By Jennifer Thorpe
A frequent sight along the Thames River Valley is the majestic Great Blue Heron. With a length up to five feet and a wingspan up to seven feet, the Great Blue Heron is the largest of the North American herons. Standing silently and perfectly still or stalking their prey with careful slow steps, their hunting success relies on their ability to strike prey with lightning fast speed. Found throughout North America, herons are opportunistic hunters who will eat fish, amphibians, reptiles, small mammals, insects, and other birds, often defending their territory from other herons in dramatic displays.
Though they prefer solitude for hunting, they are known to nest in colonies that range up to five hundred nests in size. Nests are built up to a hundred feet or higher in marshy areas but are also found on duck blinds, channel markers, or artificial nest platforms. In a typical colony, there are several nests per tree.
Males will arrive at the colony and chose a nest site first, then court the females that pass by. Pairs are usually monogamous during mating season but choose new partners each year. During nesting-building, a process that can take three days to two months, the male will present nest material to the female, who will weave them carefully into the nest. Depending on the nesting site, nests can measure up to four feet across and three-and-a-half feet deep. Mating pairs can also be observed performing pair-bonding displays such as a ritualized greeting, stick transfers or a nest relief ceremony where birds will raise their plumes and “clapper” their bill tips.
Herons lay a clutch size of two to six pale blue eggs with an incubation period of twenty-seven to twenty-nine days. When the fuzzy grey nestlings hatch, they open pale blue eyes which will turn to brilliant golden yellow when mature. Nestling period ranges from forty-nine to eighty-one days.
There have been several heronries in Perth County. Typically, they will be in continuous use for four to five years until the herons move to another location; they tend to return to former sites within twenty years, after the trees have a chance to regenerate. Black Creek Heronry, purchased by Thames Talbot Land Trust (TTLT) in 2011, is a four-and-a-half-acre property that has been a nesting site for the Great Blue Heron for at least thirty years. It is a silver maple swamp on clay soil that remains wet most of the year; over twenty nests were counted in 2010, but it is currently uninhabited. These protected areas are important for herons whose breeding grounds are often impacted by traffic, logging, motorboats and other disruptions.
Homeowners with water features in the backyard have often been startled to find herons helping themselves to any fish or frogs to be found. Allaboutbirds.org offers the following backyard tip: put a length of drain pipe in the water where fish can go to hide from the Heron.
Our feature photograph comes from accomplished nature photographer and St Marys resident, Herman Veenendaal, who captured parent and chicks this February in Florida. Dedicated and respectful in his pursuit of stunning photography, some of Herman’s recent work will be featured at the Station Gallery in St Marys, in a show opening May 11th. Visit stmarysstationgallery.com for details.