What is a predator guard and why is it important?
A predator guard is a simple device that keeps raccoons, snakes, and other ground predators from being able to climb your pole and eat your martins and their nestlings. While there are many different styles, the most effective is a stovepipe-shaped baffle, mounted at least 4 feet off the ground. You can also use an electric guard. Snakes and raccoons are found throughout the state of NC. Every martin pole needs a predator guard. Click here to read more about predator guards.
Why do I have to use a predator guard? I never see any snakes or raccoons. I keep my grass mowed short. Can’t I just kill any snake I see? Can I rely on my dog/cats/donkeys/etc to kill snakes in my area?
No, you still need a predator guard. This can be a stovepipe-type guard or an electric guard. Snakes and raccoons often come at night when we are sleeping. Snakes are an important part of the ecosystem and killing them is not only unethical, it’s no guarantee that another one won’t appear later. It’s best to prevent one from gaining access to your pole in the first place and use a predator guard.
I had a predator guard, but a snake or raccoon still ate my martins. What went wrong?
You may have had the guard mounted too low (less than 4 ft off the ground), or too close to a winch box underneath it, or the guard may have been too small. Guards should be at least 24 inches long (longer is better) and at least 8 inches in diameter and not have any rough protrusions on the outside of them. Cables or ropes should run up the inside of them. When in doubt, mount it high and build (or buy) the biggest one you can get. Wax the outside of the guard, and as a backup method of protection, you can secure a wad of fluffed-out bird netting over the top of the guard to stop any snake that manages to bypass the guard. Just remember that netting is a trap, and you must be willing to monitor it daily and release any snake that gets caught in it. If you do not want to handle any snakes, consider changing your guard type, or install an electric guard.
What does SREH mean?
SREH= Starling resistant entrance hole. Pictures are available on this page.
I have always used round holes, and I don’t want to use SREH. The holes look weird and I don’t think martins can fit in those half-moon shapes. What can I do?
SREH are made to exclude starlings, which are classified as non-native, invasive birds that can and will kill martins, throw out their eggs, and kill their nestlings. You need to protect your martins from starlings. If you don’t want to use SREH, you should trap or shoot the starlings. Martins cannot fight off a starling inside their nest. The starling can easily kill a martin and this is why it's important to protect your martins. There are different styles of SREH. It’s important to make sure the porch is mounted no more than 1/4” under the bottom of the crescent or other SREH. This will keep the starling from using its long legs to push its way into the entrance. Sometimes after converting your holes to SREH, martins will peek in and may shimmy halfway in and then back out. This is normal behavior when they are first investigating the change and they will soon go in, provided the SREH is the correct size. If you decide to cut one yourself, pay close attention to the dimensions.
Do starlings and house sparrows really cause a problem for martins? They seem to cohabitate just fine in my martin house/gourds and they leave each other alone. Why should I start eliminating them now?
This is a common comment from folks that do not do nest checks and are not aware of the danger those species pose. House sparrows and starlings are classified as non-native, invasive species. Both house sparrows and starlings will take over and destroy martin nests. Even if a martin chases a house sparrow or starling away from its nest, the invasive species will typically come right back, which can be when the martin landlord is not looking, and they will do their dirty work when the martins are out feeding. Martins that live in housing infested with house sparrows or starlings often fledge less young per nest, or none at all. You need to decide if your martin housing is going to raise invasive species or the native purple martin. The population of the purple martin has decreased 25% since the 1970s, so what you do at your colony site matters. Still not sure? Watch this teaching video for more information.
Can't I just pull the sparrow nests out? Won't that make them go away? I don't like the idea of killing one bird to help another one.
This 'pulling nest' method is called passive management. It rarely works and often causes more problems. House sparrows are extremely tenacious and will often fly right down to the pulled nest material and put it right back into their chosen cavity. In addition, pulling their nest often makes them even more aggressive towards purple martins (or any other species) trying to nest near them. The best solution is to humanely euthanize the house sparrows, which is legal in NC (and most areas of the country). If they have already built a nest, trap or shoot them first, and then completely remove the house sparrow nest. If you have a high population of house sparrows, it may take a while to clear your property, but they have a relatively small home range and long-term control is possible if the landlord keeps at it all season long. For more information on humane euthanasia for HOSP and EUST, see this page.
My martin housing has round holes. What do I do now?
Convert them to SREH. You can use SREH plates, SREH tunnels, or cut one yourself using the guide on this page. It’s important to enlarge compartments on houses using SREH, if your compartments were originally 6”x6”. You can do this by knocking out an adjacent wall on a house to make them 6”x12”.
I have a bluebird, tree swallow, great-crested flycatcher, or other native bird nesting in my martin house or gourd rack. Will this be a problem for the martins?
Yes, this is especially a problem if you do NOT have an established site. Do not allow any other bird species to nest in your martin housing. If a native bird is trying to build a nest in your martin housing, close it off and put up separate housing for the bird in question. If you are having trouble getting tree swallows to accept a bluebird house on its own pole, try hanging a white gourd on a separate pole for them instead. For full directions, see the trihabitation protocol here. If a tree swallow tries to move into a gourd rack that is already partially occupied by martins, hang a separate gourd for them near the gourd rack. Oftentimes, the martins will run them away from the rack, and they will then quickly take to the gourd you have set up for them. Alternatively, you can move their gourd off the rack onto its own pole/shepherd’s hook after they have laid 1 egg in it, and then put up a new gourd in the place where the tree swallow’s gourd was hanging. This procedure is also covered in the trihabitation protocol linked above.
I have a hawk trying to eat my martins, or an owl is attacking them. What can I do?
First of all, be aware that it is illegal to shoot birds of prey, so you must use non-lethal deterrence methods. This includes the use of decoys (rotate daily if possible), a dancing man, clapping two long boards together to make a loud noise, an airhorn, or caging around the housing. Tunnels on gourds will NOT protect martins from owls; the owl simply has to beat the gourd with its wings or grab the gourd and shake it in order to flush the martins into its waiting talons. You can see a video on how to build an effective cage here.