There are six major components/accessories for this system.  The following describes the parts and function of each: 

1. SILO BODY

The silo body is made from six-inch diameter, thin-wall (schedule 30) PVC sewer pipe.  The ¼” diameter hole through the back of the silo is for mounting the silo to its support post in the field.  The bolt or screw inserted through this hole also serves as a “hanger pin” for the nest-inserts.  It is very important that the short polyethylene tubing (bushing) remain in place under the bolt head at all times.  The top is designed so that there are no fasteners (nails, screws, etc.) through the top, exterior surface, which reduces the possibility of roof leaks or corrosion of fasteners.  The roof is made from Sintra Plastic and is attached to the silo with PVC cement. 

2. VENT/ENTRANCE COVER

This device is a "sleeve" that is designed so it can be easily moved up and down on the exterior surface of the silo.  It has two major functions:  1. It can be moved up and down to adjust the size of the top air vents to accommodate temperature variations due to weather conditions.  During winter months, it should be positioned to fully close the air vents.  2.  The cover can be placed over the entrance hole to restrict birds from entering or exiting the silo.  When removing or replacing the vent/entrance cover on the silo, it is very important that it be slipped completely to the bottom of the silo.   If it is expanded far enough to exceed the silo’s outside diameter in order to remove it from the silo, its “springy-clamping” force may be stretched or diminished and allow it to slip down on the silo from gravitational pull. 

3. MOUNTING ADAPTER

The mounting adapter is the wood strip on the back of the silo.  The “V” shaped groove on both sides of this piece enable the round silo body to be attached to a variety of supports.  The side of the adapter toward the silo is cut so that there are no flat surfaces and it fits the silo body in a tight fashion.  The other side of the adapter is cut so that there is a small flat lip on either side of the “V”.  This feature allows the mounting adapter to be fastened securely to a round pipe/post or to be fastened to a flat surface.  If the silo is attached to a round post, only one fastener is necessary because the silo will not pivot on the single bolt.  If the silo is fastened to a flat surface, one should use a second fastener through the mounting adapter at its lower end (which extends beyond the silo body).  A second fastener will prevent the silo from pivoting when attached to a flat surface. 

4. NEST-INSERT

The nest-insert is a plastic bottle modified to serve as a removable nest container that can be easily placed into, or removed from, the silo.  The “hanger slot” in the back of the nest-insert provides support to the plastic bottle when it is inside the silo.  The hanger slot fits over the hanger bolt (described in #1 above).  This feature allows for quick, easy placement and removal of the insert without any tools. 

To remove the insert from the silo, grasp the bottom of the insert and gently lift up until it stops, then turn it counter clock-wise until it stops, then pull down and the insert will slip out of the silo.  Reverse the process to replace the insert in the silo.  Both the nest-insert and the trap-insert fit into the silo the same way. 

The bottom of the nest-insert (plastic bottle cap) has vent/drain holes in it.  During winter months, the vented bottom can be replaced with one without vents or the holes can be covered with a piece of thin material (poster board, heavy plastic, etc.) to reduce airflow. 

The top front of the plastic bottle has been cut away to provide access into the nest cavity for inspection/management purposes.  Landlord's with extremely large hands may prefer to cut away more of the top surface in order to get their hands inside during monitoring procedures.  This cut-away also provides the birds with access into the nest cavity and has a “ladder” below the entrance made from plastic gutter screen.  The ladder is attached to the nest-insert wall with silicone caulking.  After a period of extended use, the ladder may come loose from the nest-insert wall.  It can be re-cemented into place with silicone caulking. 

The “nest support screen” at the bottom of the nest-insert provides additional airflow and nest cooling during hot weather.  Some “bluebird experts” believe that a screened bottom may also aid in the removal of parasites from within the nest.  BB landlords are advised to provide enough nest material (pine needles, grass clippings etc.) to cover the screen before the nesting season. 

The nest-insert has a permanent visible mark on it to facilitate its alignment with the “hanger bolt” in the silo.  The mark is located at the front, bottom and exterior of the nest-insert.  It aids in the insert’s accurate placement into the silo by providing a visual point to be aligned with the “V” indentation mark on the bottom, front, exterior center of the silo when sliding the insert up into the silo. 

Nest-inserts should be inspected annually, and if there is any evidence of plastic deterioration, cracking or weakening, the insert should be replaced.  

5. TRAP-INSERT

The trap-insert fits into the silo the same way as the nest-insert and is simply another plastic bottle that has a smaller section cut away to allow for the placement of a Van Ert sparrow trap.  Once a House Sparrow has been trapped, it can easily be removed and disposed of by removing the entire trap-insert containing the entrapped sparrow.  When trap-inserts are used, it is very important that the site be observed frequently and any entrapped bird species be correctly identified.  Set the trap by extending a finger through the entrance hole and pushing the trap door in as far as it will go, and then lift up the treadle (by reaching up through the bottom of the insert with a second hand) until the trap door engages the treadle “hook.”   A “connecting rod” that extends through the bottom of the insert is a slight modification that enables setting the trap without removing the insert from the silo.  This feature is suggested for those landlords whose large hands will not fit through the access hole (bottle mouth) to set the trap.  If a “connecting rod” is needed, it can be easily fashioned from a coat hangar or long, slender piece of wood with a “Y” in the end of it to lift up on the treadle. 

6. INSERT HANGER

In the event that multiple Slippin' Silos are used on a single Bluebird trail, the “insert hanger” is designed to provide a place to position the the nest-insert outside of the silo during nest checks, allowing the landlord to have both hands free and still see the nest contents.  When ordering this item the user will be asked for  some dimensions (their height and the average height of their silo entrance holes) in order to construct a custom hanger suitable for the owner's requirements.

One end of the insert hanger is hooked into the entrance hole after the nest-insert has been removed from the silo.  The nest-insert can then be suspended from the opposite end of the insert hanger by hooking the hanger slot on the notch of the wooden dowel.