Scientific Journal (JRNL)
Two attempts of kleptoparisitism of Ospreys (Pandion haliaetus) by Great Blue Herons (Ardea herodias) were observed in Grand Teton National Park, Wyoming. Two herons vocalized and bill thrusted at Ospreys as they emerged from the water following dives for fish. Although both attempts were unsuccessful (the Ospreys failed to capture a fish), the intensity of the attacks suggest that Great Blue Herons may be capable of taking fish from Ospreys.
Squires, John R. 1998. Attempted kleptoparasitism of osprey by great blue herons. Wilson Bulletin. 110: 560.