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


My Notes from NABS 2006

What I learned at the NABS 2006 conference in San Antonio (Bet Zimmerman, 4/30/06): - also see photo slide show.
  • Parts of Texas are very hot and humid. My husband gets sick on buses. I’ve been pronouncing the name of my own website wrong (sialis = sea-AL-is, not ceye-al-is), Keith’s name wrong (Kreyd-ler) and Zeleny’s name wrong (ZEL-en-ee).
  • The first birds we saw when we got off the plane were HOSP. The second were Starlings. The third were Pigeons. Then Mourning doves (that make a sound sort of like a barred owl). Then lots of BIG Great-tailed grackles (everything is bigger in Texas?) with brown, smaller females; Turkey and Black vultures, Chimney swifts and Tree Swallow. We think we heard an endangered Black-capped vireo at the Balcones Canyonlands. We saw a Hespid? rat (I couldn’t find this online) at the Lady Bird Johnson wildflower center (cute critter).
  • The best guacamole in the world is at Boudro’s on the San Antonio Riverwalk (also tasty Prickly Pear Margaritas). Made with sea salt, fresh cilantro, orange juice and sweet onions among other things. The water by the Riverwalk looks pretty skanky.
  • There were people at the conference who had one bluebird box, and others who had hundreds.
  • Doug and I made up a Bluebird Jeopardy game (which I will post online at some point) with some questions that managed to stump even the experts! Doug hammed it up quite a bit, and Keith was a Superior judge! When a fight almost broke out over scoring, Doug went to a commercial break (sponsored by Best Buy, Proctor & Grackle, and House Sparrow Depot.) (We made up the questions on the plane trip, lubricated by unlimited drinks in first class, an upgrade I earned by traveling for work nonstop for the last few years.)
  • David Shiels gave a talk on heat testing he’s been doing on various wooden nestboxes. (See his heat shield design at Shiels is a geologist.
    • Temperatures from 75-96 degrees F inside the nestbox can cause abnormal, asynchronous development. Temperatures over 105 are lethal. The optimal range is 96-105 according to a Cornell study (with chicken eggs?)
    • He used little i-button temperature loggers that were sensitive enough for him to tell if an adult was in the box, and how many nestlings there were and when they fledge! Each chick heats the box up 1 degree. The Sharper Image remote sensors work okay (pricier).
    • Nestlings that have died from temps 115-118 degrees are yellow/orange as opposed to normal pink. They are most likely to die from heat when they are 1-5 days old (as they are still basically cold-blooded). After that age they can pant. (Kridler)
    • Nestlings which are older (e.g., pin feathers) may be more susceptible to hypothermia because they are too big for the mother to completely cover them when brooding. (Kridler)
    • Shiels found a wooden NABS box draped with heat shield cloth that was poorly ventilated stayed at >105 degrees for more than 3 hours.
    • The Texas Bluebird Society box was the best single walled wooden box he tested – it stayed below 105 except for a few minutes. The slotted “breezeway” and light color really helped. For this short period of time, the adults can fan the box or stop sitting on the eggs to control the heat.
    • The WORST performing box in his tests was a standard NABs box! It was over 105 degrees for 5 hours! A weathered NABS box got as high as 139 degrees inside!
    • He tested an unventilated “stylish” box made out of mesquite, and it got to almost 110 degrees.
    • White boxes will reflect heat when they are newly painted, but have to be maintained or the effect is lost.
      The hottest time of day is between 3-6 o’clock. When the sun is at an angle, heat is hitting the side walls, so it’s not just the roof you have to worry about.
    • The best way to figure out where to put a box is to look for an area that is shaded at 3:00 p.m.
