This is a relatively short mission that sees you making good use of your Dead Eye skill set. Make your way to Abigail (indicated by the 'A' on the map) and then head outside to scare off those pesky peckers.
You should notice a flock of the blighters at the top of the corn stack, so target them first and scare them into the air. You need to ensure that the blue bar depicting the amount of corn left doesn’t reach zero, otherwise its game over.
The birds don’t initially want to fly away, so they’ll keep circling around the corn, so switch to your Dead Eye mode and line up as many shots as you can get away with. Blast them out of the sky and as long as you can keep this up, they’ll eventually fly away and annoy someone else instead!