Mariton: Nesting Season Has Begun

April 25, 2019

by Tim Burris, Preserve Manager

A typical Bluebird nest.

About a month ago, I saw a pair of Bluebirds investigating a nest box.  Two weeks ago, we saw nest building in a different, but nearby box.  This week, there were two eggs in the nest when I monitored.  I expect to see a full clutch next week.

Two Bluebird eggs already.


Most likely a Tufted Titmouse nest under construction.

Two birds that make similar looking nests are the Tufted Titmouse and Chickadee. (We have both Black-capped and Carolina Chickadees at Mariton, and because the two species hybridize, it is a common practice to refer to either species as just Chickadee.)  Last year I had several Tufted Titmice nests, so I have a good feel for being able to distinguish them from a Chickadee nest.  Moss is the common building material for both birds.  Tufted Titmice tend to add dry leaves, where Chickadees use hair to distinguish them apart.  The nest above is still under construction, which makes identity a little tougher, but I am pretty sure it is a Tufted Titmouse nest.  Nest week I should be positive.

A Chickadee nest waiting for eggs.

The nest above is a Chickadee nest. The hair is the key identifier for me.  As the female lays eggs, she will use the hair to insulate them until she is finished laying.  Then she will start incubating the eggs all at once.  It is common to find six, seven and even eight eggs in a Chickadee nest.