The collared whitestart or collared redstart (Myioborus torquatus) is a tropical New World warbler endemic to the mountains of Costa Rica and western Panama. Like other members of Myioborus, it is often called a “whitestart” rather than a “redstart”.
The collared whitestart is common at heights between 1500 m and the timberline in mossy mountain forests, ravines, second growth, and adjacent pastures.
The roofed nest has a round side entrance and is built on the ground or a steep bank, hidden amongst rocks, tufts of grass or under a fallen log. It is constructed from strips of bark, plant fibres, leaves, and grass. From March to May, the female will lay 2 or 3 white or cream eggs that are speckled with fine brown spots. Incubation lasts about two weeks, but other nesting details are largely unknown.
The collared whitestart is 12.5 cm in length and weighs 11 g. It has a chestnut crown bordered with black, and a black forehead. The rest of the upperparts are slaty black, and the tail is black with white edges. The face and underparts are bright yellow, with a black band across the breast.
The sexes are similar, but young birds are duller, with a browner back, weakly yellow underparts, and the head entirely slate-coloured, with no yellow on the face or rufous on the crown. The call is a sharp pit, and the song is a mixture of slurred whistles, warbles and trills.
The collared whitestart feeds on insects, frequently fanning its striking tail as it pursues its prey. It will join mixed feeding flocks, and will follow cattle and occasionally humans for the insects they flush. source