Rat Snake Predation On Purple Martin Colonies

[Steve Kroenke]

Rat Snake Predation On Purple Martin Colonies

Rat snakes are significant predators of purple martins and there are a number of different species, including the black, gray, and corn (red). These snakes are widely distributed throughout the United States with the largest concentrations in the Deep South. Rat snakes live in most regions where martins nest, though the upper mid-west and northeast of the United States and all of Canada have a much smaller snake population.

All these snakes are powerful constrictors, can be quite long, and are somewhat like miniature pythons/boas. These snakes are designed to suffocate their prey with strong, unyielding constrictions. They coil around their victim and each time the prey exhales, the coil is tightened. Eventually the prey is suffocated and then swallowed, usually head first. Though their name implies rat hunter, these snakes are formidable hunters of both cavity and non-cavity nesting birds. It makes no difference if the prey has fur or feathers--it is warm blooded and that is what counts.

Rat snakes raid numerous purple martin colonies each year and many of their depredations go unnoticed until it is too late. These snakes often hunt at night and this significantly reduces the chances that a martin landlord would see one crawling near his/her colony. Unfortunately the vast majority of purple martin house/gourd poles offer no protection from these predators. Many landlords do not believe that these snakes are living in well-maintained yards or in suburbia, or that they can climb metal poles. I once talked myself red in the face with a lady who finally said, Why young man, no snake can climb these metal poles! She actually scolded me! These landlords are mistaken, as rat snakes are very common, particularly in the Deep South, and they CAN easily climb metal poles. All purple martin landlords need to beware of the belly crawlers and how these formidable predators find and raid martin colonies.

How Do Rat Snakes Find And Raid Purple Martin Colonies

They don’t need sight nor do they need sound. They don’t need great speed. They don’t need a hunter’s moon in the dead of night and they can find their way in total darkness. The rat snake has a secret biological weapon that would rival the most sophisticated radar tracking system known to mankind. It is called the Jacobson’s organ and is located in the roof of the snake’s mouth. It is basically an olfactory global positioning system and is highly sensitive to molecules of warm-blooded scent. Rat snakes are scaly blood hounds as they sniff the air with their flickering tongues. The molecule-laden tongue is transferred to the Jacobson’s organ in the roof of their mouths. Once these snakes detect the scent of a possible meal, the hunt begins and their sensors guide them to their victim(s). They are relentless in their silent pursuit and follow the scent like a wolf on the trail of a deer. Their prey can be as little as five feet off the ground in a bluebird house to 30 or more feet high up a tree in an open bird’s nest. And nothing is more inviting and tempting than a purple martin house or gourd cluster filled with adult and baby purple martins. Such a large concentration of available prey fills the air with its scent that disburses widely into nearby thickets, overgrown lawns, trees…places where a rat snake may be crawling or hiding and sniffing the air.

A martin colony filled with adult and young birds is a feeding bonanza to any hungry rat snake. The martins, sleeping in their houses/gourds, are totally unaware of the slithering horror that is crawling toward them. Once the snake reaches the base of the martin house pole, the snake begins its ascent. By now the air is thick with martin scent and the snake’s tongue flickers in and out, tasting its forthcoming meal. Slowly, inexorably, the snake propels itself upward in a corkscrew maneuver, using its powerful coils to constrict itself forward up the pole. The martins are totally oblivious to the approaching danger as the snake makes no sound nor produces vibrations that could frighten the unsuspecting martins as they sleep. A suffocating death is now just minutes away. When the snake reaches an entrance hole to a gourd/house compartment, its head enters first followed by its body, which slides into the nest, filling the gourd/house compartment, and blocking the entrance hole. Adult and young martins alike are caught in the snake’s coils, suffocated, and devoured; small, unfeathered young may just be swallowed alive. The chances of any adult martin escaping out the hole are slim unless the snake is small and does not completely block the entrance. Also, the snake’s body is highly sensitive to the touch of potential prey and any martin that brushes against the snake is quickly snared in the snake’s coils. After the snake has consumed the martins in that nest, the snake may coil up and remain there for several days to digest its meal. Other times, the snake, if still hungry, may then continue to follow the martin scent and raid other nests in a house or gourd cluster. Some snakes, after eating their fill, leave the house/gourd cluster and climb down the pole. The landlord will have no clue that a snake has raided his/her martin colony, as the snake does not leave behind feathers, blood stains or a nest that is disarranged in any way.

