Mexican Duck
Anas diazi
Both sexes look like a dark-colored female Mallard. Bill of male is dull yellowish; bill of female is mottled orange and black, like a typical Mallard. In flight, bright white underwings contrast with dark body. Note distinct white stripe in front of iridescent panel on upperwing, compare to Mottled Duck (limited range overlap). Usually in pairs or small flocks; wary in most areas, but in some city parks and urban settings has become fairly tame. In some areas of sw. US, hybridizes with Mallard, producing birds with variably intermediate features.
Identification
Both sexes of this 51–56 cm length bird resemble a female mallard, but with a slightly darker body. The Mexican duck is mainly brown, with a blue speculum edged with white, obvious in flight or at rest. The male has a brighter yellow bill than the female.
Taxonomy
Including the Mexican duck in the mallard is a relic from the usual practice of much of the mid-late 20th century, when all North American "mallardines" as well as the Hawaiian and Laysan ducks were included in the mallard proper as subspecies. This was based on the assumption that hybridization, producing fertile offspring, is an indicator of lack of speciation.<p>Rather, in these birds it indicates a fairly recent allopatric radiation, which has not yet established solid barriers against gene flow on the molecular level; mate choice is conferred by cues of behavior and plumage in the mallardine ducks, and this, under natural conditions, has precluded a strong selective pressure towards establishment of genetic incompatibility.
- Scientific name
- Anas diazi
- Authority
- Ridgway, 1886
- Order
- Anseriformes
- Family
- Anatidae
- Genus
- Anas
Range and habitat
Most of the population is resident, but some northern birds migrate south to Mexico in winter. The species also occurs widely, but in limited numbers, in Colorado in all seasons and there are photographs of birds referable to this taxon from Utah, Wyoming, Nebraska, and Montana.<p>It is a bird of most wetlands, including ponds and rivers, and usually feeds by dabbling for plant food or grazing. It nests usually on a river bank, but not always particularly near water.
Conservation
Although a species of least concern, the Mexican duck is undergoing a slow but marked decline due to destruction of habitat and overhunting. It hybridizes with mallards which are better-adapted to utilizing habitat altered by human activity and thus are spreading throughout this range. Concern has been expressed that this combination of factors may ultimately lead to the disappearance of the Mexican duck as a recognizable taxonomic entity (Rhymer & Simberloff 1996, McCracken et al. 2001, Rhymer 2006[dead link]), but fairly limited measures such as wetland preservation and preferential hunting of drake mallards would prevent this. The Mexican duck was listed as endangered species at the United States Fish and Wildlife Service in 1967 but was removed in 1978.
Photos
Distribution
Bird Calls
Other Birds
Fanti Sawwing
Psalidoprocne obscura
An elegant sooty-brown swallow with a distinctive long and deeply forked tail. Plumage has a greenish gloss if seen well. Female and juvenile have shorter tails, and the latter is brownish. Resident in some areas; in others, occurs only in the breeding season. Pairs prefer foraging over clearings and the edges of evergreen forest, open woodland, and cultivation, usually near water. Not very vocal, but emits faint squeaky notes and trills. The only other sawwing in Fanti’s range is Square-tailed, which has a much shorter, square-ended tail.
Kinglet Manakin
Machaeropterus regulus
Chunky little, short-tailed bird of lowland and foothill forest. Male is distinctive with bright red crown and bold white stripes on reddish belly. Female lacks red crown but shows faint streaking on sides unlike any other manakin. Inconspicuous; elaborate display dance infrequently seen. Found in the lower to middle levels of forest. Listen for its strong “chew” call.
Vanikoro Monarch
Mayrornis schistaceus
A rather chunky flycatcher, mostly dark slate-gray with a pale eye-ring and obvious white undertail. Sometimes cocks and slightly fans tail, especially if aggravated. Dependent on primary forest. Apparently tolerant of old logged areas, but easily disturbed. Voice is a typical scolding “tchatchatcha.”
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