Mariton: Tree Swallow Idiosyncrasies

May 10, 2013

by Tim Burris, Preserve Manager

One third of Mariton’s nest boxes have activity this week.  There are three Tree Swallow nests, and one has eggs.  

 Tree Swallow Adult

Tree Swallows are interesting cavity nesters.  The females are reluctant to leave the box when I stop to monitor nests.  It is an interesting gamble from an evolutionary standpoint.  Yes, it keeps House Wrens or other birds from moving in and taking over a prime nesting location.  On the other hand, if the adult is killed by a predator, then its genetic information dies with it.  Another risky Tree Swallow behavior is buzzing anything that ventures near the nest box.  While it probably scares off some things, it alerts every other nest predator to the location of an active nest and possible meal.  Obviously, the behavior works more often than not.  Otherwise the theory of Natural Selection infers that Tree Swallow populations would dwindle.  I for my part check boxes very quickly in order to cause as little disturbance as possible.

In addition to Tree Swallows, we have two Bluebird nests with eggs.  I expect to find baby Bluebirds when I monitor next week. 

Chickadees also have two nests with a total of 14 eggs.  In another box, I found a collection of moss.  It may be the raw materials for another Chickadee nest.  Time will tell.