Behavior Of Martins When Rat Snake Is Visible On/In House/Gourd Cluster

Purple martins will let you know when a snake is on the house or gourd cluster crossbar or if the martins see the snake inside a house compartment/gourd. The martins appear agitated and are reluctant to land on the house/gourds. They may hover around the house/gourds. Sometimes they will land on the martin house roof or gourd crossbars. If your martins are behaving in such a manner, then there may be a snake either on the outside or inside the house/gourds.

How Do Rat Snakes Climb; Understanding Snake Physiology

Rat snakes don’t need hands, claws, arms, a ladder or spiked boots. They are superbly designed to employ their unique belly scales and powerful body movements to climb a variety of surfaces. Their bellies seem to stick to rough surfaces like biological hooks, momentarily holding the snakes in place, and then allowing them to slowly climb forward without falling backwards or downwards. I have seen these snakes climb straight up cedar siding and brick walls of houses. Large diameter trees, living or dead, and utility poles are easily climbed, much in the same manner as flat, rough surfaces like wood or brick walls. I have also seen these snakes climb small diameter objects like wooden and metal poles. When climbing small diameter poles, the rat snake tends to coil around it, then slowly constricts itself upward while maintaining enough pressure on the pole to keep from sliding back down. The snake slowly meanders up the pole. The rat snake’s combination of adhesive like belly scales and powerful coiling abilities allow the snake to climb almost anything it seems.

How To Reduce The Chances Of Successful Rat Snake Predation

Grounds Keeping

There are a few grounds keeping tips that landlords can employ to at least make their sites less inviting to snakes. Snakes like cover where they can hide and look for prey. Always keep the grass around the martin pole set ups cut short and maintain an open area. Keep your houses/gourd clusters away from thickets and brush piles. Don’t plant flowerbeds at the base of the martin house poles or allow vines to climb the poles.

Rat snakes may be less inclined to crawl a long distance across an open lawn since such a move exposes them to their night enemies such as barred and great horned owls, and day enemies like red shouldered and red tailed hawks. Red shouldered hawks are a main predator of rat snakes, and I have seen many rat snakes in the beaks and talons of these hawks.

Personal Monitoring

Additionally, you may want to check the base of your martin house/gourd cluster poles during the early morning, evening, and at night to see if any rat snake is trying to climb the poles. At my previous colonies in north Florida, I have seen on a number of occasions gray and red rat snakes either at the base of my martin pole set ups or crawling toward them during the evening and night hours. On several occasions I have watched (using a flash light) rat snakes at night unsuccessfully try to climb martin housing poles that were protected with a snake guard.

Rat snake predation has been a significant problem for ALL hole nesting birds that have nested in my bird houses. Before I actively intervened and installed various pole guards, I lost numerous bluebirds, Carolina wrens, chickadees, crested flycatchers, titmice, red-bellied woodpeckers, and purple martins to both gray and red rat snakes. Also, I am amazed at the number of non-cavity nesting birds, such as cardinals, towhees, brown thrashers, mocking birds, ground doves, etc., that lost their eggs/young to rat snakes in my yard.

Possible Rat Snake Guards

So what types of guards can a landlord use to eliminate or minimize the chances of rat snake predation on his/her purple martin colony? There are a variety of systems and we martin landlords need to keep thinking of possibilities and experimenting and sharing our ideas with each other. The key is to defeat the rat snake’s ability to stick like glue to rough surfaces and/or stop the snake’s ascension up the martin house/gourd pole. Make it difficult for the rat snake. Remember: no system is totally fool proof and some huge rat snakes may defeat you no matter what you do. Here are some ideas…

Greased Pole Method (Not Recommended)

