White-rumped Sandpiper (Pilrito-de-uroprígio-branco) Calidris fuscicollis

A Common Sandpiper (Actitis hypoleucos) on the left of frame began to chase the WRS and eventually caught up with it - the next four images show a violent attack in which the Common Sandpiper stood on the head and bill of the WRS and held it under water whilst savagely pecking at the WRS's "nether regions". The WRS escaped, flew a short distance away and continued to feed as though nothing had happened!!