The ultramarine flycatcher or the white-browed blue flycatcher (Ficedula superciliaris)

Usually singly, though sometimes in mixed hunting parties in the winter. Keeps largely to the low trees and bushes, feeding among the foliage canopy, not venturing much into the open. Constantly jerks up its tail, often accompanied by fluffing of head feathers and trrr note, especially in proximity of nest. Diet is mainly insects.