Effect of a Spring Hunt on Nutrient Storage by Greater Snow Geese in Southern Quebec

Abstract

A spring conservation hunt (15 Apr-31 May) to control the exponential population growth of greater snow geese (Chen caerulescens atlantica) was introduced in 1999 during their staging in southern Quebec, Canada. We tested the hypothesis that disturbance by hunting negatively affected nutrient storage in spring. We compared the amount of fat and protein stored by staging geese during the hunt (1999 and 2000) to similar data obtained sporadically between 1979 and 1998 (no hunt). We collected adult females at 3 sites along the St. Lawrence River during years with (n = 235 geese) and without (n = 194) hunting. We used abdominal fat and dry breast muscle mass as corresponding indices of fat and protein reserves. The condition of geese arriving at the staging area did not differ between years with and without a hunt. Abdominal fat of geese at the end of the staging period was 29-48% lower (depending on site and year) during years with a hunt than in years without. Similarly, breast muscles of geese at the end of staging were 5-11% lighter in years with a spring hunt. Low stable-carbon isotope ratios (δ 13 C) in tissues of geese collected in spring 1999 suggested that they fed less on corn, a C4 plant and a major food source for geese, than in other years. This may have contributed to their reduced body condition that year. However, despite high δ 13 C values in 2000, indicative of a high proportion of corn in the diet, nutrient storage in geese was still reduced compared to years without a hunt. We conclude that hunting was the most important factor explaining the low fat and protein storage of geese in springs of 1999 and 2000. We suggest that hunting disturbance reduced nutrient storage of geese because of decreased feeding activity and increased flying time.