Yellow-crowned Tyrannulet is a small tyrant flycatcher about 10–11 cm long. It is recorded in river-edge forest, lowland evergreen forest, and secondary growth. The account describes catching small invertebrates in surface sallies near foliage and lists sound records from Ecuador and other countries.
The account gives a body length of about 10–11 cm.
It occurs in river-edge forest, lowland evergreen forest, and secondary growth; its feeding niche is surface sallies for invertebrates.
An extinction-risk assessment has not been added yet.