Fretting Over Bluebirds

The Eastern Bluebirds have remained active at the suet feeder, and that's relieving my perpetual anxiety that our relatively small "meadow" will be abandoned at a moment's notice.  Perhaps I should stop worrying: the bluebirds have been fixtures for years in both cold and warm weather.  But one can't rest on one's laurels.  I make available what attractants I can: suet, of course.  a bluebird nest box (that they have used), some open space, and no use of insecticides.  Keep 'em interested? If You Build It They Will Come?  all good bits of advice for the fretful birdwatcher.  And I watch this lot with great interest.  Perhaps soon we'll even see the next generation...