Squirrel Proof Bird Feeder

The perch on this bird feeder will hold up a light bird, but will drop down when a squirrel uses it -- making it very difficult for the squirrel to get the food.

I used the following parts for my build:

• 3" diameter plumbing pipe (about 1.5' long). I used white pcv pipe
• Pipe cap to match plumbing pipe
• 1" diameter plumbing pipe (less than 1' long). (Slightly larger would work)
• Solvent glue (of type to match plumbing pipe)
• 8 screws (I used #8 * 3/4")
• 1 bolt-eye with matching nut
• 1 * 4 (4")
• 2 small screw eyes
• picture wire (about 1')
• Fishing line (about 4', the heavier the better)
• Fishing weight - 4 oz
• Rope to hang feeder with (I used 1/4")
• Willow -- from the forest (about 3', about 1/3" diameter)
• Bird food

I used the following tools:

• Miter saw
• Drill with the following bits:
  • 1/16" (for pilot holes)
  • 1/8" (for screw holes)
  • 1/4" (for eye bolt)
  • 7/8" spade (for food holes)
  • screwdriver bit (because I am too lazy to use a screwdriver.)
• Jigsaw
• Moto-tool (to make bayonet holes in pipe cap.) If you don't have one you could:
  • Get one. Off brand ones are often just $20, and they are very useful.
  • Use hand tools such as a coping saw.
  • Not use the bayonet, but take out screws to re-load the bird seed.
• Pliers (to bend the picture wire with.)
• Pencil or fine tipped felt pen

I use a bayonet style mount so that I can remove the top cap easily to re-load the feeder with food. This is not mandatory, you can just pop screws through the cap and pipe. When you want to re-load the feeder, just remove the screws.

Mounting the eye:

Ok, a bit easy. Drill a hole, pop the eye bolt through, put the nut on.

Making the bayonet slots:

Make 4 bayonet slots in the top cap as pictured. To do this, I marked the slot shape with a felt pen, and used my trusty moto-tool. Making these slots perfectly symmetrical is not necessary. In fact, it is convenient to have one slot quite clearly not symmetrical to figure out the alignment. Another option is to put alignment marks on both the main pipe and the cap with a felt pen.

Mounting the screws:

Place the cap loosely on the top of the pipe. Mark the pipe at each slot, in the loose position. Drill main pipe at the mark with a pilot-sized hole (small enough that the threads will bite.) Put the screws in while the the cap is still on. Leave them quite loose. Now you should be able to twist the cap to make it bayonet on, or pull it to take the cap off.

• Cut a small ring out of the main pipe material (1" thick is lots)
• Place this ring on the 1 * 4
• Draw the inside diameter of the main pipe material onto the 1 * 4.
• Cut out the resultant circle with a jigsaw. The 1 * 4 can be a wee bit small, but can't be too big, or it won't fit into the main pipe
• Mount one of the small screw eyes into the center of the bottom cap.
• Mount the other small screw eye about an inch off center. Make the holes face each other so that a bolt could be pushed between both of them.
• Determine how far into the main pipe the bottom cap must go. If the screw eyes stick out of the end cap by 1/2 inch, then the bottom cap must be indented into the main pipe by at least 1/2 inch. The 1 * 4 is about 3/4" thick, so in this case the screws will be about 5/8 inches in(1/2" + (3/4" / 2)). The bottom of the feed holes should be 1 1/4" (1/2" + 3/4") in.
  • It is much better to have the bottom cap too deep into the main tube than too shallow. If I were to do it again, I'd make mine 1/2" deeper in.

The main tube must be long enough that a squirrel can't clamp his hind feet to the top cap, and reach down to get to the food. The taller, the more food it holds.

Making the food holes:

I drilled 4 holes in my tube with the 7/8" spade bit. The placement of these holes is really quite important.. The bottom cap must be placed inside the main pipe sufficiently far that the eyes are completely covered by the cap. If you don't do this your perch will be unstable! The feed holes need to be completely above the bottom cap, or the bottom cap will cover them up.

The more symmetrical these holes are around the tube, the prettier your feeder will be, but if it ain't perfect, it'll still work just fine.

