Non Restricted Heron Rookery

People were talking about Coon Rapids Dam on the Minnesota birding listservs. The great blue herons were returning to the rookery and there was a great horned owl using one of the nests. From my understanding, the owl has been there for the last few years--there's a plethora of nests for it to choose from but I've never made it over to see it. So I took a few minutes to go check out the rookery.

Some of the great blue herons were actively building nests, others were kind fluffed out as if they were too cold to want to deal with it. I couldn't tell right away which nest had the great horned owl. I followed the directions to try and see the fourth one from the right and all I saw were herons.

I systematically checked each nest. Heron...heron...heron...heron...oh hey:


You're not a heron! That's a little red-tailed hawk head! And the great blue herons don't seem to care. Granted, red-tails are a mighty hunter, but adult heron probably isn't high on their prey list. Young herons would be a possibility...but I wonder if red-tails do not like the fishy taste? The red-tail would have been in that nest before the herons arrived, so the herons are choosing to nest there despite the hawk. I wonder if the hawk has nested there before? I wonder if the hawk built its own nest or just refurbished an old heron nest?

great horned owl

I found some birders nearby and asked if they knew which nest had the great horned owl and they pointed to a cluster of heron nests away from the active clump that had no herons on them whatsoever. There in the center was a great horned owl. This cluster of nests was further back and I found it interesting that the herons nested next to the red-tail seemingly without any problems but gave plenty of space to the great horned--the owl would go for adult and young herons. I remember when I went to a rookery a few years ago and we found the night-heron remains with a big fat owl pellet in the middle. I wondered too if the early returning herons get the better nest spot farther away from the owls and if the later ones would be forced to take a nest next to the great horneds? Either way, the other active nests are in easy view of the great horns and I'm sure the owls will take a few nestlings from them. The red-tail is in easy view of the great horned...I wonder how that territory negotiation is going? The owl would have started nesting in January, the red-tail in early March, and now the herons. I wish I had more time to spend and watch the negotiations.

I also noted that almost every wire stabilizer had a staring next to it singing territory song. The holes that the wires go through are wide enough to easily fit a starling and the area on the inside must make a snug nest. Such enterprising birds.