by Louise Flenner

On March 15 Columbia Audubon Society conducted its annual field trip to see the Great Blue Heron rookery and accomplish some birding at Gans Creek Recreation Area (GCRA).  The rookery is located along Gans Creek in an undeveloped part of GCRA. I have been counting the number of returning herons every year since 2014, always on the Ides of March. I’m happy to report that the number of returning herons this year is second only to 2017 (16). This year we counted 17 nests and 15 herons, up from 9 nests and 12 herons last year. It’s always a thrill to see them circling the nesting site or standing tall in the nest watching for a mate.

They generally arrive from late February to Mid-April. This period is called initiation and is defined as the period of courtship before eggs are laid and can last 2 months. Nest building begins after a pair has formed a bond. This can last from late March to mid-April and during this time the female begins laying eggs (usually 4 blue eggs). Hatching begins late April to mid-May. Since the herons do not all arrive at the same time, and because some have multiple nesting attempts, chick rearing takes place for many months. Once the chicks are 3-4 weeks old, parents begin to leave them alone at the nest. This makes them vulnerable to predators and the elements. Feeding time for chicks is a flurry of activity as fights between siblings break out and loud squawking fills the air. Chicks begin to fledge at 10 weeks of age and are usually gone by the end of August.

Once the trees of the rookery have leafed out in the Spring, it is almost impossible to continue to observe their activity in the nest. The sounds of the mature birds and the squawking chicks is, however, something like being in Jurassic Park.

Although the rookery is a destination location, GCRA has excellent birding opportunities. The group included Emma Buckingham, Trana and Tim Madsen, Barb Reed, Luke Rainwater and myself. We saw an amazing 37 species. One species of particular note was an American Bittern seen along the edge of one of several ponds on the property. We were also entertained by a Brown Creeper going up and down a tree. A couple of us got a quick look at a red fox. Everyone in the group was pleased with a great 3 hours of birding and it was hard to stop.