Meanings of realises to in English

What happens when she finally gets through and the operator realises to whom they're speaking?

Consequently the pilot of a dirigible realises to the full the imperative urgency of keeping beyond the point-blank fire of aerial mosquito craft.

It realises to us in a way which nothing else can, the littleness of human intelligence in the face of that which transcends human intelligence.

The poet realises to his enormous (and unreasonable) horror that the small creatures swooping so beguilingly under Florence's Ponte Vecchio are not swallow but bats.