SREH: is there a best type

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John Miller
Posts: 4779
Joined: Mon Mar 22, 2004 9:11 pm
Location: St. Louis, MO

Hi Folks

I've been reading everything I can now for two years here, and been amazed at how much has been learned in the last decade or so about managing purple martins.

One topic that has concerned me is the use of SREH .
One experienced landlord said that there are drawbacks, but that there's really not a choice. That's true. What'd I'd like to know, is there a consensus now on which type of SREH is easiest on martins while being reasonably effective against starlings?

As a new landlord, I've used aluminum crescents with success. But I've long been disturbed over reports of martins getting stuck -- straight on when they forget to shimmy, or from wing entrapment. If this happened to humans and aluminum crescents were a drug, it would be pulled off the market pretty quickly. (not to say I may or may not have a little Viox hoarded away)

It seems to me that folks are finding the WDW or "modified" excluder in a PVC plate to be best in posing less risk to martins while keeping starlings out. Are these holes easier for martins to learn?

What do others think now that all these types have been in use for a few or more years?

John Miller,
St. Louis, Mo
Matt F.
Posts: 3923
Joined: Mon Feb 28, 2005 9:48 am
Location: Houston, TX

John,

I too am considering converting over to modified excluders, from SREHs.
Here's a thread from earlier this summer, asking a similar question.

http://www.purplemartin.org/forum/viewtopic.php?t=448
Laverne
Posts: 2216
Joined: Thu Jan 08, 2004 1:58 pm
Location: TX/Alvin
Martin Colony History: Erected 1st house in 1997. Birds were checking it out before Mike got down from the ladder. Six cavities had a little colony 1st year. Grown to 88 cavities all gourds with near 100% occupancy. Most important factor for success is rain = bugs.

John Miller wrote:is there a consensus now on which type of SREH is easiest on martins while being reasonably effective against starlings?

As a new landlord, I've used aluminum crescents with success. But I've long been disturbed over reports of martins getting stuck -- straight on when they forget to shimmy, or from wing entrapment.
Hi John and Matt.

I have to say something in defense of the crescent SREH (aluminum or plastic). Purple Martins fight viciously. I believe most hangups in entrances and porch rails occur during the squabbles over cavities. They hold on to each other by the tail, by the foot, by the wing. I think the escaping bird in its flapping and flailing about is the one who gets stuck. Fights will also occur when a Starling or Sparrow tries to take over the cavity a PM wants. And, one time I found two females dead inside a gourd. I'm still not sure what happened to them. They either killed each other - there may have been a third PM - or the third bird could have been a Starling or Sparrow. I'm inclined to believe there was a third bird.

My point is: I believe some kind of frantic unnatural behavior causes these birds to become stuck. Normally, they are fine.

There is not a SREH made that guarantees PMs won't get stuck. We are narrowing the opening to prevent the entry of a bird just a little bit bigger than a martin. The tolerances are tiny. The fit is tight. When you add fighting and escaping to the mix, somebody somewhere someday is gonna get stuck.

I recommend closely monitoring your housing (especially during the early part of the season when they are selecting and fighting over cavities) and use a SREH'd entrance. They all work well. Remember to keep those porches close - between 1/4" and flush.
Sincerely,
Laverne
John Miller
Posts: 4779
Joined: Mon Mar 22, 2004 9:11 pm
Location: St. Louis, MO

Laverne

I disagree that we may assume all SREH work equally well in terms of equal risk to martins. I don't think we really know that, but it's what I'm trying to find out.

John Miller,
St. Louis, Mo
Robert McCallum
Posts: 215
Joined: Thu Mar 18, 2004 8:34 pm
Location: Oklahoma/Tulsa

John,
Reports exist of sticking in crescents. If there are no reports of sticking or other problems in WDC openings, then we must presume that the WDC have a small edge. Are there reports of sticking or acceptance with the WDC?

bob mc
Steve Kroenke
Posts: 4342
Joined: Fri Nov 28, 2003 6:49 pm
Location: Louisiana/Logansport

Hey John,

Srehs are unnatural entrances for purple martins so martins may assume unnatural physical contortions to enter and exit. Martins did not evolve in such narrow entrances; they evolved in round holes. A purple martin may be thicker than the 1 and 3/16 inch height of a crescent hole, which is even smaller in height as it tapers to the ends. So the martin must flatten its profile, position its wings appropriately, and then wiggle/shimmy in. When martins execute this maneuver, they subject their back, neck and breast feathers to a tight, restrictive fit. Think about this: what if you had to squeeze everyday to enter the front door of your house and feel the doorframe scraping against your skin! And when martins do this literally hundreds, maybe thousands of times each season, then a significant amount of friction is placed against their feathers. Some materials like thin aluminum may damage the feathers.

