About numbers

Hi guys,

This is some part of describing the scene of birds' ascent."

When you say "one, two, three hundred -- then a thousand at a time -- in long horizontal lines",

how many birds do you think they refer to?

I mean, "one bird, two birds, three hundred birds" OR "one hundred birds, two hundred birds, three hundred birds"?

Which one is possibly right?

Any comments are welcomed.

Thanks

pb