This is a very, very nasty method of deterring rat snakes and can work with metal poles if you apply GENEROUS amounts of grease to the bottom of a bird house pole and KEEP it moist. This method can defeat the rat snake’s ability to stick to a metal pole and coil around it. Many years ago I used this method. I applied enough white lithium grease to provide about 1 inch thickness around the pole and about 4 feet up the pole from the ground. I went through can after can of this nasty grease. Numerous gray rat snakes would try to climb my martin house/gourd poles that were GENEROUSLY coated, but they never got more than a foot up. I found more than one totally greased rat snake at the base of my martin house poles. Some of the snakes were so determined to reach the martins that they had taken off most of the grease at the bottom of the pole! These snakes were covered from head to tail in grease. However, I do not recommend this method for 2 major reasons: (1) it is just plain nasty and will get all over you and anything else touches it; plus it may be harmful to the rat snake or any predator that may eat the greased snake; and (2) you MUST apply LARGE amounts of grease and KEEP it greased through out the season. If you allow the grease to dry out or you do not apply enough to completely coat the metal pole, then a determined rat snake can often climb through it. I had several cases of this and I could see the horrifying corkscrew grease trail all the way up my gourd poles.

Various Pole Baffle Designs

These types of baffles offer a barrier to a rat snake and prevent the snake’s ascension up the pole. The snake either is stopped cold or crawls up into an enclosure and can go no farther. Here are some pole baffle configurations…

Inverted Bucket

The inverted bucket guards prevent the rat snake from ascending the pole when he crawls up inside the bucket and is stopped. A ten gallon inverted bucket attached to the pole about four feet from the ground provides a good rat snake barrier. Most rat snakes would crawl up into the bucket and would be stopped. However, huge rat snakes may be long enough to lift themselves up in front of the bottom of the inverted bucket and then wrap around or go over it. You must make sure there are no openings between the hole in the bucket’s bottom and the house pole that is inserted through this hole. Even a small space may allow a rat snake to squeeze through the opening and continue its journey upward.

Cone

You can build your own cone shaped baffle out of aluminum/metal sheeting that looks like a bell bottom and functions similarly to the inverted bucket. This cone could slope down 2 feet or more with a diameter of 2 or more feet. Like the inverted bucket approach, the rat snake would crawl up into the cone. A large cone barrier is a formidable obstacle to even the largest rat snakes.

Cylinders

There are several cylinder methods you can employ and they attempt to present a slick surface for the rat snake that makes it difficult for him to climb or coil around. You can slip a piece of slick plastic PVC pipe that is at least 6 inches in diameter and about 4 to 5 feet in length on the bottom portion of the martin house/gourd cluster pole. The pipe should be pushed a few inches into the ground so no rat snake could crawl under the pipe and then reach the pole. The PVC substrate is so slick that even large rat snakes may find it impossible to coil around and then constrict upwards; just make sure you keep the plastic clean of debris or mold which may provide some traction for a snake. You can also create a stovepipe out of shiny, smooth aluminum sheeting, which is similar in principle to the PVC pipe approach. This barrier prevents the rat snake from coming in contact with the martin house/gourd cluster pole.

The Purple Martin Conservation Association (PMCA) offers an excellent adjustable cylinder pole guard that combines both a slick aluminum surface and wobbly motion to thwart both rat snakes and raccoons.

But there is a potential problem with any kind of metal: weatherization. The metal surface may be come weatherized and thereby coarsened. Once this happens, then rat snakes can often climb up the surface using their belly scales and powerful body movements. You should always check the surface of any metal cylinder type guard to determine if it has coarsened. If it has, then a rat snake may be able to climb up the surface.

Rather than have this cylinder on the ground, you can attach it farther up on the pole and then cover the open top with a metal or wooden roof. The snake would crawl up into the cylinder and be barricaded from continuing on. Or the snake would try to climb or coil around the slick metal cylinder and fall back. This approach requires more planning and work to create the baffle which attaches to the pole.

If you use a cylinder approach that involves combining two halves to attach to the pole, the seam produced can provide a coarse surface for rat snakes to climb. Snakes may be able to use their belly scales to go straight up the seam.

Flat disk (With Or Without Downward Pointing Border Fence)

Rather than a cone or bucket, you may consider a flat disk (not necessarily round and could be square) approach. Such a disk would need to be around 3 feet in diameter or larger to really stop a huge rat snake, though a disk 2 feet in diameter would probably deter many small snakes. This disk could be metal or wood. You could also add a border fence around the perimeter of the disk that points downward. This downward pointing fence would add some additional protection and may keep any super long rat snake from reaching around the disk. This fence could be metal/aluminum sheeting, wood or some other material and could protrude down anywhere from 6 inches to a foot or more.

