I'm currently reading Ad Alpes and came across the following sentence:
"Nonne sunt qui putent earum volatu res futuras portendi?"
Now, as I understand it the meaning of this sentence is: "are there not those who think/believe/consider that by their [birds'] flight the future is foretold?"
So, my beginner's question is: why does the verb take the gerund form and not the infinitive? Am I mistranslating the way in which foretold is being used?