In a park, the ratio of number of birds to squirrels is $$8 : 5$$. One year later, the number of squirrels increased by $$20 \%$$ and some birds flew away. Given that the total number of birds and squirrels remains the same, find the percentage of the birds that flew away.~\uline{~~~~~~~~~~}~$ \%$ 
Overseas Competition->Knowledge Point->Combinatorics->Patterns of Figures->Change of Quantity