Laura Erickson's For the Birds

Great Blue Herons nesting in Sapsucker Woods On April 30, 2009, at 3:53 p.m., Brian Maltzan sent an email to staff at the Cornell Lab of Ornithology reading: “A pair of great blue herons are carrying sticks up to the snag.”

“The snag” is a large, long-dead tree in the middle of the pond, in full view of many Lab offices and meeting rooms. Brian’s email announced the first known Great Blue Heron nest in Sapsucker Woods. Several of us without windows found ourselves gravitating to the Sapsucker Lounge in the following days as the nest grew. The herons weren’t marked, so there was usually no way of knowing which bird was which. The Birds of North American Online says that males are usually the ones who bring sticks, and the four times I observed copulation and thus could be certain, it was the male who brought the stick. It was fascinating watching the two interact with elaborate displays when one or the other returned to the nest.

The first sticks were the hardest to place, but the nest grew, and by May 6 or 7, it was clear that there was an egg in there. We couldn’t see into the nest, but now the birds were taking turns hunkering down, we assumed to incubate. Both male and female Great Blue Herons have incubation patches and both take turns incubating. According to the BNA, the male spends more time on the eggs than the female during daylight. We watched the birds take turns incubating, and they continued nest-building and mating behaviors as well. The last time I witnessed copulation was on May 11.

According to the BNA, Great Blue Herons typically lay eggs at 2-day intervals, and it takes about 26 days for them to hatch. I was getting suspicious that an egg had hatched around June 4th or 5th. The parents kept standing up in the nest and looking down, touching or moving something hidden below, but we had no way of looking inside the nest to see what was happening. We started seeing stirrings of something white and fluffy by June 10, and I got a photo of a chick on June 11.

Within a few days there was evidence of three chicks. I sometimes saw them bobbing up and down in such a way that it appeared there might be four, and finally saw and photographed all four at once on June 17.

As they got bigger, the four could still disappear into the nest, which began to seem as bottomless as Mary Poppins’s handbag. By July, they spent most of their non-sleeping time preening and flapping their wings. When one or the other parent flew in, they all made interesting clattering sounds begging, starting out with heads and bodies raised but legs lowered, standing taller and taller as the feeding continued. All four made their first flight on July 30. All four fledglings continued to return to the nest for feedings and at nightfall through August 11.

If a pair of herons nests in the snag next year, we won’t be certain whether they are this year’s pair or not. If more than one nest is built next year, we won’t have any way of knowing whether other nesting birds are “our” young or herons that hatched elsewhere. We may have witnessed the inception of a breeding colony, or the habitat may continue to support one pair without attracting more. Whatever the future brings, the Great Blue Heron family of the summer of 2009 will long be remembered and treasured.

A series of photos taken throughout the heron’s nesting season is online at http://www.flickr.com/photos/48014585@N00/sets/72157621748114647/