If you were a tree swallow at Wellfleet Bay this summer, you obviously had a good time. For the second season in a row, this species thrived and 57 chicks fledged after many seasons of bad luck and perhaps poor planning on the adults’ part.
Maybe they’re getting smarter by delaying nesting attempts until the weather settles down and real spring is in the air instead of late winter chill and rain.
Bluebirds can succeed raising a family a bit earlier than tree swallows because they will dig around on the ground for grubs and other goodies until the flying insects appear. But tree swallows are very dependent on these insects which never take wing until the weather warms up. Poor planning by the tree swallows before the 2012 season often resulted in adult deaths from starvation, sparse nests, and thin shelled eggs that broke or never hatched.
Of course, it must be noted that the absence of any raccoon predation for two years has been a great benefit, but nesting habits were the main reason for success. Despite the ability to start nests earlier than tree swallows, bluebirds had only 12 fledglings from five nesting attempts. Two of these attempts had eggs that were abandoned for unknown reasons.
Nest box competition or death of one of the adult pair is not uncommon, but it’s always a sad moment to discover such losses on our weekly rounds.
The chickadees began four nests but only two succeeded and 11 chicks fledged. In this case, pesky house wrens, with their habit of building many more twig nests than they use, appeared to be the culprits. How those male wrens have the energy to collect and wedge 100 or more little twigs into a nest box is amazing, but they don’t stop with just one nest. That way they can show their lady friends around the neighborhood and let her chose the mansion she prefers. After all this fuss, they succeeded with only six fledglings from one box.
House sparrow egg numbers were way down this year. Nineteen eggs were replaced with clay decoy eggs and the adults incubated the decoys anyway and then finally gave up. The decoy eggs have been a great success at Wellfleet Bay and it seems the house sparrows are nesting elsewhere(click here to see Betsy discuss this strategy). We’re very happy about that, as well as the promise of spring 2014, which, if you think about it, is really just around the corner.
Betsy Richards and Barbara Williamson have monitored Wellfleet Bay’s bird box nests for a combined total of 15 years. Their coverage area includes the day camp classrooms field, the boxes next to the dorms and the area near the solar panels off the parking lot.