Photo from my cell phone:
Some interesting facts regarding the heron nests...
Usually, nests are about 1 metre in diameter and have a central cavity 10cm deep with a radius of 15cm. This internal cavity is sometimes lined with twigs, moss, lichens, or conifer needles.
Great Blue Herons normally nest near the tree tops. In colonies made up of several species, they will take possession of the top of the tree and leave the lower branches to other species.
In the spring, males and females reach the nesting grounds at about the same time. Males settle usually where there are nests from former years. Each male then defends his territory in the tree where he plans to build a new nest or restore an old one. From that site, males put on grand displays and shriek loudly when females approach them. New mates are chosen each year. Birds aged two years or more mate almost immediately upon arrival, usually at the nest or, when one is not available, on a branch.
The building of the nest soon follows. The male gathers nest-building materials around the nest site, from live or dead trees, from neighbouring nests, or along the ground, and the female works them into the nest. Ordinarily, a pair takes less than a week to build a nest solid enough for eggs to be laid and incubated. Construction continues during almost the entire nesting period. Twigs are added mostly when the eggs are being laid or when they hatch.
Most female herons lay from three to five eggs in April. Incubation, which is shared by both partners, starts with the laying of the first egg and lasts about 28 days. Males incubate during the days and females at night.
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