Eubucco
All members of this genus are completely sexually dimorphic
Eubucco is a genus of colorful birds belonging to the Capitonidae family. They live in humid forests in South and Central America, and their range is virtually totally allo- or parapatric. Members of the genus Eubucco are sexually dimorphic, with stubby yellowish bills, green backs, yellow to the neck or underparts, and red to the head, at least in males. They are primarily frugivorous but sometimes eat arthropods and are usually observed individually or in couples.
Individuals in this genus prefer lowland tropical forests, mainly in Asia and Central and South America. Wide varieties of ornamental trees yield bountiful fruits that attract barbets into gardens, towns, and even city parks, especially in Asia and Africa, where cities like Nairobi and Harare welcome barbets all year.
Species in this genus
Red-headed barbet
One of the prime examples of sexual dimorphism