Starling Resistant Entrance Holes or SREH have helped countless Purple Martins from falling victim to European Starlings. They are not without risks. Scroll down for a picture of wing entrapment. There are several entrance options available on the market today. Some of which are protected by patents and copyrights.
Crescent Starling Resistant Entrance Hole (SREH) is openly available to any that wish to use it. As with all SREH, the dimensions are crucial as too large by a hair will allow Starlings entrance. The Purple Martin community owes a debt of gratitude to Mr. Charles McEwen for developing this entrance. No SREH (to date) is 100% starling proof.
PurpleMartins-R-Us.com does sell some commercially available entrance plates for pre-manufactured housing such as Trio houses. We highly recommend www.entrancesbysandy.com for entrance plates that can be fit on any type of housing either store bought or self made.
Please be aware that having SREH increases the chances of Wing Entrapment. (Scroll down to see an example)
If unnoticed, wing entrapment can lead to the death of The bird.
Wing Entrapment occurs when a purple martin fighting inside a compartment with another martin will lean on the inner portion of the door and the birds wing exits before the bird. The bird is then stuck and may not be able to remove itself. The birds inside the compartment will die of heat exhaustion if not removed promptly.
Walking around your housing twice a day is suggested, at the very least one should always keep an eye out for this event.