Blue-gray Tanager, Tangara azuleja

The Blue-grey Tanager is 16–18 cm (6.3-7.1 in) long and weighs 30-40 grams (1.1-1.4 oz.) Adults have a light bluish head and underparts, with darker blue upperparts and a shoulder patch colored a different hue 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.