[1] It also preserves remains of the body, primary, secondary feathers and a bastard wing which have been covered by layers of limonite as a result of the fossilization process.

[1] Later studies estimated that it had a weight of approximately 45 grams (1.6 ounces) and total wingspan (including feathers) of about 26 centimeters (10 inches), giving it proportions similar to those of a common kingfisher (Alcedo atthis).

While most early birds had wide sternums, Eoalulavis had a very thin one, with an expanded front end tapering to a point as well as a rear tip with outward-pointing extensions.

[2][6] The wide presence of this trait in both Enantiornithes and Ornithuromorpha, the clade which comprises modern birds along with their fossil counterparts, suggest that the development of the alula, and the flight capabilities that it implies, occur early in the avian evolution, presumably in the base of Ornithothoraces.

[2][9] The presence of alula and a complete set of aerodynamic asymmetric feathers arranged forming a modern wing,[10] indicate well develop flight capabilities, as in many other enantiornithean taxa.

The study also found that they were capable of continuous flapping flight, but were likely unable to glide due to having a high body mass to wingspan ratio.

[4] The locality of Las Hoyas was in the Barremian a seasonal subtropical wetland ecologically dominated by fully aquatic organisms (e.g.: holostean fishes).