ML131963041

Age

Not specified

Sex

Not specified

Observation details

Male with entirely greenish-yellow bill; was mated with/guarding a typical female Mallard. Plumage like a female Mallard, but much darker overall on body, approaching American Black Duck. Tail mostly dark with thin pale edging, while white edges above and below speculum were thinner than those on female Mallards. Male Mallard-like traits such as weak green iridescence on crown (only visible in well lit photos) and tail curls on upperside of tail are now (2022) apparently acceptable for "good" male Mexican Ducks in alternate (breeding) plumage. See: https://www.aba.org/mexican-duck-photo-essay/ and excerpt from Birds of the World account for Mexican Duck below (entire account found at: https://birdsoftheworld.org/bow/species/mexduc/cur/appearance). Photos. Definitive Basic Plumage Considered "Definitive Alternate Plumage" by Humphrey and Parkes (18), Palmer (11) and others; see above and Pyle (15,1, 16) for details on the revised terminology used here. Present primarily September–June in males and September–February in females. Male. Crown and nape heavily streaked dusky forming dark-capped appearance; back feathers and scapulars largely grayish brown, fringed pale when fresh; lower back and rump dark brown to blackish brown, fringed reddish brown; four central rectrices (r1-r2 on each side) dark gray and strongly recurved, often forming a complete circle; remaining outer rectrices (r3-r8) dark graish brown with pale fringing, darker proximally and paling distally until outer pair paler gray-brown with darker markings (see Figure 58 in 1). Sides of head, neck, chin, and throat pale brown to brownish gray, with prominent dark lores and eyeline (similar in color to crown) extending proximally to nape and bordering pale supercilium. Upperwing lesser, median, and primary coverts and primaries medium dusky gray; greater coverts and inner secondaries (speculum) with bright blue to greenish-blue secondary panel bordered on both sides by narow white bars, the outer web of s3 usually with some iridescent bluish, the inner secondaries (s3-s10) apart from the tertials with iridescent blue outer webs, black subterminal bands, and narrow white tips (Figure 56 in 1), and the medial greater coverts squarish with medium-broad white subterminal bands, extending proximally along outer web, and black tips (Figure 59 in 1); tertials brown tinged silvery gray, broad, long, and tapering to a fine point. Underparts below throat, including belly, uniformly dark brown with paler brown or rufous-brown fringing,the larger feathers with central dark U-shaped markings; underwing coverts bright white.

Technical information

Model

NIKON D500

ISO

1600

Focal length

500 mm

Flash

Flash did not fire

f-stop

f/5.6

Shutter speed

1/800 sec

Dimensions

4774 pixels x 3180 pixels

Original file size

4.28 MB