How to Convert Gourds with Round Holes to Starling-resistant Crescents

Reprinted from: Purple Martin Update 9(4): 1
Chuck Abare
17835 Oakdale Rd
Athens, AL 35613

Materials required
(all items available at K-Mart or Wal-Mart):

• Some Polypropylene. (I used a rectangular white wastebasket. Try to get one that is about 1/16" thick.)
• A sharp utility knife
• A bunch of #6 x 1/2" Phillips pan head self-tapping sheet metal screws (usually sold 100 to a pack)
• 1/16" and 1/8" drill bits and a drill
• A small “keyhole” saw or jigsaw
• A small wood rasp
• A flexible straight edge (I used a 6" piece of plastic)
• A pair of safety glasses
• A short ruler that has graduations of 1/16"
• Paintable white latex caulking, (optional)
• A small flat paint brush (If you use caulking)

Fig. 1: First, you have to obtain some material for the SREH add-on’s. A white wastebasket from your local Wal-Mart or K-mart will do just fine. These are usually made from Polypropylene and if you get one that is somewhat square and with material about 1/16" thick, then it will work just fine. The material can be cut and worked with a good sharp utility knife. A thin permanent marking pen works good to draw all your lines with. Here’s how I did mine:

First, a “very accurate” pattern of a crescent-shaped SREH will have to be made. (Use the drawing shown on page 8, expanded to the correct size.) I made mine from a piece of 1/8" Lexan that I had on hand. One can also be made from a piece of just about any stable plastic that you might have sitting around. Take your time making it. It has to be accurate since it will be the pattern for all your add-on’s. If it’s too big, the starlings can get in, and if it’s too small, the martins can’t.

Next, I laid the pattern on my wastebasket and cut it out simply by tracing it using the utility knife. Tracing with a Sharpie and then cutting along the lines works just as well. It may help a lot if you cut all the large flat portions out of your wastebasket so you can lay them flat. Now, I drilled the 1/8" holes in my add-on to screw it onto my gourds. (One in each of the four corners approximately as shown.)

Photo 2: Gourd preparation: Take a gourd that has a round hole in it. Lay your flexible straight edge even with the bottom of the hole so that it will be parallel with the ground when the gourd is hanging. Using a sharp pencil, draw a horizontal line, even with the bottom of the round hole. About three inches either side of the hole will be plenty long enough.

Photo 3: Now, lay your freshly cut out “add-on” over the hole with the bottom of the piece setting on the horizontal line and trace the inside curvature of the crescent onto the gourd. Only part of it will actually be on the gourd, the rest is hole. Using a jigsaw or even a small keyhole saw, start at the hole and work your way out in both directions being very careful to keep the line very straight. Next, remove the part of the gourd that you drew the line around, shown as crosshatched in the photo.

Once the material has been removed, lay your SREH “add-on” onto the gourd, centered over the hole, with the bottom setting exactly on the horizontal line you cut. Predrill a 1/16" hole in the gourd where the right bottom screw hole is in the pattern. Add a #6 x 1/2" long Phillips self-threading screw. Now that one screw is in place, you can maneuver the piece around more easily. Level the other side of the piece to the horizontal cut. Before screwing in place, use the scale and check your measurement, ensuring it is 1&3/16". Holding the piece in place, predrill and add the left bottom screw. Complete the assembly by predrilling and adding the two top screws. Double-check your opening dimension. Now, using your utility knife, clean up any edges of the gourd near the half-moon so that the crescent is accurate.

Photo 4: The finished edition should look like the photo here. The reason I left the bottom of the add-on piece open was that I wanted the martins to have natural gourd surface for their feet to land on and cling to. Just my own little quirk, but I feel they like the feel of natural better. The add-on’s open bottom also makes it easier to add it to a spherical surface.

Photo 5: Next, I added latex caulking all around the SREH (Wal-Mart brand; white, 15 year, with no added silicone, so it dries faster.) I just think it gives a better finished look. Apply the caulking and then with a small paint brush, smooth it out to make it look good. I even put a little under the hole for their feet to grab onto. Then, let it dry overnight. The finished gourd with a starling-resistant 1&3/16" crescent SREH is shown in photo 5, after caulking and painting.

Putting Crescents in Commercial Plastic Gourds
As of late, some plastic gourds have made their introduction to the martin market. Both of these can be worked to include the crescent SREH. Natureline plastic gourds: You can purchase a solid door blank and then cut the crescent into it. It really isn’t that hard. Most of the material can be drilled away using a 3/8" drill and then use a utility knife to trim away the rest to form the crescent. (Not shown here; use same technique as for new natural gourds.)

Photo 6: SuperGourd plastic gourds: The same technique can be used to add the crescent as was used on the round-hole natural gourds. It works exactly the same and the birds hardly even notice. The caulking doesn’t stick to plastic very well, but if the job is done neatly, it really isn’t needed. You will also need to trim away some material at the upper corners of the add-on, so that the add-on, itself, fits up under the SuperGourd’s canopy.

These crescent SREH’s are something I feel are very important. Starlings have become such a problem in some places and of course, the average landlord can’t sit around all day keeping watch on his or her colony site. With the employment of these SREH’s, 99.9% of your starling problems will be eliminated, and I personally enjoy sitting back and watching my martins go in and out of their gourds, free from starling harassment.

One last thing, if you don’t want to spend the time making the “add-on’s” from plastic Styrene, Frank Prekup ( has a die that punches templates with crescent-shaped SREH’s out of thin aluminum. They are very accurate and these would work just as well as the plastic add-on’s. The caulking would fill all around it and make it work just like my plastic versions.

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