Feeding Ecology of Trumpeter Swans Breeding in South Central Alaska
Grant TA, Henson P, Cooper JA. 1994. Feeding Ecology of Trumpeter Swans Breeding in South Central Alaska. The Journal of Wildlife Management. 58(4):774-780
Identification of important spring and summer foods for breeding adult trumpeter swans (Cygnus buccinator) and their young is critical to understanding factors that affect their use of habitat and breeding success. In 1988-89, we used activity time budgets to determine the spring and summer diet of trumpeter swans breeding on the Copper River Delta (CRD), Alaska. Adults fed predominantly on submerged aquatics before and during egg laying but shifted to emergent horsetail (Equisetum fluviatile and E. arvense) and sedge (Carex lyngbyaei) during incubation. Females spent less time feeding on submerged aquatics (P lt 0.07) and more time feeding on horsetail (P lt 0.03) than did males during incubation and post-hatch. Horsetail dominated post-hatch diets of adults and young. Cygnets dabbled more (P lt 0.01), spent more time feeding on horsetail (P lt 0.08), and spent less time feeding on submerged aquatics (P lt 0.03) than did adults. Aerial shoots of horsetail developed continuously from rhizomatous tips throughout the spring and summer, providing a source of protein for cygnet development and for replacement of tissues depleted during nesting and for flight feather development in adults.
- Type
- Journal Article
- Authors
- Grant, Todd; Henson, Paul; Cooper, James
- Units
- CAKN , DENA , WRST
- Keywords
- Carex lyngbyaei, Copper River Delta, Cygnus buccinator, Diets, Equisetum arvense, Equisetum fluviatile, Reproduction