Tuesday, May 21, 2013

Building the Nest

This photo was taken around eleven AM on the first day of nest building and you can see she already had a fairly substantial nest constructed. At this point in building, the nest is made entirely of leaf matter. Notice the piece of cellophane incorporated into the nest. I had seen that piece somewhere out on the lawn the day before. For some reason, Wood Thrushes like to include paper in their nests.

Preferred leaves seem to be those that are thin (and soft) and already beginning to flake off. I figured she would construct a nest similar to a robin, another bird in the thrush family, so I kept watching for her to start bringing in mud to line the nest and stiffen up the walls.

At first, she was bringing in leaves at a fairly fast pace, placing them and tamping them down with her body, then going for more. As building progressed, however, her pace slowed, not because of fatigue, but because she was taking more time at the nest in "tightening" it up and creating the bowl-shape.

So, how does she create the bowl-shape of the nest? She uses her breast to tamp the leaves over and over again, turning in different directions. She pushes with her legs while her wings are spread slightly and uses her breast to tamp nest into a bowl shape. As the nest neared it's finish, she spent more time doing this. This step wasn't easy to film. This photo is about the best one showing her with her wing spread.

I kept waiting for her to bring in some mud like I had seen in the past with a robin that was building a nest, but I never saw it. I'm not sure why, but I don't think she used any in building this nest. The final phase is when she adds soft materials to the inner portion of the nest where the eggs will lay. I can't identify the material in this photo, but you can tell it is soft.

It took her three days to build the nest and over the next couple of days after that, I thought maybe she had abandoned the nests. Because she hadn't brought in any mud, I didn't think she was finished, but she was no longer building either.

In this photo, taken near the end of construction, you can actually tell she has rootlets. I don't know where they find them but I would guess she actually has to dig them out of the ground. It finally dawned on me that she was laying her eggs, one a day, and then watching over the nest from nearby branches. They do not begin sitting until all the eggs are laid.

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