Canada warbler research for the past two years, also finds the bird’s migration patterns remarkable. He is making the warbler’s breeding ecology the focus of his master’s thesis project, and hopes someday to travel to South America to observe the bird in its winter habitat.

“The Canada warbler is an amazing species, and it’s a species that not much work has been done on,” says Hallworth, who is working toward his M.S. in Environmental Science and Policy. “I find it fascinating that a bird that weighs only 10 grams migrates from central New Hampshire to the eastern slope of the Andes twice a year. I also find it fascinating that the males come back to the exact same location, within meters of their previous year’s territory,”

During his field studies, Hallworth has also been looking at the phenomenon of extra pair copulation, which occurs when there is more than one male parent represented in a single nest. Hallworth takes a small sample of blood from parent birds and nestlings to complete this research, which has not previously been undertaken for this species.

Reitsma, Hallworth and other researchers have also been comparing age ratios and breeding successes of male birds in two different habitats, a red maple swamp and a heavily cut, 25-year-old forest, in hopes of making management recommendations for the warbler.

“We can’t wait to get back into the field this spring and face the biting flies to see who has returned again to breed,” said Reitsma.

Plymouth State University (PSU) is a regional comprehensive university offering a rich, student-focused learning environment for both undergraduate and graduate students. PSU offers 42 majors and 62 minors in programs that include education, business, humanities, arts, and natural and social sciences. The College of Graduate Studies offers coursework that promotes research, best practices and reflection in locations on- and off-campus as well as online. For non-traditional students, PSU’s Frost School of Continuing and Professional Studies offers working professionals opportunities to pursue an undergraduate degree by attending classes in the evenings, weekends and online. Located in a beautiful New England setting, Plymouth State University has been recognized as one of the “Best in the Northeast” by The Princeton Review.