Plastic Skirt Method

I call this guard the plastic skirt. This method is rather simple and is based on giving the rat snake nothing concrete to climb or coil around. If the snake is confronted with multiple layers of loose, slick, wobbly plastic, then the snake has a difficult time employing its superb climbing skills. This method has worked for me, but is definitely not a sure thing--in fact, nothing is a sure thing when dealing with rat snakes. Louise Chambers from the PMCA has reported that a martin landlord used this approach and rat snakes still managed to climb the pole.

I used relatively thick black agricultural plastic sheeting that can be purchased at any home improvement store. You'll also need a pair of scissors, some wire, a yard stick, and if you want to attach the plastic to wooden poles with nails, nails and a hammer. Cut a piece of plastic sheeting about 5 feet by 5 feet square; this can be larger if so desired. At about 5 feet from the ground, began wrapping about 6 inches to a foot of the plastic top tightly around the pole, leaving the remaining 4 feet or so of plastic loose. The bottom of the plastic should be about 6 inches from the ground. Take some the wire and wrap it tightly around the top of the plastic sheeting to hold the plastic firmly to the pole. At this point the plastic guard should somewhat resemble a skirt or bell bottom. The plastic guard is narrow toward the top and gradually flares out toward the bottom. Make sure the bottom portion is loose and flares out.

The plastic guard works in many cases because the rat snake has a difficult time climbing or coiling around a slick, loose, wobbly plastic skirt--there is nothing solid for the snake to cling to. Also, the rat snake will often try to ascend the pole that is protected by wrapped plastic. The snake will be squeezed tighter and tighter while trying to climb the pole inside the plastic skirt and being compressed against the pole by the multiple layers of gradually tightening plastic.

I have observed several rat snakes try to climb my martin gourd poles that were protected with plastic skirt guards. In each case, the snake was unable to navigate around the plastic or the snake climbed up the pole inside the plastic skirt and then was forced down due to the gradual compression of the plastic against the snake’s body. One year I watched a 3-foot long corn snake try and try to climb around and through a plastic skirt guard. The snake was unable to accomplish this maneuver.

However, plastic sheeting often deteriorates after prolonged exposure to the sun and the elements. This weathering may reduce the plastic’s slickness and flexibility, thereby giving a rat snake a chance to climb on or around the plastic. I began to notice this problem on some of my plastic skirt guards and worried about rat snakes overcoming the baffles. Because of this potential problem with deteriorating plastic, I quit using the plastic skirt method beginning in 2003.

The Net Trap

No snake barrier is totally fool proof and some really big and determined rat snakes may defeat all the guards previously discussed. I have never underestimated these snakes in their quest for warm blooded prey, particularly a birdhouse or gourd cluster full of purple martins.

However, there is a barrier that may work when all others fail. It is called the net trap, a device that just doesn’t stop a rat snake but catches the snake. If you go to a garden center, home improvement store or even Walmart, you should be able to find something called bird netting. This is the plastic netting that you use to protect your fruit trees and plants from hungry birds. It is made of thin material and comes in various mesh sizes. If you can’t find the bird netting locally, you can search the Internet and find a number of companies that sell this product.

Okay, what is a snake net trap and how do you build and install it? And of course you want to know how this thing works, but more on that later. Snake net traps come in different configurations and are usually bunched up wads of bird netting that circle like a wreath the pole of a martin house or gourd rack or even hang down like a messy skirt. These traps can be attached above a standard snake guard to serve as a final barrier or these traps can be used alone. But if you use it alone, then there may still be a risk of raccoon predation. You can even place these traps at the base of the poles or stuff the netting inside various other snake guards. Since these traps actually catch snakes, think of the snake net trap as your insurance policy in case your regular guard should fail.

There are a number of very simple ways to construct a net trap from bird netting and attach it to martin housing poles. You need the bird netting, a pair of scissors, a measuring device, some pliable wire and a wire cutter. Since there are both thick and thin rat snakes, depending on age, it is best if possible to use a combination of mesh sizes in your net trap. Mesh squares of ½ and ¾ inch would give a good range of coverage. So if you were going to use a combination of mesh sizes, then you would have at least two packages of bird netting to work with.

