Agelaius

The genus includes several species of New World blackbirds, most notably the widespread Red-winged Blackbird ( Agelaius phoeniceus ). These birds are known for their rapid development and highly territorial breeding habits. Developmental Stages

: They typically breed in marshlands, wetlands, or grassy areas near water, with females building deep cup-shaped nests lashed to reeds like cattails. Species Profiles yellow-souldered blackbird revised recovery plan - FWS ECOS

: They undergo a "thermoregulatory metamorphosis" over approximately 12 days , transitioning from an ectothermic-like state to being able to maintain their own body heat.

: Born altricial (naked and helpless), they possess one of the fastest avian growth rates , increasing their body mass by 9–10 times within the first few days.

: A single male often defends a territory containing a "harem" of up to 15 nesting females .