Timing of Nesting by Canada Geese in Relation to the Phenology and Availability of Their Food Plants
Timing of Nesting by Canada Geese in Relation to the Phenology and Availability of Their Food Plants
复制标题
加拿大鹅筑巢的时间与其食用植物的物候和可用性有关
DOI：
10.2307/4435
复制
发表时间：
1986
影响因子：
4.8
通讯作者：
D. G. Raveling
中科院分区：
文献类型：
--
作者：
J. S. Sedinger;D. G. Raveling
(1) This study examined seasonal variation in the foraging behaviour of cackling Canada geese (Branta canadensis minima) and in the nutrient content and availability of tundra grasses and sedges (graminoids) and arrowgrass during the nesting and brood-rearing periods, 1977-79 on the Yukon-Kuskokwim Delta, Alaska. (2) Nitrogen concentrations in nearly all graminoids and arrowgrass began to decline either prior to, or during, hatching of cackling goose clutches. Grazing or clipping of vegetation resulted in higher and prolonged peaks in nitrogen concentration but peak nitrogen levels in these plants still occurred within a week of the end of the hatching period. (3) Standing crops of graminoids increased until early August while the standing crop of arrowgrass (the most nutritious plant in the diet) in preferred foraging habitat began to decline in mid-July due to grazing by geese. (4) Peck-rates of adult cackling geese tended to decline as brood-rearing progressed, indicating that preferred foods declined in availability during this period. Also, late in brood-rearing, preferred foraging areas were used less and arrowgrass comprised a smaller proportion of the diet. (5) Changes in plant nutrient levels and shifts in diet and habitat use reduced the nutritional quality of the diet as brood-rearing progressed. Thus, as a result of both the natural phenology of tundra plants and grazing by geese, late hatching broods were at a nutritional disadvantage compared to those hatching early. (6) We conclude that a seasonal decline in the quality of foraging conditions is probably an important factor favouring early nesting by geese.