More significantly, these tight entrances can definitely result in martins becoming lodged after they have lost a battle with another martin and are struggling to exit. This year we found four dead martins lodged in standard crescent holes in aluminum houses. The martins were trapped in various ways, including one martin that had some of his body out and his head turned inside the entrance. This male martin had lost a fight with another male and all the feathers had been pecked off his head. If we had not discovered this dead martin, then both a male (victor) and a female martin, which were inside the compartment, would have starved to death. Other martins had part of their bodies and one wing out.

Also, martins are sometimes injured after struggling for a long period of time to exit a crescent. I have found blood smeared all around crescent holes of both aluminum and plastic housing after a martin was temporarily lodged and finally broke free.

Crescents may encourage longer intra-specific battles between martins because of the difficulty of the loser in exiting. I have watched martins struggle and struggle to exist crescent holes on both super gourds and Trio aluminum house compartments. These battles tend to be of longer duration than in housing with round holes. When longer battles occur, this increases the chances of martins being injured or killed.

Since martins may be thicker than the 1 and 3/16 inch height of crescents and martins do vary some in size/weight, most crescents can probably trap martins under stressful conditions. Any time you create an entrance hole that is smaller in height than the girth of a martin and forces a martin to wiggle, squeeze or shimmy to get inside, there will be a chance that martins can become stuck or can injure themselves.

Is there a ?best? sreh? I don?t know. I have not had any experiences with the WDCs and these may prove to be more ?friendly? to martin feathers, back/breast bones, and internal organs than crescents or excluders. And most importantly, these entrances may not trap martins after a violent fight. I have observed many martins using crescent and excluder type srehs and martins can be injured and trapped when martins are fighting and the losers are trying to exit. These srehs also can delay the entering/exiting of stressed martins that are under attack by Accipiter hawks and owls.



Steve
Matt F.
Posts: 3923
Joined: Mon Feb 28, 2005 9:48 am
Location: Houston, TX

Man do I miss the good old, carefree, round hole days!
John Miller
Posts: 4779
Joined: Mon Mar 22, 2004 9:11 pm
Location: St. Louis, MO

I do hope the WDC entrances are easier on martins. I'll be trying some in gourd tunnels next season.

Just looking at WDCs, martins would appear to have more maneuver room laterally should one get a wing out, and should a martin just get stuck rushing out, I'd think they could hold their wings out more to wiggle out better.

I did not have any stuck martins this year in my house aluminum crescents in a whopping seven pairs, but because of my concern, I had opened all these slightly at the bottom -- between 1/32 and 1/16 of an inch -- by carefully bending a tab inward. I had no starlings enter in a heavy starling area, but that's not to say I didn't increase starling risk. We know that distance to the floor is important in keeping starlings out as well -- mine is 1/14 inch.

It's not my intent to discourage use of crescent SREH, but to express caution based on what I've read here -- and to continue learning.

John Miller
Thurman Seber~TN
Posts: 416
Joined: Tue Nov 11, 2003 2:02 pm
Location: Alexandria , Tennessee

I have a pretty fair size colony and did not witness a single martin hanging in an sreh. Not this year, last year, nor any other year. This is not to say that others have not seen it, but I can't help believing, if it was a common occurence, I would have seen it at least one time.
My crescents are rounded in the corner, which may go a long way in preventing this problem.
I use crescents, excluders, and WDC with about equal results. :shock: Many times I have seen what, at first glance, seemed to be a stuck martin. In every case, it proved to be another martin inside the compartment, holding on to one trying to get out and escape the fight.
By the way, I use to see that sometimes in the good old days when I had round holes. Do any of you remember how the martins use to build mud dams in the mouth of the round holes? It almost looked like they were trying to make them crescent shape, didn't it
:?:
Thurman Seber, Alexandria, Tennessee
Steve Kroenke
Posts: 4342
Joined: Fri Nov 28, 2003 6:49 pm
Location: Louisiana/Logansport

Hey Thurman,

I use all round holes and none of my martins (81 pairs) this year built mud dams even in the vertically shallow Lone Star houses with entrances only one inch above the floor. Not a single mud dam was built in my vertically deep natural gourds. I do provide well constructed pre-built nests and this may minimize mud dam construction behavior.

My neighbor uses crescent holes and many of his martins used mud dams in the T-14 houses which have vertically shallow but horizontally long compartments with the entrances flush with porches. Some had very elaborate mud dams! Even some of the gourds with crescent holes had large mud dams. Some of these mud dams looked almost like barn swallow nests!

Mud dams tend to be commonly used in shallow compartments where the holes are close to the floors. I often had them in the past in my Trio houses and some gourds with vertically shallow hole placement. I believe many martins use the mud dams to block off visibility into vertically shallow entrance holes which are close to the nest bottoms. Martins used to nest in vertically deep woodpecker cavities and there was no need to obscure the entrance hole with a mud dam. The nest contents were well protected deep inside the cavity. Humans changed all that by providing nest cavities that are vertically shallow and more visible from the outside.

