Owl cage for Troyes Gemini Gourd Racks?

[Spiderman]

Anybody ever build one?

To make it more complex all the gourds are Troyer Horizontals. Cage would be 8’ wide at least.

Had some Great Horned Owls here this year and I think a cage is the only way to defeat them.

They killed too many Martins to ignore it any longer.

[flyin-lowe]

Thats tough, it might be easier to some how rig up a section of cage in front of each gourd... I keep waiting to start having owl issues at my place but so far have avoided it.

[John Barrow]

Spiderman,
I have not used the Gemini systems believing that they would be difficult to fashion a cage for, should owls become a problem while using them. Late in 2021, Kentucky landlord Mike Brown posted a system that he designed for his Gemini systems that appear to be a great step toward protection. It is posted on Purple Martin Conservation Assoc.'s group Facebook page. You can find the post by searching on their page for "Mike Brown owl guards". Here is a link to the page down at Dec 31, 2021 https://www.facebook.com/groups/8089668 ... l%20guards (the copied link I posted contained double spaces where %20 copied out)

In addition to pictures of what he developed, the following explanation is included:
"Simple easy homemade Owl guards for the Gemini rack using 1\4 inch threaded rods two feet long. The holes already in the Gemini ring make it a snap. I used a whiz nut on the outside and a nylon locknut and washer on the inside. It will never come loose! Then simply bend the rods down in a radius like you see in front of the gourds. I got ten foot sections of the threaded rod for five bucks each at Lowe's in the electrical section. 10 rods will give you 50 two foot sections and you need 48 total. I cut them two feet long in a vise with a hacksaw. So for $50 bucks plus some whiz nuts and nylon locknuts you can easily Owl guard a Gemini rack. Bluebird Ridge colony in east Daviess County Kentucky." As posted by Mike Brown

This represents the best solution I have seen for fashioning owl protection on a Gemini--a cage, imo, would be challenging to construct. Having had success thwarting owl attacks using owl guards on AAA systems, I would recommend using longer and deeper guards (30 in vs 24 in). This type of system would also enable attaching fencing to the prongs if that became necessary--as a second alternative to a cage. (My guards are shown in my post in the comment section to Mike's post.)

Wishing you best of luck. Please keep us informed of your progress.

[ken buker]

Spiderman,

I only have a few Troyer horizontals, I've mostly moved to the verticals and have fabricated individual very effective owl protection for the verticals.
Fabricating a cage for the Gemini I think will present a real challenge. However, some of my Troyer horizontals have extended tunnels and are equipped with the Troyer tunnel owl guards. I find these to work reasonably well, but not as well as my self designed ones. Troyer vertical gourds are equipped with the tunnel so the owl guards attach to them as well.

I believe modifying your horizontal gourds and equipping them with the Troyer designed owl guards would be as effective and less costly then trying to build a cage.

My Silver Lake Washington colony has been 112 pair strong over the last few years. My 8 racks are either equipped with cages or each gourd has it's own cage or owl guard protection at the entrance. My colony was nearly wiped out in 2006 by owls so I desperately had to come up with some type of protection. I still have some minimal loss and I occasionally observe owls perching above the cages at night but all and all, I have more difficulty with hawks particularly during fledging.

Ken Buker

[Thomabear]

I don't have any experience with individual guards, but I can say the cage I built around my 12 room Goliad was only marginally effective. My observations were that the martins were still exposed and taken during dusk attacks because they preferred to perch on the cage rather than the porches therefore transferring the problem to the cage. (see pic) Once they retired for the night and were in their houses the cage then helped.
After losing a couple martins from the cage I got to thinking about individual guards but never got around to it because I thought the birds would perch and be plucked from that as well. Then I got to reading about Owls flushing martins out of their houses by beating their wings against the doors and waiting for martins to exit to their death. I then became interested in the Chirpynest concept as a house design which allows the nest to be recessed far back and well below the entrance. This year I had a GH Owl make his move on the 24 Chirpynest setup I installed. I witnessed via my security camera his relentless, lengthy and failed attempts to flush out a single martin. I think the martins realized even more security after that encounter and the Owl eventually moved on as the result. My conclusion was that the long reach and recessed nest pocket well below the entrance allowed the martins to feel more secure which resulted in them staying put. I'm not here to advocate for one product over the other but I thought this observation was very interesting and worth sharing. Since then, I gave away my Golaid house and will be 100% gourd racks this coming season. I will not be adding Owl guards as I feel confident and will learn from this setup on the fly. My philosophy is to not implement a solution in search of a problem, especially when the solution becomes more work in the long run. I will however monitor my colony closely with the camera and will be ready to take action should it become necessary.

