SREH ADVISORY

SREH's May Be Damaging PM Feathers or More

Published in The Scout Report Vol 9 (1), p.4.
By Rick Cruz

Fellow martin bander, Keith Kimmerle of Columbus, MS, recently asked me if I had noticed excessive wear and tear on the backs of Purple Martins using crescent shaped starling-resistant entrances (SREHs). Since he knew I had the use of a spotting scope he suggested I look for curled, ragged edges of feathers around the regions of the nape, upper back, breast and rumps of martins. These specialized holes are not commonly used in my particular area with the exception of maybe three people including myself.

Each year I read as many bands as possible so it would be easy to get a close look at the birds that are using these holes. I hate to admit it about the SREHs but he was right. I have spotted several martins with these worn areas on their necks and backs. I was very specific about the birds I chose. I would wait and watch to see what martins were actively feeding young in crescent-shaped holes. I would then focus all my attention on that particular bird. I even saw a few of these that are using the new Excluders. Not all the martins using these showed signs of wear but most did. My study colony did not, since my entire crescent and Excluder holes are adjustable and are made out of wood or 1/8-thick Teflon(r).

I visited four other colonies with SREHs. One colony had all homemade, fixed Teflon(r) crescent holes. Three birds out of six pairs showed signs of feather wear and tear. My study colony has 43 pairs with a combination of adjustable crescents, and Excluders. These feathers showed no wear and tear. This could be due to the fact that I keep the holes at 1-1/4" instead of 1-13/16" until the eggs hatch. Then, I make each hole larger as the young get more demanding. Another colony had a combination of factory crescents on a Lone Star house and fixed homemade wood ones on a Trio Grandpa. I saw no feather wear and tear on any birds out of six pairs. I suspect this may be due to the wood. Charles Mc-Ewen, the original crescent designer, intended for his crescents to be made from wood and not from metal so martins could use their claws as leverage to propel themselves through the crescent, half moon entrances. In addition, the fact that the Lone Star house features crescents flush with the floor of the porch may account for the fact that there is less resistance for the martins entering, therefore less wear and tear on their feathers as they walk right into their compartments.

The last colony that I observed is using all factory-made Excluders. Several birds showed feather wear but not to the extent of the one colony with crescents with the exception of one ASY-male that really struggled with his Excluder door each time.

Earlier this spring PMS/NA member Dave Pankow, Willow Springs, IL, informed the Society and me of an ASY-male that brutally died in an Excluder hole. He assured me that it had died trying to get out. He witnessed the bird struggling to get in but never witnessed its exit. A few hours later he noticed this same bird immovable, halfway out of the entrance. I saw the bird shortly after its death. Its eyes still clear and fresh. Its back was ripped to shreds. All the feathers from the back of the neck to just past the shoulders were scraped off. The hot picked skin looked like fresh ground beef. Dave Pankow was livid. In his thinking, here was a bird that survived a 4000-mile trip only to die a few days after its return to a place it considered home. Though his other martins were using Excluders, he immediately replaced these compartments with round holes not wanting to repeat this tragedy again. In this situation, it is possible that this martin was slightly heavier than average martin in weight. It could also be that this bird just panicked, not having learned how to use the hole correctly, or it could have been a combination of both.

The crescent SREH seems to have its own perennial problems as well. Each year there are reports of martins getting their wings stuck at some odd angle. Most cases have not resulted in death or injury due to the swift response of the observing landlords. But crescents have caused some martin deaths. It should be noted that this does occasionally happen with a round hole but not frequently.

These SREHs obviously have some problems. Landlords need to be aware of them. They are not the perfect solution for everyone. My observations are not the result of careful scientific study but examinations made over hours at each colony. At the moment I can only speculate. Crescent holes were originally intended to be made of wood. The metal edges of the holes made to fit Trio houses are going to be more abrasive. The 1/2" lip in these doors does not help. The martins have to lift themselves up and press against the top edge driving it deeper into their backs. If this lip was not there the birds just push themselves closer to the porch floor flattening and limiting the amount of pressure on their backs. The Excluders are a bit different. A martin needs to open its wings slightly before it can tilt itself into the hole. By doing this, it limits the contact it has with its back neck and shoulders.

The best solution for this particular problem is to make an adjustable smooth plastic plate for the crescent hole coupled with 1/2" wooden plate in front and in back of the hole making it a flush floor entrance. This does not work for the Excluder. The small prongs on this hole need to be up off the porch floor. It teaches the birds to lift their shoulders for entry. Starlings will always be a threat. A 6" x 6" compartment may not be used as a nest by these birds but that will not stop them from going in and wiping out its contents. A round hole is probably best no matter what size compartment is used. The reality of it is that few of us can guard a martin house all day. Modifying these doors to be adjustable takes a little time but seems to be the best alternative for the time being.

At the time of the crescent debut, PMS/NA member, Ed Donath, mentioned that this was going to happen. Like anything else there needed to be more landlords using these holes before anything could truly be seen. There have been problems and they will continue unless all are made aware. Remember! All martins you see actually vary in size. These holes are going to favor the smaller birds. The biggest ones are going to have problems. Some way we are going to have to accommodate all of them as safely as possible.

Keep you eyes and ears open when using these starling resistant entrance hole!