I beat it by just spamming jump as fast as I could, not caring about if I missed it as I was too fast for them to catch me. You might want to re balance that if that isn't the intended playstyle.
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Maybe you just nailed every jump? )
On the other hand, if you missed most of the jumps - it is not intended playstyle. But I was testing the game on that matter and never managed to run away from herons. So, I will certainly look at that, but for now, I think that you are just ultra lucky(or skilled:)