Complex sentence: The island could not support much more than that because there were three other species of birds that were living of the same resources, namely the Laysan Millerbird, the Laysan Rail, and the Laysan Finch.
Split into simpler sentences: The island could not support much more than that because, there were three other species of birds that were living of the same resources. The Laysan Millerbird, the Laysan Rail, and the Laysan Finch.