    • He uses “Weatherboss” to treat his boxes – non-toxic, no oils, water-based resin.
    • Shiels has developed some heat shields for the top and sides that have dead air in-between (separated with a sheetrock crew with a piece of plastic tubing over it as a spacer) that keeps temperatures lower and more constant. He said you can use plywood or anything – signs from losing politicians last a year and can b e had for free since they don’t bother picking them up.
    • He found heat shields in TX lengthened the nesting season considerably. He puts them on all four sides.
    • He showed a bluebird box that he put up in a family cemetery nest to his sister-in-laws grave that had a beautiful blue Texas Bluebird Society plaque on the heat shield. He got bluebirds the first year.
    • He's going to try to standardize his experimental parameters so others can test boxes.
  • Tales of Texas by Keith Kridler:
    • Keith was known as “The little Kridler boy that always had bird poop on his shoulder.” He started bluebirding at age 9. He started corresponding with Zeleny in 1975. If Keith were born today, they would probably have him on high doses of Ritalin – thank goodness for all that energy!
    • (I always thought Keith was an old guy. He’s only 2 years old than me.)
    • In 1958, neighborhood boys shot the last pair of nesting bluebirds on his family’s mink farm (in Ohio?)
    • Keith made a lot of his early boxes out of gourds because his father wouldn’t let him use the table saw after his first attempt. Gourds are okay if hung in the shade, although you can’t clean them out or properly monitor them, but they are free if you grow them yourself. They last about 3-5 years. They’re also lightweight, so Keith could make a “gourd skirt” around his waist and carry them/ride his bike with them (that must have been quite a sight!)
    • Harry Krueger started bluebirding at the age of 67. He wanted to get a banding permit and they told him he couldn’t because he didn’t have a college degree, so he went back to school at age 70. He was the first to document that bluebirds had 4 broods.
    • Irv Davis used radio-controlled traps (modified Joe Huber)
    • Keith has found bluebird nests in logs that were 2.5” in diameters.
    • Flying squirrels will kill adult bluebirds in a nestbox – he found 3 dead adults in one two-holed box 4.5 x 8”, with a flying squirrel in it (has photo)
    • He showed a foto of a bluebird nesting in the underside corner of a metal roof over a food stand at a football field.
    • He had a great photo of a purple martin in a bluebird nestbox next to a bluebird in a purple martin house.
    • Black widows are sometimes found in nestboxes (another good reason not to blindly stick your hand in a nestbox)
    • A snake trapped in polypropylene netting used in the Krueger snake trap will die in a matter of hours in 100 degree F heat.
    • Jack Finch started bluebirding at age 72 (he’s 89 now.) Doug (my husband) mentioned the CT DEP program “No child left inside” trying to encourage kids to explore and appreciate the outdoors and nature, as they will be the ones in the future who decide whether or not to protect the environment.
    • A cowbird can lay 40-70 eggs in a year. They don’t normally prefer cavities. Lots of ranchers have cowbird control programs – they just have to take a TX State Parks program and put their name in (no permits required).
  • Steve Garr gave a talk on Bluebirds – Not Just for the Country. He’s been raising bluebirds in urban/suburban areas for 28 years. It is NOT true that they rarely nest in cities (as NABs used to say) – if you have titmice and chickadees at your feeder, you can get bluebirds. Don’t wait for the bluebirds – if you build it they will come, and in the meantime you can provide nestboxes for other cavity nesters.
    • The best locations are areas where the grass is mowed.
    • They had mice problems when the grass got as high as the baffles. Mice that have over wintered in a box leave a horrid ammonia smell.
