We discovered the second nest at the disused boat basin a few days after the chicks had hatched so we were fortunate to be able to watch their development.

Here are the general aging guidelines I found from various sources including Bent's life history of birds of North America and the Birds of the World website run by Cornell University.

The aging information is only approximate (+/- 2 days, more or less)

• 1-9 Days; Parents stay or cover chicks
  Chick's iris is pale gray

• 3 Days; Down on back, neck and femoral track
  Beak is pink with black tip
  Eye ring is pale yellow-green

• 4 Days; Pin feathers appear

• 5 - 6 Days; Feathers on spinal, ventral, and femoral tracts
  Around day 6 the eye ring is pale green

• 7 - 8 Days; Feathers on neck
  Iris grayish white

• 9 - 11 Days; Feathers on head and tail
  Around day 11, beak more orange with black tip

• 14 - 17 Days; Eye ring greenish yellow
  Around 16th day, juveniles leave nest to explore surrounding area

• 17 Days; Iris greenish to yellow
• 21 - 22 Days; Eye ring greenish blue

• 25 Days; All juvenile feathers present although there may be down on the head
  Juveniles may fly with parents to feeding grounds

• 37 Days; All down gone

Sometime around June 26, 2018 there was a second nest at the disused boat basin that produced 3 chicks and 1 unhatched egg. The third chick was lost during a storm, but the other two chicks remained at the boat basin and only began to make experimental flights and forage elsewhere around July 24.

The juveniles from the first nest and one or two adults continued to visit the boat basin, especially in the evening, presumably to roost. The older juveniles and adults left around dawn if they had returned to roost.

In the development of the chicks in the second nest, it was interesting to watch them around day 9 because when the adults left the nest to forage, the chicks would poke around the nest area. By about 10 days they would experimentally bite twigs as if testing for edibility, but they never left the nest or ventured out of the cover of overhanging vegetation. In this observation, one of the chicks is biting a nearby twig. https://www.inaturalist.org/observations/138844436
Pin feathers were clearly visible and even at this stage, they were a greenish-blue (cyan) color, making the chicks identifiable as Green Heron despite their young age.

By around 11 days, the young were "flexing their muscles" and chestnut pin feathers were clearly seen on their necks and chests. The flexibility of their beaks was also very noticeable as they yawned. This flexibility can be seen on observation: https://www.inaturalist.org/observations/138844430
They frequently went to the edge of the nest to look around but didn't quite leave its shelter.

By approximately the 16th day after hatching, the chicks were starting to explore the area around the nest. By this time, some feathers had started erupting and the chestnut neck and cyan coloration of the wings and back were becoming more noticeable. https://www.inaturalist.org/observations/139127636

The initial feathers continued to erupt and by day 21, most of the juvenile feathers were present although they still had downy heads (and rear ends). They were much bolder by this point and were exploring the area around the nest as well as making experimental foraging attempts in the boat basin. In this observation: https://www.inaturalist.org/observations/139127649
the juveniles are approximately 24 days (give or take) and despite the feathers, bits of down are still visible here and there.

The immature herons at 24 days were attempting to forage in the boat basin and often caught small fish or crabs. The adults had stopped returning by this time (actually, they stopped well before this time) or only infrequently returned and did not appear interested in feeding the immature herons. I was rather surprised at how early in the juveniles' development the adults appear to have stopped regular feedings.

The two surviving chicks seemed to like to stay together, but this was more evident when they were between 24 - 30 days old. When they were younger, they individually explored the area close to the nest but didn't pay much attention to each other. As they grew a little older however, and moved 20-30 feet away from the nest, they preferred to remain close to each other. One would often look one way while the other looked the other way, as if visually trying to "cover the area" for potential threats. They were also very much aware of an osprey that had flown overhead and first one and then both turned to watch it.

In this observation: https://www.inaturalist.org/observations/139335118 both chicks have turned to watch an osprey flying overhead. The immature herons are 26 days old at this point. They were becoming very alert to the presence of other creatures including the osprey, gulls, and me.

The two immature birds roosted at the nest area and had always roosted by the time any adults or immature herons from the first nest arrived back to the boat basin to roost. When immature herons from the first nest arrived, if there were adults or even other siblings there, they often engaged in dominance/aggressive behavior. However, this seemed to be kind of "mock" or tentative because it never resulted in any of the herons leaving the boat basin. They would raise their head feathers for a few minutes and then everyone would settle down and move to hidden roosting locations in the shrubbery.

By 36 days, the two immature herons were flying and foraging, although they stayed together. They would often engage in dominance/aggressive behavior: https://www.inaturalist.org/observations/139335124
However, this behavior never resulted in one or the other leaving. It was just "mock" dominance. The two birds continued to forage together around the boat basin, dock, and shoreline for several more days before flying to nearby marshes to forage.

It was interesting to note that these two did not follow any adults to feeding grounds. They went together, on their own. However, by the time they were actively leaving to forage, the adults only infrequently appeared at the boat basin so perhaps the lack of attention by the adults (or lack of presence) encouraged these two to leave independently.

The 2 smaller immature herons from the first nest followed an adult to feeding grounds when they first left to forage. The 3 larger siblings from the first nest did not follow adult(s). They went out as a "gang" to forage in nearby marshes and frequently returned in the evening together to roost at the basin. The 2 smaller ones did not appear to return as often to roost or if they did, they did so during late twilight and in a much more secretive manner.

One thing that was interesting to me to see was that none of the immature herons attempted to feed each other or bring food to the nest, although part of their feathers-raised-bill-tapping may have been only part dominance and part wanting food.

I mention this because I noted on one occasion with Yellow-crowned Night-herons, one immature night-heron returned to the nest and disgorged food while another immature night-heron was present at the nest. Both night-herons appeared to be the same age. The night-heron returning with the crayfish behaved aggressively towards the other immature night-heron, forcing it away from the food it had disgorged. The other night-heron did, however, manage to sneak a small bite before the other night-heron gobbled up all the food it had disgorged.

The behavior was interesting to watch (I will try to post some photos from that observation, although the photos are very poor and dark). I did not note any similar behavior with the groups of Green Heron siblings.

Posted on October 19, 2022 04:35 PM by amypadgett