Gabrielle saw 5 + 4 + 3 = <<5+4+3=12>>12 birds.
Chase saw 2 + 3 + 5 = <<2+3+5=10>>10 birds.
So, Gabrielle saw 12 - 10 = <<12-10=2>>2 more birds than Chase.
Therefore, Gabrielle saw 2/10 x 100% = 20% more birds than Chase.
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