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Emperor Goose Life History

Habitat

Marshes

Emperor Geese nest in a relatively small area in Alaska, in saltmarsh habitats of the Yukon-Kuskokwim Delta. This vast area of wetlands provides habitat for millions of migrating, staging, and nesting birds, especially waterfowl and shorebirds. Its brackish rivers, sloughs, mudflats, and lakes support plants such as creeping alkaligrass, Mackenzie’s sedge, Hoppner’s sedge, Ramensk’s sedge, marsh arrowgrass, Fisher’s tundragrass, and circumpolar reedgrass. These plants provide food for Emperor Geese close to their nesting habitat. The birds nest within short vegetation along riverbanks, sloughs, and other shorelines, on islands and peninsulas, or near hummocks in the marsh or tundra. Plants in nesting areas may include dwarf shrubs such as willows, black crowberry, and other plants in the blueberry genus (Vaccinium). During migration, Emperor Geese use lagoons and other tidal areas of the northern Alaska Peninsula, where blue lyme grass predominates. Wintering Emperor Geese also favor ice-free marine habitats where eelgrass and sea lettuce can be abundant. Unlike some geese, which leave their foraging areas to roost, Emperor Geese generally stay very near the beach when roosting, though they move up onto adjacent higher ground.

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Food

Plants

Emperor Geese eat mostly marine invertebrates and plant matter. They forage for mussels and barnacles in shallow water, tipping up to grasp (or pry) them from rocks or from the sea floor. When feeding on plants, they graze on shoots (and dig out roots) of grasses and sedges much like other geese; they also pluck ripe berries. Common prey items include Baltic clam, blue mussel, and barnacles. Emperor Geese consume a wide variety of tundra and marsh plants, including creeping alkaligrass, marsh arrowgrass, beach rye, blue lyme grass, beach pea, seabeach sandwort, Fisher’s tundragrass, Hoppner’s sedge and other sedges, black crowberries, eelgrass, and marine algae such as sea lettuce.

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Nesting

Nest Placement

Ground

The female selects the nest site, with male following her, usually in fairly tall, dead vegetation near a landscape feature such as the edge of a river or pond or a rise in the tundra.

Nest Description

The female builds the nest, first making several scrapes, then laying the first egg in the preferred scrape, then continuing to build the nest as she lays more eggs. Nests incorporate her own down feathers and vegetation from the area around the nest scrape. Nests average about 14.8 inches across, with interior cup about 7.8 inches across and 3.2 inches deep.

Nesting Facts

Clutch Size:3-5 eggs
Number of Broods:1 brood
Incubation Period:24-25 days
Egg Description:

Creamy white or dull white.

Condition at Hatching:

Downy and ready to leave the nest in 1–6 hours. Chicks weigh 2.5 to 3 ounces at hatching.

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Behavior

Ground Forager

Emperor Geese appear to be monogamous in their mating system and will mate for life. When they arrive on nesting grounds in spring, most Emperor Geese are already paired and accompanied by their year-old young. Courtship displays, rarely observed, seem to involve head-dipping motions. Females make the nest and perform all incubation duties as males stand watch, attentive for foxes, people, gulls, or other geese that might approach the nest too closely. Both parents defend the nest and young using distraction displays, hissing, spreading the wings, and lowering the head and neck. Males are intolerant of other male Emperors near the mate, especially before the first egg is laid. Females not yet on eggs also chase females. Although Emperor Geese often forage among flocks of Cackling Geese, Snow Geese, and Brant, they do not tolerate them in the nesting territory. The territory defended varies greatly, as nests can sometimes be less than 50 feet apart or hundreds of yards apart. As with many other geese, Emperors remain in family groups from summer through spring. When foraging, families often perform threat displays toward other family groups that try to forage too near.

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Conservation

Restricted Range

Emperor Goose populations appear to be stable in recent years in North America, according to data gathered by the U.S. Fish and Wildlife Service. Partners in Flight estimates the global breeding population at 98,000 individuals, ranks the species a 14 out of 20 on the Continental Concern Score, and places it on the Yellow Watch List for species with restricted ranges. A 2015 spring count in Alaska estimated 98,000 birds in total, including young of the previous year. In the mid-1960s there were more than 139,000 birds, but by 1986, just over 40,000 birds remained. Wildlife managers have suggested reinstating a moratorium on hunting and egg gathering if the population again falls below 60,000 birds. As the population has recovered, legal hunting of this species resumed in the United States in 2017. No information is available on hunting of molt migrants on Russia’s Chukotka Peninsula. The impacts of oil and other marine pollutants on this species have not been studied. Aside from hunting, the most serious conservation threat to this and other arctic nesters is likely to be the effects of climate change on their habitats, prey items, and plant foods.

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Credits

Bellrose, F. C. (1976). Ducks, Geese and Swans of North America. Second edition. Stackpole Books, Harrisburg, PA, USA.

Lutmerding, J. A. and A. S. Love. (2020). Longevity records of North American birds. Version 2020. Patuxent Wildlife Research Center, Bird Banding Laboratory 2020.

Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Schmutz, J. A., Margaret R. Petersen and R. F. Rockwell. (2011). Emperor Goose (Anser canagicus), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Sedinger, J. S. (ed.) (1996). The Emperor Goose: An Annotated Bibliography. Biological Papers of the University of Alaska 25: 1-71.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

U.S. Fish and Wildlife Service. (2015). Waterfowl population status, 2015. Washington, DC: U.S. Department of the Interior.

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