Answer:
3 to 5
Step-by-step explanation:
As you can see the ratio of parrots to birds is actually first 12:20, we can reduce that number to the smallest possible by dividin it, the ideal would be to leave the ratio on a 1 to something, but if we can´t do it on whole numbers we have to leave the smallest whole number possible.
So 12 and 20 are both divisible by two, we can do that, and then be left with:
6:10, we can divide it again by 2:
3:5, so as we can´t actually divide it any further, that would be the ratio.