And that year OP also responded.  The aluminum bird houses still standing near the south & north gates were installed with support of board member DR Roberts, at our urging. Originally there were 4, and now its down to 2.  Due to wear & tear

That design is for purple martin birds, whose diet is to eat flying insects, a non-toxic mosquito control.  We also were successful with installing 2 of those same style houses in the Md. section of Assateague Island. 

 And many local citizens also put them in their yards.  The martin house on our dock has been joined by some on several neighbors docks that we can see along our section of Manklin creek. 

Our dock's martin house is about 15, perhaps 20 yrs old, and has had repairs several times.  We still love seeing those birds arrive during the spring of most years.