Adults of the nominate subspecies E. f. flavogaster have a brownish olive crown with a partially concealed white stripe in the middle of the crest.

[5][6][7][8][9][10][11][excessive citations] Subspecies E. f. subpagana has browner olive upperparts and yellower underparts than the nominate.

Most of the population of Veracruz and Oaxaca in Mexico move south of the Isthmus of Tehuantepec in winter.

It captures prey and plucks fruit by gleaning while perched and while hovering and with aerial sallies.

[5][8][13][14][17][18][excessive citations] The yellow-bellied elaenia's breeding season varies geographically, but with most of them being within the span of February to September.

Its nest is a cup made of moss and grass with lichens and bark on the outside and lined with feathers.

[5] Other renderings are "a series of burry teeotree or tee-tree notes interspersed with an occasional wurrTREE"[7] and "a leisurely and buzzy spud-deeer, spud-deer-dzz, spud-deer... over and over"[8].

It has an extremely large range; its estimated population of at least five million mature individuals is believed to be stable.

Its "[p]reference for more open woodland and widespread tolerance of converted habitats, combined with large range, suggest that this species is reasonably secure".