Wetlands of the sub-arctic and arctic are an important spring food source for migrating Lesser Snow and Ross’s geese. After leaving the Canadian prairies in May, geese cross the boreal forest and gather in large numbers along a narrow strip of coastal habitat, where vegetation is exposed earliest in spring. Geese obtain most of their fat reserves on grain fields in southern Canada, but most of their spring protein reserves come from below ground portions of grasses and sedges. Protein reserves are required for development of eggs and testes, and for normal energy demands during nesting, when little feeding takes place. For these reasons, the amount of spring protein reserves affects breeding success, and the number of goslings on the land in August.
As the number of Lesser Snow and Ross’s geese has increased across the arctic, spring feeding has damaged or changed coastal habitat, and because spring food is only available in snow-free areas, the amount of food available to each goose has decreased over time. It is important to understand the factors that determine how many geese the land can support, and so we are interested in how protein reserves in geese has changed though time. Since 2012, we have worked with local hunters in Churchill, Manitoba to obtain geese shot throughout the spring migration. By weighing and measuring different parts of the geese, we can see how protein reserves change through the spring, and compare this to the past. We found that Lesser Snow geese near Churchill have 14-20% less protein than in the 1970s, and do not gain any protein during this period, like they used to. On the other hand, the smaller Ross’s geese, which have expanded across the eastern arctic in the last few decades, are able to store protein at the same rate Lesser Snow geese did in the 1970s (8% over 2 weeks), and have similar protein levels to the most recent estimates from the early 2000s.
Our results from Churchill, Manitoba suggest that Lesser Snow geese nesting in the sub-arctic have lost the equivalent of about 3 eggs worth of protein since the 1970s, but many geese migrating through Churchill are returning to colonies much farther north, along western Hudson Bay, and on Southampton and Baffin Island. We would like to work with the Hunters and Trappers Organizaton (HTO) in Arviat, Coral Harbour, and Cape Dorset to obtain geese in spring, so we can learn how protein reserves change as birds travel northward, and if these birds are able to make-up some of these reserves as they approach northern breeding colonies.
In 2019-2020, with support from POLAR, and through the HTO we intend to work with community-based monitors towards collection of adult Lesser Snow (n=120) and Ross’s geese (n=120) prior to nesting. The community-based monitors will be responsible for collecting, labelling, and freezing geese, and then shipping them south. Once samples have been analyzed, biologists will travel to communities to report findings from this community-based monitoring effort.Individuals of each species will be harvested by members of communities during spring migration (prior to nesting).
The HTO will source individuals in the community interested in participating in this project, and through POLAR funding, individuals will be compensated for ammunition, equipment, gasoline, food, and transportation. Collectors will be instructed to randomly pass shoot adult birds at staging areas using shotguns and non-toxic ammunition. Birds will be bagged, labelled according to date, location, and species, frozen, and shipped south for measuring and dissection. Muscles will be excised, and superficial fat will be removed from muscles. Tibiotarsal and pectoral muscles (bone-free) will be weighed to produce an index of protein, which will be corrected for structural size. Abdominal fat will be removed and weighed to serve as a lipid index. Testes, ovary, and liver will be removed and weighed. Following dissection, a variety of statistical models will be developed to assess specific biological hypotheses.