Unicolored Blackbird
Agelasticus cyanopus
The unicolored blackbird is about 18 to 21 cm (7.1 to 8.3 in) long. Males weigh an average of 40.6 g (1.4 oz) and females average 37.4 g (1.3 oz). The species is sexually dimorphic. Adult males of all four subspecies are entirely black with a faint bluish gloss. Adult females of the nominate subspecies A. c. cyanopus have a brown crown, a thin yellowish supercilium, and blackish ear coverts. Their upperparts are brown with heavy black streaks. Their upperwing is brownish with rufous edges on most feathers. Their tail is blackish. Voice: Both sexes of the unicolored blackbird are thought to sing, an "alternating liquid shr-r-le rattles with series of repeated warbles or trills (wie-wie-wie-wie, chie-chie-chee, etc.". The species, contact call is chieg.
ID text from Wikipedia, CC BY-SA 4.0
Yellow-winged Blackbird
Agelasticus thilius
Male yellow-winged blackbirds average 17.9 cm (7.0 in) long. Males weigh an average of 33.5 g (1.2 oz) and females average about 29 g (1.0 oz). The species is sexually dimorphic. Adult males of the nominate subspecies are almost entirely black. Their marginal, lesser upperwing, and underwing coverts are yellow; the first two give the species its English name. Females have a dark brown crown, a wide buff supercilium, and dark brown ear coverts. The rest of their head and their upperparts are brown with wide dusky streaks and some chestnut edges on the lower scapulars and lower back. Voice: The yellow-winged blackbird's song varies among and within the subspecies. Males of the nominate subspecies and A. t. petersii sing variable "trills of 3–7 notes..., a whistled warble tréé-o-lay (or séé-you-there), and a similar warble ending with a strong nasal or buzzing tone (tree-o-láááy). The song of A. t. alticola is described as similar but less nasal. Both sexes make a sharp chep call.
ID text from Wikipedia, CC BY-SA 4.0
Where you might meet both
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Play today's Daily BirdPhotos and recordings are credited to their authors under the licence shown. Full profiles: Unicolored Blackbird and Yellow-winged Blackbird.