As someone who has a great interest in observing bird nest sites and nest construction, I sometimes wish I could communicate directly with the birds. I would especially like more information on the discernment process, the determination that a particular site is or is not suitable as a nesting spot this year.
It is not rare to see a pair of birds begin what appears to me be nest construction, only to find out in later visits that the birds have abandoned this effort.
The most recent example is Black-capped Chickadees. On April 18, 2018, I was walking near the edge of the woods in Eliza Howell Park and focused my binoculars on a dead stump.
Chickadees are cavity nesters and they sometimes nest in an old woodpecker holes and sometimes dig out their own. When they dig their own, they usually do so in a rotten stump. So, when I saw a pair of blackcaps pecking away at the stump in April, I was excited, thinking that I might have found a chickadee nest for the first time in 5 years or so.
The next day, they were there again, so I asked Margaret Weber to see if she could get some pictures of the chickadees excavating a nesting hole. This is what she found.
Two things are noteworthy here: the two pictures are of different beginning openings and in neither is the bird chipping away. I began to think that maybe they had been doing some exploratory drilling and were, at the time of these photos, examining what they had found.
On subsequent visits, I did not see them at the stump again and the holes were not enlarged. They have remained the same for more than a week.
The question that I would ask if I spoke Black-capped Chickadee is this: What was unsatisfactory about this site?
While there were environmental factors (a couple Blue Jays active at the edge of the woods and a couple of humans watching), I suspect that, given the two starter holes, the reason has to do with the nature of stump wood. Perhaps it was not rotten and soft enough. After all, chickadees do not have woodpecker beaks. This is my current hypothesis.
When I next find an active self-made chickadee nest, I can compare how soft and yielding the wood is. I don’t know how long that will be, but probably before I am able to communicate directly with the birds.