Unusual GBH Behavior

[Chris Hansen]

Do Great Blue Herons kill one another very often? About six years ago while driving through San Joaquin National Refuge I came around the corner to see one GBH standing upon the back of another that was prone on the ground. It was in early spring so I assumed they were mating. This was definitely not the case. As the one on the bottom kept trying to get up the other kept repeatedly stabbing it over and over. Finally the one on the bottom stopped moving and the one on the top got off and walked about ten feet away. The one that had been on the bottom staggered to its feet whereupon the other one came back and jumped back on it and stabbed it some more. It then got off again and moved away. Then any time there was any movement from at all from the one on the ground it would rush back and stab it some more. This went on for about ten to fiteen minutes until it was sure the other bird was dead. I see GBH a lot in the wild but this is the first and only time I have ever observed behavior like this.

Chris

[Axel Hildebrandt]

I have never seen this behavior in adult herons, seems excessive for a territorial dispute.

[Eleanor Kee Wellman]

I have seen siblings in the nest attack the weakest one but not adults out of the nest. Three siblings all attacked the smallest one this spring. Every time the bigger ones attacked the small one it would end up hanging over the edge of the nest and each time it moved it was attacked again. The injured one was not in the nest on my next visit.