Blue-gray Tanager

The blue-gray tanager is 16–18 cm (6.3–7.1 in) long and weighs 30–40 g (1.1–1.4 oz). Adults have a light bluish head and underparts, with darker blue upperparts and a shoulder patch colored a different shade of blue. The bill is short and quite thick. Sexes are similar, but the immature is much duller in plumage. The song is a squeaky twittering, interspersed with tseee and tsuup call notes.

The breeding habitat is open woodland, cultivated areas, and gardens. The blue-gray tanager lives mainly on fruit, but will also take some nectar, insects, and other arthropods. This is a common, restless, noisy, and confiding species, usually found in pairs, but sometimes small groups. It thrives around human habitation, and will take some cultivated fruit like papayas (Carica papaya). One to three, usually two, dark-marked whitish to gray-green eggs are laid in a deep cup nest in a high tree fork or building crevice. Incubation by the female is 14 days with another 17 to fledging. The nest is sometimes parasitised by Molothrus cowbirds. Two birds studied in the Parque Nacional de La Macarena of Colombia were infected with microfilariae, an undetermined Trypanosoma species, and another blood parasite that could not be identified. Two other birds, examined near Turbo (also in Colombia), did not have blood parasites.

T. episcopus prospers in some areas cleared by humans for grazing, but is not as attracted to buildings or high human or livestock activity. They continue to live in forests but eagerly move temporarily into abandoned pasture land for wild fruits and have been variously found to never forage or merely to forage less often in pasture that has livestock in it. T. episcopus is more common in secondary forest resulting from slash-and-burn followed by abandonment than in primary forest. T. episcopus is commonly infected with Blastocystis parasites, specifically Subtype 6 (ST6) which was exclusive to birds in that area. ST6 was never found in cows in the area, but it was unassessed whether T. episcopus shares ST6 with nearby domesticated bird flocks.