Here is one way how I construct my net traps and I only use bunched up wads of netting that completely circle the martin housing pole like a fluffy wreath. First, I create a simple support wire base for the pole where the netting will be wrapped and attached to form the trap. Cut two pieces of pliable wire (I use No. 10 or 12 plastic coated copper wire.) about two and half feet long. Wrap one around the pole at about three or four feet above the ground or just above your standard snake guard baffle. Then twist it tightly against the pole so that two pieces of wire protrude out about six or more inches in a V shape. Do the same with the other wire on the opposite side on the pole. Bend each end upward so that about two and half or more inches are parallel with the pole. So you have four wire prongs protruding out in different directions with the ends curved upward. To help hold the wire to the metal, you can first wrap some duct tape around the pole. The tape provides a “stable adhesive surface” for the metal wire and may help keep it from slipping downward.

Now cut out a piece of netting about two feet wide and around six feet in length. This sheet can be longer if you choose. If using a mesh combination, then you would have two pieces. I still use two pieces of netting if only using one mesh size to create a thicker net trap wad. In fact, I often have two complete systems on my poles to create a large bunched up wad of netting. Then fold the netting like you would a sheet to create about a one foot wide piece to make it easier to wrap. Start wrapping the netting around the wire support base while inserting the mesh from time to time into the upright wire prongs. Do this over and over again until you have completely encircled the pole and created the net trap. Keep the netting fluffed out as much as possible. Then bend over the ends of the wire prongs to help hold the netting in place. Fluff up the netting and reinsert it into the prongs as necessary. Make sure no gaps exist in the netting that could allow a snake to slide under and bypass the mesh. Think of this as a bunched up fluff of netting that sticks out to the side, up and down all around the pole.

I'm sure you can use other ways to attach the netting to the martin house or gourd rack pole. It is a simple system. You could wrap the netting around the pole first and then use thin pliable wire to twist tie the trap securely or even tape it. Or you could bunch up of your sheet of netting first, insert the wire through it and then twist tie the trap to the pole. The main objective is to create a wall of netting that completely encircles the pole like a wreath or hangs down like a messy skirt.

Now, how in the world does this thing work? How does such a trap ensnare a snake? Snakes crawl and weave themselves through vegetation. Snakes also can deflate their bodies to squeeze through smaller areas. Then their bodies inflate again back to their normal size. And snakes have scales, somewhat like a fish.

When any snake is confronted with the bunched up netting on a martin housing pole, he starts to weave himself through it just like he would do if slithering through grass, vines or other vegetation. As he weaves through the mesh, his body responds to the netting by deflating and inflating. In short order, he gets hopelessly entangled in the mesh as his scales are caught in the net. This is similar to gill nets that are used to catch fish. And then you have him. Small snakes may be caught in their middle area while larger snakes may only get a short distance and be ensnared just a few inches below their heads. There is no escape, as the snake can’t back out of the netting with his scales trapped in the fine mesh. It is almost a perfect snake catching system and the vast majority of snakes will be caught.

But even the best things in life have a price. Now comes the hard part and if you are not willing to do this, then you should not use the net trap. You have to remove the living, squirming and sometimes angry rat snake from the net! However, not all rat snakes are that aggressive, particularly ones that have been caught in the netting for a good while and these snakes may be rather passive. But, big rat snakes can bite and bite hard. They have drawn blood from my hands and arms. So you must not have a snake phobia and be willing to take them out of the netting UNHARMED. You can’t just pull him out as his scales are firmly ensnared. You have to cut him out gently. I grab the snake by the back of his head and then use a pair of scissors to cut the netting from his body. This action may destroy part of the net trap, but they are so easy to build and cheap that you can replace them quickly.

The net trap can be used as the LAST hurdle for any rat snake that manages to defeat your normal guard. And you MUST monitor such a trap daily. Most rat snakes hunt during the night or late evening or early morning. You should check any martin housing poles frequently to see if any snakes have been caught. Do NOT let snakes remain in these traps and be exposed to the hot sun for long, as the snakes will die. The purpose of the trap is NOT to kill the snake, but to ensnare him temporarily and prevent predation on your martins.

