Bluebird and Small Cavity Nester Conservation
Sialis - Bluebirds and other small cavity nesters


Taylor Brooke Winery Nestboxes - 2009

Taylor Brooke Winery has nine nestboxes in their vineyard, but in 2007 all were occupied by House Sparrows (HOSP). After implementing a House Sparrow management program, Taylor Brooke now has bluebirds! Two nestings in 2008 produced ten bluebirds. Bluebirds and Tree Swallows eat insects which helps with pest control. Nestboxes for songbirds, owls and bats in also help maintain biodiversity in a vineyard landscape. More.

House Sparrow Eggs
House Sparrow eggs - see more photos
Pinkies.  Photo by Bet Zimmerman
8/2/2009 - pinkies (baby mice)
Grapes on the vine.  Bet Zimmerman photo
Taylor Brooke grapes ripening on the vine

HOSP are an introduced, invasive species that will attack and destroy the eggs, young and adults of bluebird and other native birds. In addition to being aggressive, they are extremely prolific. Successful bluebird landlords do not let HOSP breed in their boxes. Because they are non-native, they are not protected by the Migratory Bird Treaty Act.

Bluebirds are nesting nearby, and the owners, Linda and Dick Auger, are interested in hosting native birds such as bluebirds, tree swallows or chickadees. Since I have several bluebird trails in the area, I offered to get involved in a House Sparrow management program in 2008. Note that there are a number of other boxes on surrounding properties (and possibly bluebirds nesting next door.)

  1. The first step was putting hole reducers (1 1/8") on two decorative boxes that can not be opened for monitoring, cleaning or trapping.
  2. The second step was regularly removing all existing HOSP nests. On 3/31, the bulky nests filled a large garbage bag. The owner commented that within 3 hours of removing the nests, the HOSP were furiously rebuilding.
  3. The third step was starting a trapping program on 4/6 to remove HOSP that are nesting in the area. The HOSP will be donated to a local raptor recovery center. If the HOSP are not removed, they are likely to go next door to attack nesting bluebirds, and will not allow native birds to use the nestboxes.
  4. After local HOSP are trapped, the next step was to put up some HOSP resistant boxes (Gilbertson/Slot) and to outfit existing boxes with monofilament to attempt to deter HOSP. IF a native bird is able to get to the point of laying an egg, the box will be outfitted with a sparrow spooker.


  • In 2008: Ten bluebirds fledged from two nestings. Number of HOSP trapped: 27 (in live ground and inbox traps.) Many nests and eggs removed. All trapped birds are donated to a local raptor recovery cente See 2008 Log. I must say that I was amazed at how quickly we were able to reduce the local HOSP population enough to allow bluebirds to have two successful broods.

2009 Log:

  • 3/13/09: Cleaned out boxes. 2 had evidence of HOSP roosting (nesting material with numerous white-noodley feces, 2 (including slot box used last year by EABL) had mouse nests. Saw three bluebirds in the area. No HOSP seen.
  • 03/28/09: 1 F HOSP trapped, 3 active HOSP nests (1, 4, 7), a little mouse action (removed) on the slot box but bluebirds appear to have claimed it. 1 F trapped.
  • 4/5: Put out traps in 3 boxes that had HOSP activity but didn't catch anything. No bluebird nest start yet.
  • 4/12: Bluebird nest 1/2 grass, 1/2 pine, no eggs. 4 boxes with HOSP activity (farthest possible mouse), no luck trapping.
  • 4/19: trapped 2 F HOSP
  • 04/26: HOSP in slot box? 3 boxes had nesting material.
  • 4/27: trapped 1 M HOSP - total 6 so far.
  • 05/16: HOSP have claimed slot box. TRES in box 5.
  • 05/27: HOSP in slot box. Tree Swallows had 7 eggs. 7 HOSP eggs removed from 3 boxes, trapped 1 F, total 7 so far.
  • 05/31: HOWR attempt in slot box
  • 06/30: House Wrens (HOWR) attempt in far box
  • 8/2: Unfortunately HOSP and then House Wrens drove the bluebirds off, and no bluebirds successfully nested in 2009. The HOSP also destroyed the Tree Swallow nest with 7 eggs. As of 8/2, there were two partial HOSP nests (no successful nestings) and a box with mice nesting in it (placed on ground.)
  • 8/8: 5 HOWR hatched in the slot box taken from bluebirds and HOSP.

Links to more information:

Who does not welcome the beloved Bluebird and all that his coming implies? His cheery warble, heard at first as a mere wandering voice in the sky, heralds returning spring .... Snow may still lie in patches or drift in flurries; but when the Bluebird comes we know that spring is near.
- John B. May, abridgement to A Natural History of American Birds of Eastern and Central North America, 1930's

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May all your blues be birds!

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