Science in Minnesota, North Dakota and South Dakota

Studying Juncos at Whitney Preserve, South Dakota

The avian genus Junco is one of the most recently and rapidly diverging lineages of North American songbirds, making it an excellent model for comparative studies. The white-winged junco, a small, grey songbird in the sparrow family, is a sub-species of the dark-eyed Junco (J. hyemalis). It is unique in that it breeds only in the Black Hills, and is larger on average than other juncos, with more white on the tail and distinctive white bars on the wings, for which it was presumably named..

Conservancy preserves are important resources for our science staff as well as for researchers from other institutions. Graduate students from Indiana University spent the summer of 2007 at Whitney Preserve to study reproductive behavior of the white-winged junco—a unique bird that breeds only in the Black Hills.

The research of Dr. Ellen Ketterson of Indiana University led two of her graduate students, Christine Bergeon and Kristal Cain, to study this species. Dr. Ketterson has studied a population of juncos that breeds in the Appalachian mountains of Virginia for many years. During a trip to the Black Hills, she found the white-winged juncos to be plentiful and worthy of further study.

Bergeon and Cain are studying the effects of steroid hormones on the bird’s physiology, morphology and reproductive behavior. The researchers hope to find that hormone levels correlate with reproductive timing, as well as with certain morphological features in the individuals—such as the amount of white they have on their tails or wings—and if these things correlate with behaviors. For an idea of how much variation there is in the sub-species they worked in four different areas of the Black Hills.

“The research is especially exciting because little work has been done with these birds since Nathaniel Whitney (the Conservancy’s preserve namesake) reported on them in the 1960s,” said Cain.

Christine Bergeon taking blood sample from white-winged junco

In 2007 they captured, banded and took blood samples from almost 200 white-winged juncos. The bands give each bird a unique identity, so researchers could follow them throughout the breeding season and across several years. Blood samples are used for DNA assessments of paternity and hormone analysis.

Cain and Bergeon share similar research interests, although are interested in slightly different questions and goals. Bergeon is interested in reproductive timing: how the birds "know" precisely when it's time to reproduce based on various environmental cues such as day length, temperature or food availability. Cain’s research looks at what animals in different environments change in order to be successful at reproduction, and how differences in ecology lead to differences in the way the birds look and act. She is also examining how hormones that the mothers put in eggs affect their young.

Kristal Cain weighing a white-winged junco “Our research would not have been possible this summer without help from the Conservancy’s Whitney Preserve,” remarked Bergeon. “The guest house provided us with housing and facilities for our lab work, and the low density of birds on the preserve during this dry, hot summer suggested a limit to conditions suitable for junco breeding. Our interactions with other researchers and guests provided additional insights into many aspects of Black Hills ecology and conservation—and we discovered resources and connections that we hope to draw on in our next few field seasons for our Ph.D. dissertation research.”

We've had a wonderful summer and have loved working with the Conservancy on this project,” Cain said. “We both look forward to the next few years of continuing work.”

Photo credits (top to bottom, left to right): All photos © Kristal Cain. Male white-winged junco.
Two junco nestlings -- there is an obvious size difference because one always hatches a day later than the others. Christine Bergeon taking a blood sample from a junco, which is used for DNA and hormone analysis. Kristal Cain weighing a white-winged junco.