How do you get a gecko egg in runescape?

Baby geckos can be caught with a box trap at Hunter level 27.

Orange - North-east of the Tai Bwo Wannai tree grove, also east of the Nature altar, and directly next to the Shaikahan.

Green - East of the Tai Bwo Wannai tree grove, also on the very north-east coast of Karamja (not on Musa Point, but the bottom right quadrant of Karamja where the Shaikahan is).

Blue - East and West of the small mine north of Shilo Village.

Red - In the middle of the Kharazi Jungle.