Like Navel Rock, Birth Island does not appear on the Town MapFRLG by default, only appearing when the player first arrives there. This is in contrast to the other Sevii Islands, which do appear on the Town Map. It also never appears in the PokéNav's map.E
Deoxys is summoned on this island. The player must solve a strange puzzle, by following a moving rock, until Deoxys appears. If the player doesn't follow the shortest path to the next position of the rock, the rock will move back into its original position upon interaction, resetting the puzzle.
A colored background means that the Pokémon can be found in this location in the specified game. A white background with a colored letter means that the Pokémon cannot be found here.
Birth Island appeared in the FireRed & LeafGreen arc. After battling against Red, Organism No. 2 retired to the Birth Island in order to heal the damage it had received when Pika's Thunder struck its core. In order to protect itself, Organism No. 2 encased itself in a pyramid-like protection called "Delta Shield", a combination of Reflect and Light Screen. Giovanni, however, took advantage of Organism No. 2's weakened state, and followed it. Using his Beedrill's Agility to cut down its movements and his Aggron's Brick Break to destroy the Delta Shield, Giovanni was able to capture Organism No. 2 with a Poké Ball specifically designed to catch the DNA Pokémon.
Trivia
While Birth Island does not reappear in Pokémon Omega Ruby and Alpha Sapphire, it is referenced near the end of the Delta Episode; after Mega Rayquaza destroys the meteor, a triangle emerges, darts about in the same pattern as the puzzle on Birth Island, and then breaks apart, revealing Deoxys.