Even for birds, things sometimes don’t go as planned. In fact, we’ve found that for Rose-Breasted Grosbeaks, life often doesn’t follow its intended course. None of the Grosbeak nests we’ve found have lasted until the chicks fledged, and many were “popped” (eaten) or abandoned before the eggs even had a chance to hatch. After six failures, but before we resigned ourselves to the apparent curse of the Pheucticus, we did a little research. Friesen, Cadman, and MacKay found that only 46% of the Rose-Breasted Grosbeak nests they kept tabs on made it to completion, i. e. 54% of their nests did not yield any fledglings (1999). Compared to our 0% success rate, 46% was looking pretty good. However, Dungay, Woods, and Nichols reported a success rate of only 32% (2001). Consultation of the Birds of North America account revealed that our Grosbeaks’ low success rate may also be a consequence of the fragmented nature of the available habitat. Despite their preference for fringe habitats, Rose-Breasted Grosbeaks also tend to have a lower nesting success rate in more fragmented habitats.
Taking all this into account, and pushing valiantly through the heartbreak of losing yet another nest, we decided we needed to make darn sure the nest was empty. We had assumed the happy Grosbeak couple was incubating when one or the other was constantly on the nest, which we first observed on July 2. This meant that there should have been eggs in the nest. To check for the presence of eggs, we used a very special piece of equipment: a nest mirror (also known as a mechanic’s mirror).
The basic plan was as follows:
Simple enough, right? We thought so. However, we forgot that the nest, although located relatively close to the ground, was also directly over a giant patch of honeysuckle. After several tries, Hilary eventually managed to hold the mirror in a position that reflected the image of the tragically empty inside of the nest to Emma and me, who were looking on intently with binoculars and a camera. Although our hard work revealed nothing but an empty nest, we felt we had accomplished something by figuring out how to look inside a nest that was way above our heads. Hopefully the next time we use our ingenuity to look in a nest, we’ll be greeted by the sight of happy little chicks!