BENBOX eastern bluebird nest box

June 27, 2007

The BENBOX is an eastern bluebird nest box that features a detachable nest cavity.  The detachable cavity slides in and out on rails like a drawer.  A 1 1/4” galvanized joist hanger nail on the right side serves as a locking pin.  A double roof is employed to reduce radiant heat absorption and to prolong the useful life of the nest box.  The inner roof is made of 3/4” thick wood and the outer roof is made of cement fiber (James Hardie cedarmill siding).  The outer roof is secured to the inner roof with polyurethane construction adhesive.  A 15 ga. plate steel hole guard protects the entrance hole from enlargement by woodpeckers and gnawing varmints.  “Flow through” ventilation is provided by including a rear horizontal slot vent at the same level as the entrance hole.  Good drainage is provided through floor corner cuts and a recessed center drain hole.  Mounting is facilitated by providing a 15/16” diameter hole in the center of the rear 2 X 4 cross member.  A 1/4” diameter bolt + wing nut can be used to secure the mounting pole in place.

BENBOX #1 06-27-2007

BENBOX front view

BENBOX #2 06-27-2007

BENBOX side view

BENBOX #3 06-27-2007

BENBOX open view

BENBOX #5 06-27-2007

BENBOX detachable nesting cavity showing horizontal slot vent

If you would like the bill-of-materials and plans for the BENBOX eastern bluebird nest box, send me an Email at Bluebird Shepherd.

If you have a specific topic you would like for me to discuss in a future article, Email me at the address shown above.

Bluebird Shepherd


SAFE eastern bluebird nest boxes

June 26, 2007

Most bluebird enthusiasts don’t build their own nest boxes.  They tend to buy them from their favorite wild song bird store, “big box” store, Farmers Market, or perhaps from a volunteer organization that produces low-cost nest boxes.

Regardless of where you obtain your bluebird nest box, the most important thing is to ensure the nest box is SAFE for bluebird habitation.

In order to be safely inhabited by eastern bluebirds, the nest box should have the following minimal characteristics.

– Correct entrance hole dimension.  A number of different entrance configurations are in use today.  Probably the most common configuration is a 1 1/2” diameter circular entrance hole.

– Correct nest cavity dimensions.  Although there is an ongoing somewhat “spirited” discussion regarding dimensions, most pundits would agree that a nest box with a 4” W X 4” L floor and 10″ H is adequate.  The inside height from the floor to the bottom of the entrance hole should be approximately 6”.  The Gilbertson style nest box is considerably smaller but is safe and attracts bluebirds.

The nest box should have provisions to allow it to be opened for monitoring and cleaning purposes.

Adequate ventilation should be provided to help ensure the safety of the birds during hot weather.

The North American Bluebird Society web site  provides detailed nest box specifications including dimensions for eastern bluebird nest boxes.

Quality of Construction (QOC) is very important. A number of volunteer organizations build nest boxes.  Unfortunately, some of these organizations concentrate on production volume and sacrifice quality of construction. The result is that some percentage of the nest boxes will be UNSAFE for bluebirds. One of the more common types of production problem is poor aim with a nail gun.  The digital photo included below shows a nest box produced by a volunteer organization that left two sharp nails protruding into the nesting cavity.  Obviously, a lack of quality assurance allowed this nest box to enter the marketplace.

scd-nest-boxes #1 06-25-2007

Sharp pointed nails protruding into the nesting chamber

Another common problem is unacceptably wide gaps between the access door and the sides of the nest box that allow rain water into the nesting chamber.  Wet nests from cold rains are potentially dangerous for bluebird eggs and young nestlings who have no capability to regulate their own temperatures.  Wet nests also tend to attract unwanted visitors such as ants and moisture seeking insects.   The digital photo included below shows the same nest box with the door closed.  Take note of the rather significant gap on the left side between the door and the side.

scd-nest-boxes #2 06-25-2007

Gap on left side of door that will allow rain water into the nest cavity

Although nest box entrance hole enlargement by woodpeckers and gnawing varmints isn’t a particularly common event, it does happen.  When it does, the result is a potentially unsafe nest box.  The enlarged entrance hole will allow larger aggressive bird species such as European Starlings to enter the nest box and harm the occupants.  The photo included below is the same nest box showing a 1/4” gap between the entrance hole and the metal flashing around it that serves as a hole guard. Woodpeckers and gnawing varmints have unobstructed access to the wood around the entrance hole.  One has to wonder why the organization that produced this nest box even bothered to include a hole guard.

scd-nest-boxes #3 06-25-2007

1/4” gap between hole guard and entrance hole

The “message” in this article is to always carefully examine every nest box you plan to acquire for defects and design flaws before you accept it.  If you find a significant defect in a nest box, be sure to bring it to the attention of the organization that produced it.

If you have a specific topic you would like for me to address in a future article, please Email me at Bluebird Shepherd.

