Though they are known for their excellent fishing skills, they also eat rodents, small birds, amphibians, insects, reptiles and other small creatures. When foraging, they stand silently at the waters edge, waiting for prey to come by, then they stab the prey with a quick lunge of the bill. They will also stalk prey slowly and deliberately.
Great blue herons nest in colonies which are typically found in mature forests, on islands, or near mudflats. The colonies may have just a few birds or up to several hundred. Great blue herons do best when they are free of human disturbance and have foraging areas near by. Nest building begins in February when a male chooses a nesting territory and actively displays to attract a female. The large nest is usually built high up in a tree. The male heron gathers sticks for the female who constructs a platform nest lined with small twigs, bark strips, and conifer needles. The female lays 2-6 pale blue eggs with both parents taking turns to incubate them. Chicks hatch after 25 to 29 days.