Scrub Blackbird Dives warczewiczi Scientific name definitions

The Scrub Blackbird is a fairly common and ubiquitous roadside bird in the generally arid coastal regions of western Ecuador to southwest Peru. It is a mid-sized all-black icterid, with a relatively short tail but long legs, as well as a rather long slightly decurved bill, and the species is frequently found in small flocks in open wooded and agricultural areas. Confusion is most likely with male Shiny Cowbird (Molothrus bonariensis), but the latter species is smaller, shorter legged, shorter billed, and has more glossy plumage. Principally ground-dwelling, at least when feeding, nonetheless the birds prefer to remain reasonably close to cover, to which they can fly if danger is perceived nearby. Scrub Blackbirds are generally found at elevations below 1500 m, although there are records from Peru as high as 3000 m.

c. 21·5 cm (nominate); male average 85·5 g and female average 84 g (nominate), male 110 g (kalinowskii). Medium-sized all-dark icterid with long tail. Nominate race is wholly black, with a blue to green iridescence; iris dark brown; bill and legs black. Sexes similar. Juvenile is duller than adult, with plumage blackish-brown and mostly unglos­sed, blackest and with slight iridescence on head, mantle and breast. Race kalinowskii is much larger than nominate, with longer bill, and has violaceous iridescence.

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Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Xeric open woodland and scrub in lowlands and foothills, agricultural areas, clearings, fruit orchards, parks and gardens, and residential areas, even in large cities (e.g. Lima, in Peru). Along almost rainless coast of Peru, found mostly around oases, riparian areas or irrigated farmland. Nominate race to 2100 m, rarely at 2800 m; kalinowskii to 3000 m.

Presumably resident.

Few detailed data. Diet presumably insects and other arthropods, also small vertebrates, fruits and seeds; reported as catching a lizard. Stomach contents include insects, fruit pulp such as cultivated mangoes (Mangifera indica), and seeds. Forages mostly on the ground. Often in pairs.

Song, usually by both sexes in duet, a rather pleasant mixture of warbles, trills and whistles, mixed with chattering and buzzing notes. Sharp “teeeew” call in flight.

Season Feb–May; a food-begging juvenile in Jun in Lambayeque (Peru). Presumably monogamous. Apparently less territorial than D. dives. Nest in Ecuador a shallow cup made from sticks, weeds, grass and pieces of banana leaves, with some cementing mud, mean external diameter 14·3 cm and height 8·4 cm, internal diameter 9·3 cm and depth 5·1 cm, placed 5–6 m above ground in tree, including Prosopis juliflora, Cordia lutea and a lemon tree (of seven nests, five along dry riverbed and two in an orchard); two nests found high in eucalypt (Eucalyptus) trees in agricultural area in Peru. Clutch 2–3 eggs, mean 2·8, pale blue with scattered dots and spots in brownish to black, mean dimensions 27·5 × 19·2 mm; no information on incubation period; nest­ling period 12 days. Nests parasitized by Molothrus bonariensiss, and observed to feed fledgling of latter.

Not globally threatened. Common and numerous. Tolerates habitat modifications. Appears to be expanding its range in both Peru and Ecuador.