Friday, November 13, 2009

A Seed-Catcher for Pole-Mounted Bird Feeders

We have two "shepherd's crook" type poles supporting bird feeders in our yard. The one in the back yard (shown below) provides sunflower seed, and the one on the east side of the house provides nyger seed. I have tried various methods of dealing with the seed hulls and uneaten seed that falls below the feeders, but I think the new seed-catchers that I have designed and built are the best solution. I am providing the design details here for the many other birdwatchers that have pole-mounted feeders.

From Seed Catcher Project

The Problem:

Among the seed hulls that fall to the ground are uneaten seeds or fragments, which attract mice and rats. Also attracted are ground feeders such as pigeons, grackles, and starlings, which because of their mobbing behavior tends to frighten away the more desirable songbirds. A screen a few inches above the ground with a mesh large enough to allow the seed to fall through will deter the ground feeders. But the mesh must be smaller than one inch and the sides also enclosed securely to prevent small birds from being trapped inside. However, to deter rodents from tunneling into the enclosure, the bottom must also be secured. The bottom must also allow rainwater to pass through. Also, there is the problem of how to dispose of the fallen seed when the enclosure becomes full of old seed.

My seed-catcher design solves all of these problems, using two 3-by-5 foot wooden frames that fit on either side of the pole, covering a 6-by-5 foot area. Notches on one side of each frame allow the frames to fit snugly around the pole. Hardware cloth with a half-inch grid covering the top and bottom of each frame allows seed to fall through while excluding ground-feeding birds and rodents. Above the bottom hardware cloth is a sheet of porous plastic that prevents seed from falling through the bottom onto the ground or into a rodent tunnel, but allows rainwater to drain. The fabric/plastic sold as "weed stop" fabric for use under stone or mulch beds works well here. Both hardware cloth and weed-stop fabric are available in 36-inch wide rolls.

At the center front of the pair of frames, extra boards closely spaced will support you when you need to refill the feeders, but old seed can fall between these boards.

To dispose of the old seed, turn each frame over, dumping the old seed onto a tarp or plastic sheet. Then, folding the sheet in half, you can dump the sheet into a waste container. No shoveling or sweeping of the ground is needed.

Materials List:

6 8-foot lengths of "1-by-4" inch lumber (actually 3/4" by 3 1/2")
4 pieces of 36 inch by 5 foot hardware cloth, with 1/2 inch mesh
10 feet of "weed-stop" fabric, 36 inches wide
64 wood screws, 1 1/2 inches long, (1 box, Philips head recommended)
about 150 galvanized staples, 1 inch long (1 box)
about 15 to 20 feet of tape that can stick to plastic and wood.

The "weed-stop" fabric may be called by other names. It is a porous plastic or fabric intended for use under stone beds, paving stones, or mulch to allow rain water to drain while preventing weeds from penetrating.

Cutting list for the six 8-ft lengths of "1-by-4" lumber:

Each line lists the cuts for one 8-ft board:

60" + 34 1/2"
60" + 34 1/2"
29" + 29" + 34 1/2"
29" + 29" + 34 1/2"
24" + 24" + 24" + 24"
24" + 24" + 34 1/2" + 6 3/4" + 6 3/4"

Save two pieces of scrap for temporary use.

The last 34 1/2" piece should be rip-cut in half lengthwise, so that each half will be about 1 3/4" wide.

The two 6 3/4" pieces don't need to be exactly that length. Just cut the remainder in half, and they will be about 6 3/4" each.

Recommended tools:

tape measure
carpenter's pencil
circular power saw
1 or 2 corner clamps (holds 2 pieces at right angles)
battery-powered drill
battery-powered screw driver
(two power drill/drivers saves changing bits)
drill bit, size to match shank of screws
scissors or knife (to cut tape)
tin snips (heavy-duty scissors for sheet metal, to cut hardware cloth)

From Seed Catcher Project


All of the following diagrams show edge-on views of the lumber. They are not exactly to scale. (The thickness of the lumber is somewhat exaggerated.)

Predrill holes for all screws using a drill bit that matches the diameter of the solid center of the screw. I hold a screw and the drill bit parallel to each other up to the light to check that the drill bit does not obscure the threads of the screw.

Align two 29" pieces over a 60" piece, supported by the 6 3/4" piece and two scrap pieces as shown, centering the 6 3/4" piece under the 2" gap. Fasten the 29" pieces to the 60" piece with 2 screws on each side of the gap. This makes a 60" side with a notch at the center. If the screws go in too far, they may attach slightly to the 60" piece. If this happens, pry them apart with a screwdriver. Be careful of the protruding screw points when handling; but these points will end up inside the finished frame where they will be harmless. Make two notched sides like this.
From Seed Catcher Project

Next, assemble a basic frame using a notched 60" side, a one-piece 60" side, and two 34 1/2" end pieces. Be sure the notch is facing outward. A corner clamp is useful for holding two pieces together at each corner while drilling and screwing. Use 3 screws at each corner. Make two frames like this.
From Seed Catcher Project

Three 24" pieces are added to each frame to create an area that will support you when you refill the feeders. Space these 4 inches apart (3 3/4" between boards), starting at the notched side. Fasten with 3 screws each. Do two frames as shown.
From Seed Catcher Project

The frames are identical until the pieces shown in blue in the next diagram are added. These narrow pieces come from a 34 1/2" length of 1x4 lumber that is cut in half lengthwise. Orient the frames with the notched sides facing each other as shown. (When pushed together, the two frames will wrap around the pole at the notches.)

First. hold each narrow piece over the side where the 24" pieces are fastened, and copy the spacing onto the narrow piece. Then fasten each narrow piece to the free ends of the 24" pieces at the top of the frame so seed can pass below it. Use one screw for each piece. Last, fasten the ends of each narrow piece to the long sides, using one screw at each end. The frames are now mirror images of each other, and the narrow pieces mark the top side of each frame.
From Seed Catcher Project

Cover the bottom of each frame with a 3 by 5 ft piece of porous "weed-stop" plastic, holding in place with pieces of tape about six inches apart all around. Then cover with a 3 by 5 ft piece of hardware cloth as follows. First, un-roll the hardware cloth so that it is nearly flat, or slightly curled. (I sit with the roll in my lap and push the hardware cloth over my knees, working from side to side and gradually toward the other end, with the semi-flattened part extending away from me.) Anchor one corner of the hardware cloth to one corner of the frame with a screw (a washer on the screw helps), with the hardware cloth curling upward, then stretch out the hardware cloth and anchor the opposite corner in the same manner. Then anchor the remaining two corners. Check that the hardware cloth fits the long sides well; it can over-shoot the short sides at first.

Fasten the hardware cloth along the long sides, except for the corners, using 1-inch staples about six inches apart. (The staples also hold the "weed-stop" plastic in place, so the tape was needed only temporarily.) Next, remove the anchor screws and trim the ends of the hardware cloth with tin snips, cutting next to a parallel wire to avoid making sharp points. Staple the short ends. If any hardware cloth protrudes past the edge of the frame, use a hammer to bend the hardware cloth down over the edge. First angle the hammer to bend it half-way, then make another pass over it to bend it all the way.

Cover the top with only hardware cloth, in the same manner.