There were two Green Heron (Butorides virescens) nests at the disused boat basin at Sealevel, NC during the summer of 2018. We didn't discover the first nest until "adolescent" birds were seen in the mid to late June timeframe.

Of the first nest, we don't know how many eggs were laid, but 5 birds fledged. The immature birds sorted themselves out into two groups: a group of 3 larger birds and a group of 2 smaller birds. The group of 3 hung out in the open, perching and jockeying for position on an old bare tree snag. They were very conspicuous and didn't bother to move or hide when we came out into the yard or even stood ten feet away.

Adults visited a few times and the youngsters annoyed them for food, tapping the adult's bills and heads in attempts to get them to disgorge food. This was earlier in June and unbeknownst to me, the adults may actually have been sitting on the second nest (I was unaware of its presence until later in June when I saw the chicks). The adults pretty much ignored the juveniles' attempts to get food from them. I was kind of surprised by this because I thought the adults had stopped feeding the juveniles fairly early in the juveniles' development. But it may be that this was a second group of adults and not the parents of the juveniles.

That is a big question for me because the literature states that these birds only have one nest per season. And yet I never saw sufficient numbers of adults (more than 2 and of those, mostly just 1 at a time) to account for two nests at the disused boat basin. The second nest was so much later in the season and the adults had stopped feeding the juveniles from the first nest so... I keep wondering if the same pair of adults actually had two nests. I'm probably wrong, but judging by the behavior and timing, it just seems like a possibility.

Anyway, in mid-June I thought there were only 3 young birds from the nest until I saw the other two. The group of two were smaller and much shyer. They preferred to stay in the shadows of the Virginia Creeper and bay bushes around the pond. If we approached the pond, those two would often edge further back into the bushes where they could not be seen (or photographed). In fact, they were so much shyer that I was not able to capture any photographs of them.

When they decided to leave the nest site around June 26, the shyer group of 2 left and flew away to other sections of marsh around Nelson Bay pretty much at dawn. The group of 3 again, as was their wont, strutted around the lawn and dock, out in the open, before they made any attempt to fly to nearby marshes around the bay. They were quite bold and unafraid.

The group of 2 did not appear to return to the nest site after once fledging and leaving it--or at least I was unable to identify them if they did. Or they may have returned/left during dawn and evening hours when I was not watching the site.

The group of 3 however were noticeable as a group all around Nelson Bay for the rest of the summer. They routinely flew back together and landed as a threesome on docks in the area and frequently made it back to the nest to roost at night.

On July 10, I noticed the "gang of 3" had returned to the boat basin and they were very much annoyed by finding an adult Green Heron there, visiting the second nest. One of the gang of 3 and the adult raised the feathers on their heads and made aggressive/annoyed/dominance displays at each other. This can be seen in this observation (although I was only able to photograph one of the herons): https://www.inaturalist.org/observations/139127633

However, the adults visiting the 2nd nest were very secretive and usually made their visits at dawn/dusk and other times when the juveniles were not around to harass them.

Which actually made me worry about the survivorship.
Theory: This is a question I now have and have not been able to answer because we had no way to band either the adults or the juveniles while we watched them. We therefore don't precisely know which bird was which or which have returned in more recent years.

Given the above, I now wonder if the bolder juveniles survived quite as well as the more secretive ones. True, the bolder ones apparently--given the size differences in the young--got more attention and food from the adults and were therefore larger. BUT (this is a big "but") the smaller, more secretive ones might be more adept at avoiding predators due to their more secretive nature. They started out smaller, but they may have been more skilled at avoiding detection and therefore, more able to survive.

Another factor however will be health and ability to migrate, and the larger, bolder juveniles may have the edge there.

So as I mentioned, I cannot come to any conclusions about this since we were not able to band any of the birds (our banding license had been long expired by 2018). But it was interesting to watch them.

Posted on October 17, 2022 05:04 PM by amypadgett