Hi John and all  . Yes unless bluebird houses are carefully  monitored and  House Sparrows  taken care off .  The  houses  do more harm then  good . Sparrows  even kill adult Bluebirds  and build  their nest over  the dead bodies.  They also nest in any nook or crevice they can fit in natural or  manmade . They also  can  sometimes build dome  shaped nests in open trees or tall shurbs . I will not go into it here [ I do not want to start a debate ]   the info on various means of dealing with the NON NATIVE  House sparrow  can be found on various websites  dealing with Bluebirds . So unless  folks are willing to  do a proper job  Do Not  but up nesting boxes  for any species that house sparrows can use .  Under no  cases should House Sparrows  allowed a nesting site  . Rip out nest, plug holes in anything  they want to nest  in and destory the adult ,eggs and young .
 
 
Happy Birding  and Happy Bluebirding 
Danny Poet
Queenstown , Maryland
 > Date: Sat, 29 Mar 2008 05:17:15 -0700> From: > Subject: [MDOSPREY] bluebirds and house sparrows> To: > >  After some online research, I found that house sparrows> will take over bluebird houses, even destroying bluebird eggs and killing nestlings. My question> is whether, by putting up bluebird houses and not monitoring them carefully, we are merely> breeding more house sparrows to the serious detriment of bluebirds.> > John Newman> Kensington, MD> 
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