For Maximum Protection, Use A Combination Of Guards

If one system fails, then it makes sense to have a back up. An inverted bucket, PMCA guard or PVC cylinder baffle with a net trap above it would be a formidable barrier to any rat snake. First, the snake would have to defeat the first guard. If the snake succeeded, then it would crawl into the wad of ½ and ¾ inch square mesh netting and be most surely entangled. Such multiple barriers may be the best approach in defeating determined rat snakes.

Don’t Let Your Martins Become Victims Of Rat Snakes

No responsible purple martin landlord should erect a martin house/gourd cluster without attaching a pole guard to eliminate or minimize rat snake predation. Remember: these snakes are everywhere and very common in the Deep South. They CAN easily climb both wooden and metal poles. They don’t need sight or sound to find your martin colony. All they need is the martin’s scent and their superb biological sensors will guide them right to your martin colony. If you did not have a snake guard on your house/gourd cluster pole this year, be sure to start planning to add one for the next martin season. It will only be a matter of time before a belly crawler finds your colony…think about that. Think about that rat snake entering a martin nest during the dead of night and what happens to the martins. Protect your colony.

Steve Kroenke

[Guest]

I didn't see anything in your post about snake repellant pellets. At my local lawn and garden store I saw a product for sale that was supposed to repel snakes from the area. Do you have any experience with this?

[Steve Kroenke]

Hey,

I have never used any kind of snake repellant pellets. I am curious about how these would work. Perhaps they interfere with the snake's sensitive Jacobsen's organ? Also, seems that the pellets would eventually decompose due to rain and the elements? A friend told me once that you can sprinkle boric acid around an area and this will keep snakes away. But that may keep everything away! I don't know. I will try to research this concept of a chemical deterrent for rat snakes and see if there is any validity to it. I do know that coating large amounts of white lithium grease on a pole will not stop a rat snake from trying to climb it. So the "odor" from the grease apparently does not deter the snake. Thanks for sharing your comments.

Steve

[Steve Kroenke]

I did a Google search on, ?snake repellents do they work?. Websites from universities or independent scientific organizations indicated that snake repellents do not work for the most part or they questioned the effectiveness. Snakes just crawled over the chemical barrier. Of course, businesses which promote the snake repellents provided their own studies to prove that snakes are deterred by their products. One of the businesses listed the species of snakes deterred and the efficiency rate. A key martin predator is the corn snake (red rat snake) and the product only worked 17% of the time in keeping this species from crossing the chemical barrier according to the business? study. Also, there could be methodology problems with these business studies relative to sample size (number of snakes tested) and scientific controls.

One big problem with chemical repellents for snakes around martin colonies is the open environment. The repellent is not confined to a building or some other enclosure where a concentration of the repellent?s odor could build up, but is out in the open. You would be placing some pellets around a martin house pole and these pellets would be exposed to heavy rainfall, sun, wind, and other environmental elements. Could you get a sufficient concentration of the chemical repellent that would interfere with a rat snake?s Jacobsen?s organ during the rain and windy weather? I doubt you could. The repellent?s ?scent? would be diffused over a wide area and be reduced in concentration. Plus heavy rainfall may completely wash away the pellets or dissolve them into the soil. This may present an environmental hazard for subterranean invertebrates and other creatures.

The concept of chemical repellents that may interfere with a snake?s Jacobsen?s organ and sensory system and shut it down around a martin colony is interesting. But I question if there is repellent available at this time that will do that effectively and safely. Perhaps some day a chemical will be created that can be safely applied to the bottom of martin house poles that will do just that and not harm any snake or other creatures.

So for now, I would strongly recommend a snake guard/net trap combination for rat snake deterrence and not rely on snake repellents.

Steve

[geezer]

Hey Steve, We appreciate you. Your posts are great.

I lost 1 complete nest to snakes in 2004, and 3 nests in 2005. Everything, including adults, hatchlings, and eggs were gone without a trace. Something had to be done. The snakes do serve a very good purpose in my area, but the PM's must be protected.

After some research in this group, I got some bird netting and black plastic and attached it to the bottom of my two poles. It worked very well. I caught 9 snakes in about 4 weeks. Unfortunately for the snakes, the bird netting is a death sentence. They get all entangled, and it is very difficult to extract them.

The netting does work very well, but next year, I may try the plastic skirting without the netting.

