The guards I have seen are in bird products catalogues. They are attached to
the box around the hole & stick out a bit. It may be too late this year but
certainly worth investigating for following years. Good Luck.
BWP

>From: "Lawrence, Miriam" <[log in to unmask]>
>Reply-To: Vermont Birds <[log in to unmask]>
>To: [log in to unmask]
>Subject: Re: [VTBIRD] house sparrow eviction questions
>Date: Wed, 1 Jun 2005 11:48:05 -0400
>
>Barbara Powers wrote:
>
> > If you attached a guard around the opening of the box, the bluebirds &
>tree
> > swallows can get in but not the unwanted birds. It might be worth a try.
>
>
>
>Barbara,
>
>What type of guard did you have in mind? The materials I've read say that
>sparrows can get into any hole that is big enough to allow tree swallows
>and
>bluebirds access.  Is there a type of guard that is an exception to that?
>I'd love to know if there is.
>
>Apparently "sparrow spookers" can be very effective against sparrows while
>being tolerated well by swallows and bluebirds, but they have to be put up
>when the bluebirds or swallows have just started laying eggs, to ensure
>that
>they don't get scared off during incubation.
>
>http://www.sialis.org/sparrowspooker.htm
>
>Our swallow/bluebird families seem to be too far along to use spookers this
>season, but I'll definitely plan on it next summer.
>
>Thanks,
>Miriam