Steve
starling shooter
Posts: 452
Joined: Wed Nov 19, 2003 7:43 pm
Location: Central MO

I had great luck this year with Sandy's cresents with rounded ends and with the WDC. I feel the WDC are basically starling proof. I have had no starlings enter in either but I did some testing on live volunteer starlings (they volunteered by going voluntarily into my nestbox traps). They could squeeze out of the cresents fairly quickly but they really had to struggle to get out of the WDC. A couple couldn't get out, even if their life depended on it (which it did).

I had SREH anxienty also and left a few round holed gourds. After having to police the rack (see my handle) and finally witnessing how quickly and easily they could enter SREH, I will offer nothing bout SREH in the future.

If anyone asks me, I'll tell them SREH is the only way to go since most areas have an abundance of starlings.
Bob Buskas
Posts: 600
Joined: Sat Nov 15, 2003 8:08 pm
Location: Wetaskiwin Alberta, Canada

I agree with Thurmans post 100%. I too have used nothing but SREH of all styles and have never ever had a Martin get stuck. I also can say that I have never lost a Martin to a Starling since using SREH. I am 100% SREH at my colony sites and will never go back to round entrances, I love my Martins too much!
Bob Buskas, Alberta, Canada (The Northern Sky's Colony) Supplimental feeding is the key during bad weather, but you must train them to feed ahead of time.
Guest

John Miller, I think a lot of people have asked this question. I know that I used to. It appears that all you get is everyone's opinion, which is exactly what a reply is. I think a lot of people have valid points.

You have to respect Steve Kroenke's response because he has a mega colony and obviously did not get to that level without being knowledgable. However, you have to respect the other landlords as well because they are only stating their personal hands on experiences.

I personally use the crescent entrances because of screech owls. I have had starlings and house sparrows here, but I have never had them actually nest in a compartment. A screech owl will fly through a round hole faster than boiled okra through a hound dog. However, I have been told they will fit through a crescent entrance as well. I know the crescent entrace will at least make it more difficult for a screech owl.

I look at it like this. Just do what works for you. I can tell by your inquiry that you obviously would not be satisfied with round holes. If you have already decided to go with some WDCs next year, then go with that. This is just my opinion and honestly, I have not made up my mind either.

I tend to want to go with all round holes because it does seem easier for the birds to enter, however, it also opens the housing up to unwanted guest and predators.

One thing I would like to add, and I probably will be beaten with a wet garden hose for saying it. Remember, there are always going to be people out there trying to sell you something. So no matter what you have, someone has something better, which of course is going to cost you.
Guest

I lost a bird in an excluder entrance this year (it trapped a pair in the compartment but I found him in time to release them) .

I also have a t14 with crescents and have just finished making a jig for making WDC entrances. There can be no doubt that the WDC design will prove to be the least 'stressful' on martins. The prongs are lower than on excluders and like John mentioned provide much more room for lateral movement.


All the houses I built from now on will have WDC entrances and hope to convert my existing houses also.


I will still use crescents where adjustable sreh entrances are required - and convert to WDC once they have done their job. This is quickly achieved when using entrance plates with the same bottom dimension.
Thurman Seber~TN
Posts: 416
Joined: Tue Nov 11, 2003 2:02 pm
Location: Alexandria , Tennessee

As has been often stated, a martin colony can be successfully managed with sreh or round holes. I do not try to pressure people in either direction. In years gone by, I provided round holes. For the past few years, I have provided nothing but sreh. I will never provide another round hole for martins, unless starlings become extinct.
I did have 162 nesting pairs this past year. I had no martins stuck in an entrance. I did not witness a starling enter a compartment, in fact I think they have pretty well given up and quit trying.
I will keep on saying that sreh will work, and work well, for those who choose to use them. Crescents will work. Excluders will work, although I like them less and use fewer of them. The WDC entrances work well, and I am going to them more and more. Round holes will work if the landlord will deal with starlings (I did when I had round holes as best I could).
So, being a person who believes in everyone doing things to suit themselves, I say, do it however it suits you. I do.
Thurman Seber, Alexandria, Tennessee
John Miller
Posts: 4779
Joined: Mon Mar 22, 2004 9:11 pm
Location: St. Louis, MO

Some good insight here to what I wanted to know -- just what is the risk in an aluminum crescent of a martin getting stuck, and second, is there an alternative that reduces this risk.


Thurman, I think your point about rounded corners in an aluminum crescent is important, as you've had no problems with martins hanging. Most factory cuts are at an angle, so I rounded mine out a bit based on your discussion of this last year.

There always variables that may account for martins getting hung up. Maybe Steve has documented more cases because of intense competion for housnig in La., but if it happens anywhere, it concerns me. Maybe some holes are a hair too small. There's different grades of aluminum too and I think some houses use some that's a hair thinner -- maybe that's a factor.

I can't imagine not using some sort of SREH in Missouri, as we're swimming in starlings. I'll just round my crescent corners and open them up very slightly at the bottom, as Samuel says, doing what works for me.

I also suspect starlings are attracted in breeding season to the sight of a "big round hole" and maybe are less apt to investigate smaller ones.

John Miller,
St. Louis, Mo
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