If you use a spade bit as I did, when you drill these holes, you will find that the hole is of very poor quality. They are not visible, so it doesn't matter much, but I cleaned up my holes with my moto-tool.

Mounting the bottom cap:

Drill 4 holes (using the bit which allows the screws to fit through without turning) such that they will go approximately into the middle of the bottom cap. (Remember that the bottom cap is pushed into the tube sufficiently. These holes need not be symmetrical, in fact if they are clearly not symmetrical, it'll be easier to figure out the orientation of the bottom cap if you ever remove it.

Place the bottom cap into place, and drill pilot holes through the 4 holes in the pipe. Put in the screws. If you ever want to remove the bottom cap (probably unnecessary) mark the inside of the main pipe, and the bottom of the bottom cap with an alignment mark. Otherwise getting the alignment of your pilot holes right will be a pain.

The seed cups are very necessary! You will find that if you don't use seed cups, your bird food will filter right through the feed holes. Making smaller holes doesn't help much. As the birds pull out a bit of feed, a bunch pours out behind it.

To make the seed cups, I used my chop saw. I cut a 2 * 6 to a 45 degree angle as a support. I then set the saw to a 22 degree angle. I cut so that the wide end of the seed cup was about a half-pipe. I tried to set this up as a jig to get each seed cup exactly the same size for appearance sake.

Placing the seed cups: I placed the top of the seed cup at the top of each hole. That worked just fine.

Mounting the seed cups: I thought about shaping the edge of the seed cups so that I could get good surface contact between them and the pipe. That proved to be prohibitively difficult. Instead I used the following 2 step process:

• I applied solvent glue to the edge of the seed cup, and put it into place to dry.
• I then made a paste by mixing solvent glue with the plumbing pipe sawdust. I applied this paste to the inside of the seed cup to weld it to the main pipe. The feed hole proved very useful in getting the glue in the right place. This seems quite strong.

Note: If I were to make the bird feeder again, I would make the seed cups larger, as the birds had some trouble getting to the food.

• Cut two pieces of willow about 7" long
• Tie them together with the picture wire at the middle to make an X
• Make a ring of willow that is small enough to mount to all 4 legs of the X, support it with picture wire.
• Tie this ring onto each leg of the X with picture wire. (The ring should sit on top of the X, not hung from the bottom.)
• Consider the lower of the two pieces that make the X:
  • Cut two pieces of willow the length between the upper member and the outside ring.
  • Tie these two pieces to the top of the lower piece. This will make a flat surface that will bump against the bottom of the main pipe. If you don't do this, the perch will be unstable, and easily wiggle.
• Make a ring on one leg of the X, about the same distance from the middle as the two eyes are separated in the bottom cap. (This system with the two eyes, and the guide hole in the perch stops all manner of line tangling issues!)

The fishing line should be about 3 - 4' long. The perch will only slide half-way down it because of the loop in the perch. It must be long enough that a squirrel can't use the stopped perch as a base to reach up to the food.

• Tie fishing line to the center of the perch
• Run the fishing line through the center eye, then the off-center eye of the bottom cap
• Run the fishing line through the wire loop created in the perch.
• Tie the fishing weight onto the line. You may want to tie in a snap swivel.

Oh, on the size of the fishing weight -- I looked up squirrels in Wikipedia. It said that a small one was about 8 ounces. That's why I chose a 4 oz weight. A much smaller weight doesn't work anyway as it doesn't overcome friction to lift the perch. If you have a particularly large variety of squirrel, you may be able to use a bigger weight. If you have a smaller squirrel, you may have to use pulleys instead of eyes on the bottom cap to overcome the friction, allowing you to use a smaller weight.

I had a latch gizmo that I tied to the tree, but you could just tie a loop of rope to the tree. I tied the rope to the eye bolt in the top cap, and threaded the rope through the loop in the tree branch. I was then able to pull the bird feeder (full of feed, of course) up into the tree, and tie the rope off near the bottom of the tree. I needed to use a ladder to get that first loop into place, but from that point on, I can access my bird feeder from the ground.