Relief features of specific “ornitogenic” geosystems of small islands in the North Pacific were studied. It is shown that large agglomeration of colonial sea birds may serve as system-forming factor, which provides creation of specific nano- and micro-landforms occupying almost the whole island. A few types of such landforms and their groups were revealed: hummocks, holes, tracks, nest and “fly up” areas, etc. The trampling is mainly a cause of high variety of ornitogenic microrelief, but the digging of holes is the most important geomorphologic factor. Products of metabolism also contribute relief formation. Birds are the main exogenic agent of relief formation on the small islands with large birds colonies.