If it can help it, the bird won't let you take it.

But what if the bird couldn't help it?

Look around the dock the bird is sitting on.

Or, should I say, walk around the dock the bird is sitting on.

When you step on the loose board at the lower-right portion of the dock, it jostles the bird.

What? The bird still isn't leaving?

Maybe it doesn't have to leave for you to grab the fish.

Have you tried stepping on the board again?

Step on the board a couple times. Watch what happens.

Each time, the bird takes a little while longer to land.

Once you have launched the bird high enough, pick up the fish before the bird lands on it.