    • One trail owner thought he was raising bluebirds for years until he started monitoring – then he learned he was just raising food for predators. It may take predators 3 years to find boxes. When Garr put predator guards on his boxes, the number of fledglings doubled.
    • Possums will chew up a nestbox, especially if it’s made of plywood.
    • If you have wasp problem, you may need to monitor every day/every other day – one day can make a difference.
    • He showed a photo of a HOSP nest the size of a basketball that was in a tree.
    • Had another great photo of 3 HOSP nests in the holes of a “BP” sign at a British Petroleum gas station – VERY close together. (I saw nests about 8 feet apart in a car port.)
    • Baby Tufted titmice have no black on their crest. (Baby black crested titmice do)
    • Some bluebirds dump all their fecal sacs in one area (a little dumping ground)
    • Feathers in a nest don’t necessarily mean HOSP! (I’ve had bluebird nests with 1-3 feathers. Of course TRES nests have lots of feathers, but some new bluebirders who have never had them nest don’t recognize them. More than one new bluebirder has thrown out a nest to later discover it belonged to a native species!)
    • There is an annual bluebird day in Oak Ridge, TN where they hold an annual bluebird day with an intro talk and they sell 300 boxes.
    • Garr showed a tape recorder playing back bluebird songs with a male sitting on the handle of the recorder.
    • On his park trail he has found that the people who walk the trail regularly are their best allies, as they report any problems and confront people who appear to be messing with boxes. Most of their vandalism occurs outside of nesting season, in boxes that are not in plain view (as vandals tend to be cowards). They did lose one nest of TRES babies when a firecracker was exploded in the box. He finds education really helps. If a box is vandalized, it is immediately replaced.
    • He encourages backyard birders to put up boxes near the park trail, and has good success encouraging them to control HOSP. Another monitor said they stopped encouraging that as he found people were unwilling to control HOSP. They asked the room, and about 1/3 of people did not raise their hands when asked if they were willing to control HOSP.
  • Ivory billed woodpeckers (IBWO): David Luneau (the guy who captured the short video of the woodpecker in flight) gave a fabulous, fascinating talk. It would make a great hour long NOVA special.
    • Luneau showed Tanner’s footage – so clear! Weird herky-jerky motion by adult.
    • Only one IBWO was ever banded (Sonny boy, the young one shown sitting on that guy’s hat – photo by Tanner.)
    • Singer (sewing machine co.) cut down all the wood in that tract where Tanner studied in part for WWII supplies of boxes, crates, coffins and ammo pallets.
    • There was a very credible sighting in 1999 by a turkey hunter in LA.
    • The team that found the IBWP in 2004 looked for stripped bark, holes bigger than 3.5” x about 6 or 7”, and more irregular than a pileated (found about a dozen). It’s tough though, because some may be enlarged by other creatures.
    • The 2004 expedition had a total of 18 sightings by 16 people. Several “kent” calls were recorded last year, but they’re not certain they are not blue jays. It’s tough to distinguish double knocks (e.g., sometimes two trees rubbing together in the wind sound like a double knock)
    • There was a book signing of “Big Woods Bird,” a children’s picture book by Luneau’s wife. (Luneau has not written a book yet. Gotta have priorities.)
    • There was another expedition last year – no good sightings came out of it.
    • Sibley “declared” IBWO extinct in his guide. Maybe that’s why he’s questioning the sightings and video.
    • More info at his website (
    • Luneau said “It’s not up to any one agency or government – it’s up to the collective efforts of all of us.”


