James R. Hill, III
Purple Martin Conservation Association
During the summer of 1998, martins in Texas suffered when daytime temperatures remained above 100 degrees Fahrenheit for more than 40 consecutive days. Desperate to save some of the nestlings that were jumping from houses or dying in the nests, landlords rigged misters above their housing, showered housing with hoses, or placed ice-packs next door to active compartments. For landlords with gourd colonies, adding ice packs was not an option. Adding a ventilation elbow, as described in this article, is something southern landlords may want to try.
The idea for adding a PVC ventilation elbow to gourds first came from Rocky Goforth of Smyrna, SC, in an article he wrote for Update 4(3):8-9, entitled: "Improving on a Gourd Thing." In that article, Rocky mentioned that one day in June of 1986, when the temperature at his place in South Carolina hit the high 90's, he lost 15 nestlings due to the extreme heat, as did other landlords in his area. According to Rocky, all of the natural gourds where the nestlings died were painted white, but they still got too hot for the martins, as any type of housing would with prolonged extreme heat prevailing. So he devised a way to increase the ventilation of a gourd without letting in any rainwater. What Rocky came up with was the use of a 90-degree PVC pipe joint (see photos).
|A plastic SuperGourd that has had a 1/2", schedule 40, PVC, 90-degree, ventilation elbow added to the backside of its upper neck.|
Materials: You will need one 1/2" schedule 40, 90-degree PVC pipe joint for each gourd you intend to modify. They are called 1/2," but their outer diameter is 1&1/16." You can buy a contractor's 10-pack for about $1.49 (or about 15¢ per elbow) at places like Home Depot, Builder's Square, Lowes, Value Home Center, or any local hardware store. Use a 1&1/8" hole saw with a built-in pilot bit (see upper left photo) to drill the hole in the gourd to receive the elbow. Drill the hole for the elbow in the upper neck of the gourd, directly in back where the PVC joint will be sloped down so water can't run in (see photos).
|A SuperGourd that has had a 1&1/8" hole drilled in its neck to receive the ventilation elbow.|
Attachment: Use white, paintable, 100% silicone caulking to attach the ventilation elbows to gourds. Put caulking around the hole and on the PVC pipe joint. Stick the pipe joint in the hole, make sure to seal all gaps, and smooth the caulking. These pipe vents can be plugged in early spring when cold drafts are more of a problem than excessive heat. Just remove the plugs once warm weather finally arrives.
|A back view of a SuperGourd equipped with a PVC ventilation elbow.|
As yet, no research has been conducted to test whether adding these vents to gourds will help increase nestling survival during periods of extreme heat. Nevertheless, the additional ventilation cannot hurt and may help prevent heat stress in nestlings.
Copyright 1999 by Purple Martin Conservation Association. All Rights Reserved.
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