Animalia Life
Anas platyrhynchos
SUBFAMILY
Anatinae
TAXONOMY
Anas platyrhynchus Linnaeus, 1758, Europe. Seven subspecies.
OTHER COMMON NAMES
English: Greenhead, koloa; French: Canard colvert; German:
Stockente; Spanish: Anade Azulуn.
PHYSICAL CHARACTERISTICS
19.7–25.6 in (50–65 cm); 1.7–3.5 lb (750–1,580 g). Green head,
brown chest, blue speculum.
DISTRIBUTION
A. p. platyrhynchus: widespread throughout the nearctic, in
palearctic from Iceland to Kamchatka and south to the
Mediterrean; winters on most of Pacific coast from the Aleu-
tians to California, southern half of the United States, northeastern
Mexico, the West Indies, northern Africa, and from
Iraq west to southeastern China. A. p. conboschas: coasts of
southern Greenland. A. p. fulvigula: coastal Alabama west to
Florida peninsula. A. p. maculosa: Gulf coast from Mississippi
south to central Tamaulipas, Mexico; winters south to Veracruz.
A. p. diazi: southeastern Arizona to western Texas and
south to Mexico. A. p. wyvilliana: Kauai, Oahu, and Hawaii,
Hawaiian Islands. A. p. laysanensis: Laysan Island, Hawaiian Islands.
Populations elsewhere are introduced.
HABITAT
Shallow and calm waters of all types of natural or artificial wetlands
and saltwater and brackish water. Prefers some vegetative
cover.
BEHAVIOR
Territorial to midincubation. Males then abandon their mates
and territory. The c. 39.54–274.29 acres (16–111 ha) large,
overlapping territories are defended aggressively. Forced copulations
occur. Typical
BEHAVIOR
s are the grunt-whistle and headup-
tail-up displays used in courtship. Migratory.
FEEDING ECOLOGY AND DIET
Feeds on water by dabbling, head-dipping, upending, and
rarely diving, and on land forages by grazing and probing.
Omnivorous diet includes terrestrial and aquatic invertebrates,
fish, amphibians, and various plant parts.
REPRODUCTIVE BIOLOGY
Seasonally monogamous. Breeding begins Feb.–Jun., depending
on locality. The nest is made in a cavity or the ground.
Generally lays 9–13 eggs; incubation c. 27–28 days; fledging
50–60 days. Becomes sexually mature at 1 year.
CONSERVATION STATUS
Common. Only Hawaiian subspecies are rare. A. p. laysanensis
considered Vulnerable and listed on Appendix I of CITES.
A. p. wyvilliana considered Critically Endangered. The other
subspecies are common. A. p. diazi may be threatened by hybridization
with southward spreading A. p. platyrhynchus.
SIGNIFICANCE TO HUMANS
Hunted for sport.