Océanite téthys Hydrobates tethys

Very small storm-petrel. Fairly common in warmer offshore waters and not usually seen from shore. Plumage black overall with large, wedge-shaped white rump patch and slightly notched tail tip. Often feeds and associates with Least and Black storm-petrels. Similar to slightly larger Leach’s and Townsend’s storm-petrels, but flies with deeper wingbeats, and white rump patch is larger and longer.