Owl Cage.jpg (54.41 KiB) Viewed 6409 times

[Dave Duit]

I hope these pics will show in my post. The round cage has a diameter of 10 feet. The roof is made of corrugated roof, white on top, black on underside.
The roof will last many many years. The roof is secured with metal flat bars on the underside and welded to the circle which is then welded to metal rods extending to a cap which goes over the top of the pole. The cage is hung around the circle with hose clamps. The gourd rack goes up and down freely and the floor section is suspended via cable wire. The floor and rack fit snug to the bottom of the cage when cranked up. Sounds like too much to get a persons head around. But, in short it is a huge huge project. The cage is called goat fence and has a mesh of 4 X 4 inches. The perch around the top of the cage is split pex tubing with split facing down and snapped around the very top of the fence and secured with zip ties. At least a person can get some ideas from my owl cage. Martins have no issues flying in and out of the cage. Gourds are about one foot from the cage. The small rectangle shapes on the cages in front of the gourds are prop tail perches. The martins land on these prop tail perches prior to jumping to the porch of their gourds. It is an added bonus around feeding time. When each parent comes in with a bug and if the other is still busy on the porch, the first parent just waits for their mate to leave for the next bug.

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[Dave Reynolds]

I hope these pics will show in my post. The round cage has a diameter of 10 feet. The roof is made of corrugated roof, white on top, black on underside.
The roof will last many many years. The roof is secured with metal flat bars on the underside and welded to the circle which is then welded to metal rods extending to a cap which goes over the top of the pole. The cage is hung around the circle with hose clamps. The gourd rack goes up and down freely and the floor section is suspended via cable wire. The floor and rack fit snug to the bottom of the cage when cranked up. Sounds like too much to get a persons head around. But, in short it is a huge huge project. The cage is called goat fence and has a mesh of 4 X 4 inches. The perch around the top of the cage is split pex tubing with split facing down and snapped around the very top of the fence and secured with zip ties. At least a person can get some ideas from my owl cage. Martins have no issues flying in and out of the cage. Gourds are about one foot from the cage. The small rectangle shapes on the cages in front of the gourds are prop tail perches. The martins land on these prop tail perches prior to jumping to the porch of their gourds. It is an added bonus around feeding time. When each parent comes in with a bug and if the other is still busy on the porch, the first parent just waits for their mate to leave for the next bug.
owl cage round.JPGowl cage square.JPG

..
.
,,,, Good Job Dave,, It looks like it would be effective... The Martins there have a great Landlord..

Dave

[Dave Duit]

Thanks Dave. I'm looking forward to the 2023 season.

[Spiderman]

Thank You Dave for the post!

I’m going to start on the round cage Monday, 10’ wide.

Have a couple of Martin landlord friends that will help me.

If you watch your Martin housing between sunset and dark, you will observe the owl pick off martins at last light. Great horned owl here gets at least 20Martins a year.

I have 82 gourds and average 75 pair each year, when you have that many Martins at one site they attract a lot of predators.

[Spiderman]

Martins murmur all night long.

The owls are drawn to movement and sound. They don’t get that big by being unsuccessful predators.

I also have wood duck boxes and had to reduce the amount of nesting material so the owl couldn’t reach the female at night.

But I really appreciate each of you that replied to this topic!

[Matt F.]

Missouri landlord Kathy Freeze compiled some amazing information including videos about a GHO that was attacking her colony.
Here's her blog page that also contains the YouTube video showing her owl protection, and how it's setup:
https://kathyfreeze.blogspot.com/2021/0 ... artin.html
Though not installed on a Gemini rack, it may help with some ideas.

[Spiderman]

Thanks for the link to Kathy’s video regarding hawk attacks and all that the other Members here that added pictures and information that was useful.

On the Gemini system just the wire for the cage will weight a little over 40 pounds.

Owl is already here dusk and dawn, will start constructing the cage in a few days.

Currently have more than 80 Martins all residing in Troyer Horizontal Gourds.

[Daryl Lindstrom - MN]

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Several years ago I had evidence of owl predation. I built owl cages for all of my setups. Knock on wood... no evidence of owl predation since. I used aluminum angle arms and goat fencing to assemble the cages.

[Spiderman]

If you have Owls or think you may have Owls this is a valuable link to cage building.

https://www.purplemartin.org/uploads/me ... mo-408.pdf

We built a cage around our three Troyer Gemini gourd racks with horizontal gourds. It added about 50lbs of weight to the three inch pole. Cable is 3/16” and winch is rated for 800 pounds.

