Your box may contain any of the following nests:


  1. Bluebird.  Neatly constructed of grass, the 4-5 eggs are pale blue or occasionally white.  If it has been over 15 days since eggs hatched and you find a well-flattened nest not disturbed, this indicates that the nestlings have fledged.  Remove the old nest (only if there is no sign of a new nest being built) promptly because this will encourage bluebirds to nest again in that box.

  2. House Wren.   The nest is large and made of twigs.  The 6-8 eggs are white, speckled with brown.

  3. Tree Swallow.   The nest is of woven grass, and lined with feathers.  The 4-6 eggs are white.

  4. House Sparrow.   A mixture of course grass, feathers, and trash make up these very large woven nests.  Usually there are 5-6 gray-white eggs, speckled with brown.

  5. Chickadee.   The nest is made of moss, plant down and lined with hair and animal fur. The 5-8 white eggs are speckled with reddish-brown.


It is important to the recovery of the bluebird that all nesting boxes be frequently monitored to detect blowfly and/or use by house sparrows.  Uncontrolled, these species will continue to place the survival of the bluebird in jeopardy.  Bluebird boxes that are placed in the field and not monitored may do more harm than good to bluebirds.


It's a good idea to inspect the nestbox after a heavy or prolonged rain.  If you find the nest quite damp or wet, change the nest.   Remove the nest and nestlings, build a new nest of dried lawn clippings, and replace the nestlings.  You may lose the nestlings with respiratory problems in a wet nest if you don't follow this procedure.


Check in early spring to see if the deer mouse or white-footed mouse has occupied the nestbox during the winter.  If so, remove the contents.  Then your box will be ready for the next bluebird occupants.

For further reading order THE BLUEBIRD, ITS FIGHT FOR SURVIVAL by Lawrence Zeleny, THE BLUEBIRD BOOK by Lilian Stokes, each $9.95 plus 10% handling, prepaid.  Available from the NORTH AMERICAN BLUEBIRD SOCIETY, Box 6295, Silver Springs, Maryland 20906.