A creature with a truly gigantic wingspan would be extraordinary.

The largest flying birds known today are impressive, but there are physical limits on how large a bird can become while remaining capable of sustained flight.

That immediately makes the idea of an enormous eagle worthy of caution.

Instead of assuming that an unknown giant species had appeared, experts would naturally consider more ordinary explanations first.

Perhaps the bird was a familiar species viewed from an unusual angle.

Perhaps it was farther away than witnesses realized.

Perhaps atmospheric conditions distorted its appearance.

Or perhaps multiple birds were involved.

The Problem With Judging Size in the Sky

One of the simplest explanations is also one of the most powerful:

People are surprisingly bad at estimating the size and distance of an object in an empty sky.

Imagine holding a small coin at arm’s length.

Depending on the distance and angle, it can appear to cover part of a much larger object behind it.