From porch to porch the gourds are 8’ across. The cage is 10 feet. I have not added the wire roof yet, letting the Martins adjust to going through the 2” X 4” openings but they are doing good. Will start on the roof next week. Can still do nest checks from inside the cage just like before. Cage raises and lowers with the gourd rack.

We have about 80 Martins so far and expect about 70 more. They will start laying eggs around April 15th.

If someone would provide a free website where I can save pictures, I’ll create an account and upload some photos?

[brokensword]

I don't have any experience with individual guards, but I can say the cage I built around my 12 room Goliad was only marginally effective. My observations were that the martins were still exposed and taken during dusk attacks because they preferred to perch on the cage rather than the porches therefore transferring the problem to the cage. (see pic) Once they retired for the night and were in their houses the cage then helped.
After losing a couple martins from the cage I got to thinking about individual guards but never got around to it because I thought the birds would perch and be plucked from that as well. Then I got to reading about Owls flushing martins out of their houses by beating their wings against the doors and waiting for martins to exit to their death. I then became interested in the Chirpynest concept as a house design which allows the nest to be recessed far back and well below the entrance. This year I had a GH Owl make his move on the 24 Chirpynest setup I installed. I witnessed via my security camera his relentless, lengthy and failed attempts to flush out a single martin. I think the martins realized even more security after that encounter and the Owl eventually moved on as the result. My conclusion was that the long reach and recessed nest pocket well below the entrance allowed the martins to feel more secure which resulted in them staying put. I'm not here to advocate for one product over the other but I thought this observation was very interesting and worth sharing. Since then, I gave away my Golaid house and will be 100% gourd racks this coming season. I will not be adding Owl guards as I feel confident and will learn from this setup on the fly. My philosophy is to not implement a solution in search of a problem, especially when the solution becomes more work in the long run. I will however monitor my colony closely with the camera and will be ready to take action should it become necessary.

Owl Cage.jpg

your pic (the one with a bottom to the cage) is exactly what I've been asking about; I WAS going to put a bottom just as you have but thought PMs dive down when trying to escape? So, did you notice any issue with this behavior? I figured it might save any jumpers and keep them close by where the parents can still see them. Your thoughts?

[Spiderman]

I have Troyer horizontal gourds which are deeply recessed, but the Owl would land on the porch and beat his wings against the gourd and was successful more times than he failed.

Last year he broke the collar that holds the porches on four of the gourds.

I found five owl pellets last week that were all Martins, reason for the cages.

If the Martins hang on the outside of the cage that is beyond my control.

But game cameras are very valuable if you have a very sizable colony.

[Thomabear]

your pic (the one with a bottom to the cage) is exactly what I've been asking about; I WAS going to put a bottom just as you have but thought PMs dive down when trying to escape? So, did you notice any issue with this behavior? I figured it might save any jumpers and keep them close by where the parents can still see them. Your thoughts?

That cage doesn't have a bottom. When I was using it (I no longer do) the birds exited mostly through the wire and occasionally out the bottom. I no longer use cages, due to the additional weight and horizontal cycling stresses to the pole. I have since switched to housing that provides good owl protection. Knock on wood but I haven't lost a single bird to an owl attack since.

[Spiderman]

We have completed the cage for one of our three Gemini gourd racks. Used 1&1/2” 1/8” thickness aluminum angle to add length to the existing supports. Cage is 10’ across. Attached 2”X4” wire cage around the perimeter, 5’ tall wire. One piece was 33’ long. So it has eight contact points. It weighs about a pound per foot, so heavy.

Added 2”x2” soft netting to the top and bottom. The netting is used for batting cages in baseball. The bottom piece will need to be released to perform nest checks so it is not an ideal solution. Used zip ties and will need to replace them as nest checks are done. Soft netting piece I bought to work from was 9’6” X 82’ long.

Martins adapted to all the changes ok. They mastered the wire in a few hours and bounce when they land on the soft netting so they quickly learned they have to exit through the wire sides. Last night was the first night game cameras revealed there were no owl visits to the gourd racks. Owls have been here every night for three weeks. Lost a lot of Martins.

Yesterday a Cooper’s hawk was chasing a Martin. Martin entered the cage on one side flew through and exited the cage on the other side. Hawk stopped before he hit the wire and hovered like a hummingbird trying to understand where the Martin went. So probably saved a Martins life.