The latest issue of The Wildlife Society’s magazine, The Wildlife Professional, features KBO Research Biologist Sarah Rockwell as its cover girl! The article mentions findings from Dr. Rockwell’s research on one of North America’s rarest songbirds – the Kirtland’s Warbler – conducted when she was a doctoral student at the University of Maryland and Smithsonian Migratory Bird Center. It details the story of the recovery of this species from 200 pairs in the 1970s-1980s to over 2,300 today. The article also discusses more recent research efforts to determine the Kirtland’s Warbler’s migratory routes and overwinter habitats, and evaluate whether continued Brown-headed Cowbird control is necessary.
When the Endangered Species Act was passed into law in 1973, the Kirtland’s Warbler was on the initial list of endangered and threatened species. The next challenge facing the Kirtland’s Warbler Conservation Team is to ensure ongoing habitat protection for this conservation-reliant species. This species has been recently proposed for removal from the endangered species list because of successful progress towards population recovery, and the U.S. Fish and Wildlife Service will make a decision in 2019.
Klamath Bird Observatory research scientist Dr. Sarah Rockwell was mentioned in the most recent issue of Living Bird, published by the Cornell Lab of Ornithology (click here to see the article). Sarah completed her Ph.D. research with Dr. Peter Marra (now Director of the Smithsonian Migratory Bird Center) on the endangered Kirtland’s Warbler in her home state of Michigan. She found that after drier winters in The Bahamas (which are predicted by several climate change models), Kirtland’s Warblers arrived on Michigan breeding grounds later in the spring, raised fewer offspring, and had lower survival rates that year. This emphasizes the importance of winter habitats for migratory birds; conditions there can carry over to affect birds during different parts of the annual cycle.
“Without natural wildfires, the Kirtland’s Warbler may always be a conservation-reliant species, but it is important to demonstrate the success the Kirtland’s recovery team has had in alleviating limitations on the breeding grounds, and increasing the population from around 200 pairs in the 1970s to over 2,000 pairs today,” says Sarah. “My research helped demonstrate threats that could result from drought on wintering grounds in The Bahamas, which still need to be addressed. Nathan Cooper’s research (discussed in the article) adds important data to the question of identifying where else Kirtland’s Warblers might be spending the winter, as well as important stopover sites along migratory routes, which would be good candidates for habitat protection. My work also demonstrated that Kirtland’s Warblers have higher mortality during migration than any part of the year, making this a critical part of its life cycle.”
Dr. Rockwell, who says she’ll always have a soft spot for this charismatic species, will present her research as an invited speaker in the Kirtland’s Warbler symposium that will take place as part of this year’s American Ornithological Society meeting. She will also present KBO research using birds as indicators to evaluate riparian restoration at beaver dam analogue sites in the Scott Valley, California (click here for more information about this project).
Dr. Sarah Rockwell’s Kirtland Warbler publications: Rockwell, S. M., C. I. Bocetti, and P. P. Marra (2012). Carry-over effects of winter climate on spring arrival date and reproductive success in an endangered migratory bird, Kirtland’s Warbler (Setophaga kirtlandii). The Auk 129:744-752. http://www.bioone.org/doi/full/10.1525/auk.2012.12003
Rockwell, S. M., J. M. Wunderle, Jr., T. S. Sillett, C. I. Bocetti, D. N. Ewert, D. Currie, J. D. White, and P. P. Marra (2017). Seasonal survival estimation for a long-distance migratory bird and the influence of winter precipitation. Oecologia 183:715-726. https://link.springer.com/article/10.1007%2Fs00442-016-3788-x