After monitoring bluebird boxes for several years I am curious about Tree  
Swallow nesting habits.  By the time the juveniles fledge the box is full  of 
fecal matter.  The nest is full, it is glued to side of the box,  everywhere.  
Some (most?) birds are fastidious about removing fecal  sacks.  Is there any 
theory as to why Tree Swallow don't seem to care?  

Tom  Beal
Glenn Dale, MD PG  Co.