Even a bird that is not exceptionally large can appear gigantic when viewed from below and without a nearby reference point.

Then there is another possibility:

The bird may simply have been an unusual individual.

A particularly large specimen of a known species can look extraordinary without representing an entirely unknown creature.

That possibility would fit the basic pattern of the sightings while avoiding the need to introduce a mysterious new species.

The Ten-Foot Wingspan Question

The claim of a wingspan approaching ten feet is one of the most dramatic elements of the story.

But it is also one of the hardest claims to verify.

To establish a wingspan accurately, an observer would need some reliable way to estimate the animal’s distance and compare it with a known object or measurement.

Simply looking at a bird overhead is not enough.

A bird flying closer to the observer will naturally appear much larger than the same bird at a greater distance.