[Steve Kroenke]

Hey,

I am glad you like my posts. Hope they have been helpful.

If you can get to the snake quickly, then you can save him. Last year, I caugt a huge 5 foot long gray rat snake that cirumvented my stovepipe guard and then became entangled in my net trap. The snake was apparently caught sometime in the morning while I was at work, but survived until I got home around 5:00 pm. The day was overcast and that may have kept the snake alive. I was able to remove him unhurt and released him about a mile away. I caught a number of snakes during the night and they were still alive in the mornings when I removed them.

However, some rat snakes do succumb when caught in the netting, particularly if left entangled during the daytime. The sun will kill them quickly.

I agree that purple martins must be protected from rat snakes. The net trap has been a lifesaver for martins and other cavity nesting birds in my yard. I will never erect martin housing without a net trap attach to the pole.

Good luck.

Steve

[Guest]

Steve, Thanks for the article. In your opinion , are Rat snakes the most likely predator of Martens that most Landlords will incounter? Where would Owl's fit into the percentage?

[Steve Kroenke]

Hey Blake,

Rat snakes are significant predators of martins primarily in the South though the black rat snake does live farther north. Barred and great horned owls probably live in nearly every location where martins nest including the upper mid west, northeast and Canada. So from a geographical distribution perspective, owls are more widespread and probably are a potential predator of martins in more locations. However, rat snakes are more plentiful and you may many individuals living near your martin colony. Owls are territorial so you may only have one pair in your area.

Another MAJOR predator of martins is the Accipiter hawk which is both a migrant and permanent resident in many locations where martins nest. The two hawks are the Cooper?s and sharp-shinned and they raid many martin colonies from the South all the way into Canada. The Cooper?s is more widespread and nests in nearly every location where martins breed.

It is difficult to say which of these predators would most likely be encountered by martin landlords because so many factors influence the chances of predation. These include location and size of the martin colony, surrounding terrain, climate, local predator population densities, etc. Generally speaking, since rat snakes are so plentiful, I would probably say these predators would be most likely encountered first followed by Accipiter hawks or owls in the South. As you go farther north into the plains states, mid-west, northeast and Canada, rat snake encounters tend to diminish because of lower population numbers while Accipiter hawks and owls become more of a threat. A landlord in Michigan, for example, would probably have a very low encounter rating for a rat snake and a much greater one for an Accipiter hawk or owl.

I hope this information has been helpful. Good luck with your martin colony.

Steve

[Guest]

STEVE,
I'VE HAD NO TROUBLE YET WITH SNAKE RAIDS BUT I HAVE SEEN 3
RAT SNAKES THAT PEOPLE HAVE KILLED IN MY AREA. ALL 3 WERE OVER
6 FT. LONG.
LUCKY IN ARKANSAS,
MARK HARPER

[rickluc]

I bought my property in 1999 and put in a foundation for my house. During all the digging I came up with a lot of rocks about the size of a 5 and 10 pound bag of sugar. I built a lose rock fence about 3 feet high, approx. 3 feet wide, and it was about 30 feet long leading down to the water front. In the early summer of 2000 I kept seeing a few snakes sun bathing on top of the rock fence. I went to my local garden store and bought some snake repellent pellets. I sprinkled two jugs of this on top of the rock fence. To this day I haven't seen anymore snakes sun bathing on the rocks. I find it hard to believe that this product has lasted this long. But then again this is a perfect place for snakes, and I haven't seen any.

[Steve Kroenke]

With the purple martin season rapidly approaching, rat snakes will soon be emerging from hibernation and looking for prey. That prey could be your martin colony. I am re-activating this older posting of mine that deals with rat snake predation. Folks should consider installing predator guards on their martin housing poles to deter rat snakes, particularly in the Deep South.

Steve

[Emil Pampell-Tx]

Steve, have you ever tried trapping them. I am thinking that a wooden trap that is real dark may work if you bait it was a dead sparrow, but I don't know anything about the traps..They apparently do work, I saw them take snakes out of traps on TV, but didn't get any details on the traps. Maybe a person could haul them away a couple miles

[Steve Kroenke]

Hey Emil,

I have never tried any kind of snake trap other than the netting. I believe they have such devices and you can do a Google search on the Internet to find such traps. You would probably have to use a live sparrow or rat as rat snakes eat live prey. I believe it would work at the base of your martin housing or probably anywhere in your yard. The snake would first be attracted to the sparrow or rat inside the trap and go there, only to be trapped inside. It might be a promising way to safely capture rat snakes and then release them away from your martin colony. It would be much better than trying to remove snakes from the netting.

