The Great Blue Heron rookery on the small island offshore at the North Mississippi River Regional Park north of downtown Minneapolis is offering a unique bird-watching opportunity right now. It’s special, and it won’t last but a few more days. About 50 herons – perhaps 25 pairs – are remodeling last year’s nests as they prepare for eggs, incubation, and babies. There are about 60 nests high in the island’s trees, not all nests in use right now. The island is within a stone’s throw of the paved park paths along shore. The trees lining the shore have yet to sprout leaves, so your view is relatively unobstructed. It won’t stay that way for many more days. Birds come and go. I assume it’s the males making the trips to fetch sticks that the female accepts and works into the nest structure. Some birds go upriver to find sticks, some simply drop to the island floor, and one I photographed several times simply flew 50 feet to an unoccupied nest and borrowed sticks from it. You’ll find the park visitors’ center immediately to the right of the 49th-53rd Street exit off I-94W. The island is a 3/8-mile walk downstream from the visitors’ center. Follow the paved paths nearest the river. Binoculars are a good idea. A spotting scope will almost put you in the nest with the birds.