The hand-written signature is one way people identify themselves. Animal signatures take different forms. Environment Canada researchers have developed a new chemical tool to help track the migration of monarch butterflies, birds, and other small migratory wildlife that are otherwise difficult to follow using conventional tag-recapture techniques.
Yellow warblers are migrant songbirds that breed in the north and winter in the south.
Several years ago, scientists at the Prairie and Northern Wildlife Research Centre and National Water Research Institute in Saskatoon were seeking new ways to link the breeding and wintering areas of migrant songbirds, whose populations were declining. The ability to assess the breeding origins of wintering migrants would be a powerful tool in their protection. Deuterium, a stable isotope of hydrogen, occurs naturally in rainwater across North America. The deuterium content of rain shows up in the tissues of shallow-rooted plants. Animals that feed on these plants incorporate this deuterium into their bodies.