The Melodious Blackbird, Dives dives, is a New World tropical icterid bird. It is a resident breeder from coastal eastern and southeastern Mexico to Costa Rica. Its range is expanding. El Salvador was colonised in the 1950s, and eastern Guatemala in the 1960s. Prior to 1989 there was only one Costa Rican record, but it is now easily seen at least as far south as San José, and it is expected to colonise Panama.
The adult Melodious Blackbird is a medium-sized icterid with a rounded tail. The male is 25.5 cm long and weighs 108 g. The slightly smaller female is 23 cm long and weighs 95 g. The adult plumage is entirely black with a bluish gloss, and the bill legs and feet are also black. The iris is brown. Females are identically plumaged to the males, but young birds are brownish black and lack iridescence. There are no subspecies.
The song is a duet between pairs, with a see note, followed by a whit and a Northern Cardinal-like whistle. The call is a metallic puitt.
The Melodious Blackbird inhabits a wide range of habitats, but avoids dense forest and thick undergrowth. It has adapted to human habitation and can be seen in gardens and on lawns. The Melodious Blackbird forages mainly on the ground for insects, but will also take nectar and ripening maize ears, as well as other plantstuffs such as the fruits of Gumbo-limbo (Bursera simaruba) and Trophis racemosa (Moraceae).
Breeding birds are highly territorial, and adults will attack predators like the Brown Jay, but small flocks form outside the nesting season. A breeding pair will give a display in which each bird spreads its tail, extends its wings, and ruffles its plumage.
Both sexes build a cup nest of plant material 3-7 m high in a bush or tree and line it with mud and dung. The female lays 3-4 brown-blotched blue eggs, which she incubates alone, although the male helps with feeding the chicks. This species is not known to be parasitised by cowbirds, which presumably has also contributed to its success.
This species has benefitted from deforestation, which has allowed its rapid range expansion through creation of suitable habitat.
The natives of Guatemala[verification needed] had a ritual in which they trapped a Melodious Blackbird, a mouse and a grasshopper, and warned them of dire consequences if they continued to damage crops. The three animals were then released to spread the news.