  • The NY Bluebird Society started after some New Yorkers were inspired at a 1982 NABS convention.
  • The Mississippi bluebird society went under in 2005. The Maine one is also gone.
  • NABS plans to add some coloring book pages to their website.
  • Spoke to Ron Kingston. He said people who have snakes climbing a stovepipe guard are using riveted guards. He had good luck with 4x4 hardware cloth tied to the box, and 32 gallon inverted garbage can on a purple martin pole. Barbed wire and rose vines with thorns do not deter snakes.
  • Dr. Gary McCracken talked about bats. He got very animated about wind turbines and thought they were one of the greatest threats to bat conservation, and predicted they would be responsible for some species becoming endangered. He said if the power companies would shut them down 10% of the time during the brief migration season, it would save them, but they are not willing to. He said bats fly 5-10,000 feet in the air and are eating moths up there. He said a survey was done and the average American is willing to spend $19 to save a bald eagle. (My box pole set up for one bluebird box costs more than that!)
  • (David) Bamberger Ranch near Austin This 5500 acre ranch, once one of the worst pieces of land in the area, is being restored using sound ecological principles. They have received numerous awards, and do bus tours for up to 5000 “ecotourists” (including ranchers and school children) each year.
    • They had about 60 bluebird nestboxes, but many had enlarged entranced holes. Bluebirds do nest but they also may have wrens (no House Wrens in Central TX - maybe Bewick's or Carolina?) and House Sparrows (near animal feeding areas.) Unfortunately boxes are only monitored once per year (at the end, to ID nests) because of limited staffing (2 people plus a ranchhand). They marked the boxes: "Pink" called attention to a nestbox. "Green" indicated "EABL currently nesting." Of 60 nestboxes, only 4 had been occupied by bluebirds. (Another rancher mentioned he only got bluebirds on his place in areas with mowed grass.)
    • The guide indicated she thinks fire ants are helping control the local tick population.
    • They do participate in cowbird trapping. Cowbird parasitism can have a negative impact on the Golden-cheeked warbler populations.
    • Bamberger (who apparently is a bit of an eccentric) built the first man-made bat cave and does have a maternal free-tail bat colony and roosting. He made it wide enough so he could go in with a bulldozer to harvest guano, but right now ammonia levels are so high that respirators are needed.
    • He decided to turn the ranch into a non-profit. Since the land is assessed at $25 million, apparently his kids were not too happy about the decision. One is now on the Executive Board.
  • Doug and I went on a road trip to Balcones Canyonlands, a refuge for endangered Golden-cheeked Warbler and Black-capped Vireos (we heard but didn’t see the vireo). There are lots of Ash junipers (sometimes called red cedar) – the warblers use the bark strips to make nests.
  • Nestbox cams: wireless color nestbox cams can be purchased at, but you need a 12 V battery, 23 GHz transmitter, and receiver in the house, there can be interference, and they cost about $178. Doug and I made some with Birdhouse Spycams (black and white, 100 foot cable.) You can use a spade to dig a little trench for the cable. The volume is very sensitive. You may need to go back and re-focus the lens once the nest is built, depending on the height.
  • Idea hole depth may be 1 ¼ to 1 3/8". A hole deeper than 2.25” may result in hawk predation as it takes the birds a long time to get in and out. (Kridler)
  • Hybrid bluebirds are kind of marbled (Kridler)
  • Why don’t all nestboxes have 1 9/16” holes? Because the bits used to be more expensive or harder to find (now Chinese Forschner bids are reasonably priced), because of concerns about starlings adapting to smaller holes (as they have to crescent and batwing purple martin holes). (Kridler)
  • Why are MOBLs bigger than WEBLs or EABLs? They have a larger wingspan (hovering) so the wing muscles are bigger. I wondered if their lung capacity and thus rib cage are bigger because of high altitudes (less oxygen) – might be an interesting experiment to check House Sparrow lung sizes.
    • One person had a MOBL trail on a fence line in the prairie and has experienced zero predation.
    • When MOBL’s fledge, they huddle together on the ground if no trees are nearby.
  • Some people catch bumblebees and sell them to greenhouses for $2 apiece. A nestbox is really too small for them (they usually use mouse nests in the ground) as the colony will grow to about 400 bees by the fall. (Kridler) One guy got 2.5 lbs. of honey out of a box that had honeybees in it. Honeybees prefer wood duck boxes.
  • States where all three species nest include Montana, Colorado, and Alberta.
  • Infertile eggs: In one of Don Hutchings boxes, there were 5 broods of 5 eggs each (25 eggs total) in 2005, none of which hatched.
  • White eggs: One guy (Greg) had 25% white eggs one year, and then they tapered off. A WEBLer said he had only see one clutch of white eggs out of 300, a MOBLer said he only had1 clutch of white eggs out of 1200? (Note: the latest Bluebird Journal says that white eggs are the result of a recessive gene – is this a known fact?) See for more info on white eggs.
  • There was a FABULOUS talk on chimney swifts. I’ll post on that separately.
  • The NABS 2007 conference will be in Athens, GA, tentatively on September 20-23, 2007.
  • Quotes:
    • I’m not sure the bluebirds actually need us as much as we need them. The next generation needs something to be amazed by (Keith Kridler)
    • A homeowner will take better care of bluebirds in a backyard box than a trail manager ever could (Steve Garr)

"It’s a great day to put up a bluebird box"
- Steve Garr

HOME | Basics | Resources | House Sparrows | House Wrens | Nest/Egg ID | Site Map and Search | Suet Recipes | Tree Swallows | Contact me Bluebird Conservation

May all your blues be birds!

If you experience problems with the website/find broken links/have suggestions/corrections, please contact me!
The purpose of this site is to share information with anyone interested in bluebird conservation.
Feel free to link to it (preferred as I update content regularly), or use text from it for personal or educational purposes, with a link back to or a citation for the author.
No permission is granted for commercial use.
Appearance of automatically generated Google or other ads on this site does not constitute endorsement of any of those services or products!

Photo in header by Wendell Long.
© Original photographs are copyrighted, and may not be used without the express permission of the photographer. Please honor their copyright protection.
See disclaimer, necessitated by today's sadly litigious world.
Last updated March 24, 2016. Design by Chimalis.