Hey Emmaly!
Predicting the average velocity of swallows can indeed be very hard, especially when you need to account also for the aerodynamic drag according to the number and disposition of swallows in the flight. 
If this works for you, it’s the simplest solution: you can perform the first API call and check if the “pageCount” or “totalResults” parameter (or whatever it’s called) exists in the response. If it always returns the page count/total results when there’s more than one page, just use a repeater to paginate normally and then aggregate the results. Finally merge the first array with the second with, well, the merge function.
If your API doesn’t provide a “total count”/“page count” value even when there are more pages, then we’re talking cursor-based pagination or something of the sort (or perhaps a “less-than-great” API). In that case, I would recommend…
Recursion!
It can be tricky, but brew yourself a cup of your preferred beverage and check out this video to see how the idea works in Make: bt Advanced Pagination: Recursion example | Loom
Just adapt it to your use-case and you should be set. 
I hope this points you in the right direction!
edit: you can develop your own custom app instead as well. That would definitely use fewer operations so depending on the total number of results you have it might be a better option. You can find the pagination limits for custom apps here.