Update:

BowerBirdNaturalScale.blend was added.

This is a model tailored to Blender's unit.

The wing span is about 25cm.

This is a 3Dmodel and animations of Vogelkop bowerbird. 

https://www.youtube.com/watch?v=UbXoWA2pIC0

https://www.youtube.com/watch?v=Y1N1ZAqpaeo

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 are 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.