Treat your Bluebirds

June 20, 2007

BB mealworms #1 06-23-2007

Male Eastern Bluebird preparing to transport mealworms

Bluebirds love mealworms!  Mealworms are the “filet mignon” meal for bluebirds.  Plan to provide mealworms for your bluebirds especially during the nestling stage of the nesting cycle.  This will help the adult bluebirds keep themselves fed and also facilitate feeding the nestlings.  Nestlings cannot digest the skins on mealworms during their first 3–4 days. The parents know this and will not feed them to the nestlings.  After the 4th day, the parents will feed mealworms to the nestlings.

Mealworms can be purchased from most wild song bird supply stores and through the Internet.  You can do a Google search on mealworms to locate Internet suppliers.  Mealworms need to be kept refrigerated.

BB mealworms #1a 06-23-2007

Male bluebird heading into the nest box with mealworms

The bluebird parents will take turns ferrying the mealworms to the hungry nestlings.  While the female bluebird is brooding the clutch, the male will feed her through the nest box entrance hole.

BB mealworms #2 06-23-2007

Male bluebird feeding mealworms to hungry nestlings

If you have a specific topic that you would like for me to address in a future article, please Email me at Bluebird Shepherd.

Simple Steps

June 17, 2007

There are a number of simple steps you can take in your yard to help protect your feathery friends from the neighborhood marauder — yes, somebody’s prized cat that is let out of the house to roam yards and hone its natural hunting skills by preying on wild song birds.

Step #1 – If you can identify the owners of the cat, contact them and remind them of local, county, and state ordinances dealing with unleashed pets.  Make a direct appeal to the owners to keep the pet out of your yard at all times or you will contact the Animal Control Authorities and report the next incident.  A digital photo of the cat in your yard around nest boxes, feeders, and bird baths is usually sufficient proof for the owners as well as Animal Control Officers.

Step #2 – If the owners continues to allow the pet to roam freely, contact Animal Control, report the situation, and request the use of a small animal trap.  These types of traps are very effective and will not harm trapped animals.  Unfortunately, the trap will close when the trigger plate is depressed regardless of who or what tripped it.  You may wind up having trapped the cat, a possum, or a curious black bird. If you trapped a mystery visitor and need to translocate it a new habitat,  contact your local or state Wildlife Resources organizations for designated locations.

If you did trap the cat, call Animal Control for pickup and processing.  Many pet cats have microchip implants in their shoulders that can be scanned for identification purposes.  In some cases, the cat may be wearing an ID tag.  Many local ordinances allow the owners, upon proper pet identification, to reclaim it after paying a fine.  The ordinances include progressively larger fines for repeat violations.

Step #3 – Placement of nest boxes, feeders, and bird baths can drastically affect the safety of wild birds.  If nest boxes, feeders and bird baths are located too near thick bushes or shrubs, the marauding cat can lie under them out of sight and attack quickly enough to snare a bird.  Shrubs and bushes tend to grow over time.  Some of them quite rapidly.  You should frequently assess the “threat potential” posed to birds by growth patterns.  Either prune the shrub/bush or relocate the nest box/feeder/bird bath to provide safe zones of open area around them.

If your marauder is a particularly aggressive cat,  you may have to resort to using low poultry wire perimeters around the closest shrubs and bushes to deter the unwanted hunter.

Step #4 (optional) – I have developed a portable mounting system comprised of a concrete base and utilizing threaded galvanized pipe.  The base is heavy enough to be completely stable yet light enough to be easily relocated.  I use quick-setting concrete that can be dyed to match specific decors.  The galvanized metal pipe can be spray painted as needed to match decors.

By using the portable mounting system, I have the flexibility to place nest boxes, feeders, and bird baths where they are accessible and safe for wild bird use.

Portable mounting system

Portable Mounting System

I hope you found this article useful.  If you would like a copy of the plans, bill of materials, and instructions for the portable mounting system, feel free to Email me at Bluebird Shepherd.

If you have a specific area of interest that you would like for me to concentrate on in a future article, please Email me at the address shown above.

BLOG Introduction

June 13, 2007



This article is a brief introduction regarding the purpose of the BLOG. 

The purpose of this BLOG is to provide useful articles related to bluebird conservation.  The BLOG is an adjunct to  — a website dedicated to bluebird conservation.  As it matures, the website will serve as a 24 X 7 searchable repository containing plans for DIY projects, FAQs, bluebird education support packages for presenters, research reports, and numerous other elements focusing on bluebird conservation.

I don’t claim to be a bluebird expert although I have met some folks who are.  My only claim is that I’m an experienced and avid bluebirder thoroughly dedicated to bluebird conservation.

My special interest is designing and building experimental bluebird nest boxes.  I enjoy using new materials as they become available in the marketplace.  Wherever possible, I make it a point to use OTS (off-the-shelf) items available to everyone.

If you have a specific topic you would like for me to address in a future article, please Email me the details at

Feel free to contact me at the same Email address if you have specific questions regarding bluebird conservation.  I will do my best to answer them.

I hope you will visit again soon.  I plan to post the next article shortly.