FORAGE QUALITY IN BROOD REARING AREAS OF THE LESSER SNOW GOOSE AND THE GROWTH OF CAPTIVE GOSLINGS

1. Experimental feeding trials using captive goslings of lesser snow geese were carried out on the breeding grounds at La Perouse Bay, Manitoba, in order to determine the birds' ability to utilize different forage types. 2. The birds were allowed to graze salt-marsh swards of either Puccinellia phryganodes or Carer subspathacea, and inland swards of Festuca rubra and Carex x flavicans. Duck chow and freshly chopped leaves of Carer aquatilis were provided in further trials. The experiments were fully replicated and birds feel for 6 hours. 3. Besides net changes in weight of birds, the following were measured: acid-detergent fibre, silica, nitrogen, and phosphorus and ash contents of forage tissues and faeces. Amounts of serveral inorganic cations and anions in these materials were also determined. 4. In general, the birds gained or maintained weight on the salt-marsh forages which had higher nutrient contents, and lower fibre and silica contents than the alternative species. The birds either maintained or lost weight when feeding either on inland swards or on Carer aquatilis. 5. These results support the field evidence that the decline in gosling weight over the last decade reported at La Perouse Bay is the result of a lack of preferred salt-marsh forage and the use of alternative species by the birds.