People are fascinated by disasters, and one that did not happen made news around the world. It was the landing of US Airways flight 1549 in the Hudson River on January 15, 2009. The cause of the crash was that shortly after takeoff, the plane hit a flock of what proved to be Canada geese that destroyed the engines. Remains of bird strikes in the United States are generally sent to the Ornithology Department at the Smithsonian Institution for identification using feathers and DNA sequences. These techniques identify the species, but a friend and colleague, Dr. Peter Marra from the Smithsonian’s Migratory Bird Center wanted to determine if these birds were local Canada geese from the New York area or migratory geese spending the winter in the New York region, something these techniques could not determine.
How do you figure this out? Pete called us with an idea. He had access to feathers from the birds that hit the plane; he also had feathers of local non-migratory birds that stay year-round in the New York area. He wanted to analyze the stable isotopes in these feathers. Isotopes are naturally occurring variants of elements, and in the case of hydrogen, there is documented geographic variation associated with latitude. Pete thought a study of the isotopes in goose feathers comparing those from the plane crash with migratory and non-migratory birds might answer the question. He had previously used isotopes in his research on migratory warblers to document aspects of their migration patterns.
Dr. Marra contacted The Field Museum’s Bird Division because he knew we had recently taken on a truly amazing collection of Canada geese made by wildfowl biologist Harold Hanson. This collection of series of Canada geese from throughout their breeding and wintering range was the subject of Hanson’s life work on geographic variation in this widespread species. Hanson’s two-volume tome on this collection (Hanson 2006, 2007) was published posthumously by his colleague Bert Anderson and the Illinois Natural History Survey. Included in the collection were small series of birds from the breeding season in Newfoundland and Labrador, the breeding areas of birds that winter in New York. Dave Willard, our collections manager, plucked several feathers of the birds and mailed them to Washington to be included in the isotope study.
The results were published in the following paper:
Marra, Peter P., Dove, C. J., Dolbeer, R., Dahlan, N. F., Heacker, M., Whatton, J. F., Diggs, N. E., France, C. and Henkes, G. A. 2009. Migratory Canada geese cause crash of US Airways Flight 1549. Frontiers in Ecology and the Environment, 7(6): 297-301.
The birds that hit the plane had an hydrogen isotope pattern similar to Hanson’s birds from Labrador in the far northern part of the range, and thus they probably bred or were born there and migrated south (although several New York area biologists have pointed out that “resident” New York birds have been known to fly north just to molt when their nests fail). This information may indicate that the real problem for airports is not resident birds that may learn about airplane flight paths, but naive migrants wintering in the region.
One might guess that Harold Hanson could have had no idea his specimens might be used in such a state-of-the-art analysis to solve such a question when he traveled to the northern reaches of the Canadian Arctic to collect these specimens more than 40 years ago, but Hanson studied all aspects of goose biology including analyzing mineral content of feathers to figure out where wintering birds had bred. He might not have been surprised at all.
Hanson’s collection came to The Field Museum because of concerns about its long-term care, and we are looking for funding to purchase much-needed new cases for this special collection that includes study skins, as well as trunk skeletons, gizzard contents, and other valuable natural history data. Now that the collection is up in the third floor of The Field Museum, it is being databased and made accessible to those wishing to answer all manner of questions about Canada geese far into the future. We always emphasize to anyone visiting our collections that you never know what our specimens may be used for through time, but because they represent a unique comprehensive sampling of so many bird species, they will be used.
Hanson, H. C. 2006. The White-cheeked Geese: Taxonomy, ecophysiographic relationships, biogeography, evolutionary considerations. Vol. 1. 420 pp. Illinois Natural History Survey. Champaign, IL.
Hanson, H. C. 2007. The White-cheeked Geese: Taxonomy, ecophysiographic relationships, biogeography, evolutionary considerations. Vol. 2. 692 pp. Illinois Natural History Survey. Champaign, IL