Steve

[marshainpuntagorda]

Thanks again Steve, for your information...I have posted several pictures on the forum showing our snake encounter. A BIG rat snake and there was another after that one! We caught it in the bird webbing you describe..the way we found out about the webbing was either in the PM magazine or one of our fellow PM Landlords drew a picture that we followed to make our last/first resource to capture those critters who like our warm babies...We almost lost our colony! Ours should be here by the first week in Feburary. Wishing all a great season and please read the article about bird flu and landlords!

Thanks, Marsha

[Steve Kroenke]

Hey Marsha,

Thank you for adding your photo of the rat snake caught in netting. At my previous colony in Tallahassee, Florida, I caught many gray rat snakes in the net traps, including a huge nearly 5 footer. I have a posting on the Forum showing this rat snake caught in a net trap. Rat snakes are plentiful in the Deep South and many folks lose martins to these predators each year. The net trap has been a life savior for the martins in my colony. At my new site in northwest Louisiana, I didn't have any rat snakes in my traps in 2005. But that can change in 2006.

Good luck in 2006.

Steve

[Steve Kroenke]

Soon the rat snakes will be emerging from hibernation and they will be HUNGRY! I am re-activating my post on rat snake predation and encourage everyone to ensure their martin housing poles are protected. I have installed net traps on all my martin housing and these traps are very efficient in thwarting rat snakes. Rat snakes are particularly numerous in the Deep South. These snakes are already "on the move" in my former home state of Florida. So be prepared for them.

Steve

[zoefluf]

Can someone post a picture of the netting trap? Also how do you make a trap and where can I get the materials? We have a lot of snakes where I live in southeast Louisiana! And they soon will be coming out of hibernation.

[Steve Kroenke]

The net traps are described in detail in my article on rat snake predation. Let me know if you still have questions about them. Also, you can buy the bird netting at most garden centers or home improvement stores like Lowes or Home Depot.

Here are some photos of two of my net traps that have worked well in capturing rat snakes of various sizes. The first photo shows a double layered net trap made from bird netting and contains both ? and ? inch mesh squares. The second is a single layered trap. I first wrap some electrical or duct tape around the square poles to create a foundation for the wire support base. Then I twist some No. 10 or 12 plastic coated copper wire or just plain clothesline wire around the tape and create a pronged support base. The netting is wrapped around the wire prongs and fluffed out to create a circular wreath. I try to create a thick wad of netting in my traps so that the snake has hundreds of mesh squares to face. You don?t want the mesh to become too compressed and matted. Also make sure there are no gaps between the mesh and the pole so that a snake could slip under the netting. He will start weaving through the mesh and nearly always becomes hopelessly entangled. The ? and ? inch combination is designed to capture small and large diameter rat snakes.

Steve

[Steve Kroenke]

I am re-activating my article on rat snake predation and encouraging everyone, particularly folks down south to place some kind of snake guards on your martin housing poles. Yesterday, I found a huge rat snake crushed on our road, so the serpents are now stirring with the arrival of warm weather. They will be HUNGRY! I have included two photos of my net traps including a single layer and double layer variety in the previous reply of mine. You can also place a wad of bird netting at the bottom of your martin housing poles and this will catch the snakes before they can start their ascent up the poles. I have caught a number of big gray rat snakes that way. I also included a photo of a large gray rat snake caught in one of my net traps.

Steve

[loco for purple]

Steve,

I want to thank you for the idea about the netting at the bottom of the pole.I just caught one a couple of days ago at the bottom of the pole.This year I started using 6inch pvc pipe in four ft lengths. Last year even with all my netting I lost two martins to a very small snake.I never posted it ,I was pretty upset by it. The snake was so small it couldn't eat the martins, they were to big.It just killed them. And yes Steve, I had both sizes of netting.That is why I have the pvc pipe this year another line of defence.But your information has helped me save many of my martins a gruesome death thanks again...