The canada geese involved in the Cactus 1549 incident were actually migratory. It is the resident ones that are problematic.

> The Smithsonian Institution also performed a stable-hydrogen isotope analysis of the feather material collected from the airplane engines and compared the results with feather samples collected from resident geese in the New York region. The results indicated that the feathers from the airplane engines were similar to samples of known migratory geese and were significantly different from year-round resident populations from the New York region.