Apparently this is a proverb that means "It will be obvious" or "You will know it when it happens." Alternate translation: "As vultures gathering shows that there is a dead body, so these things show that the Son of Man is coming" (See: [[rc://en/ta/man/translate/writing-proverbs]])
Vultures are large birds that fly together and eat the flesh of dead animals that they find. You could describe these birds this way or use the word for local birds that do this. (See: [[rc://en/ta/man/translate/translate-unknown]])