Update:

SecretarybirdNaturalScale was added.

This is a model tailored to Blender's unit.

The wing span is about 2.2m.

This is a 3Dmodel and animations of Secretarybird. 

This model(SecretarybirdNaturalScale) will be included in future bird packs($99) to be released.

The feature of the model is that it has a realistic proportion of the skeleton so that the pose folding feathers and the flapping animation is reproduced.

The flapping motion is not just a vertical motion but a three-dimensional motion of the humerus, ulna, and metacarpals is reproduced.

The animation set has basic items that you can move freely within the game engine.

note:To use Root Motion with UE4, I need 3dsMax.

How to import to the game engine

Animation names are listed in the documentation.