bird netting enclosure

TucsonKen
1283100610

I've been wanting to do this for quite a while, and am finally getting started on a bird netting enclosure large enough to protect figs as well as several other non-citrus fruits (the birds don't bother the citrus). I had put it on hold when I couldn't find an affordable source of netting with really small openings, but have decided to go ahead with a commercial mesh that's 5/8" x 3/4". We have one tiny bird species (verdin) that can squeeze through it, but it should stop all the others. Fig beetles can fit through as well, but I'll have to live with them.

Cost is a big concern right now, so everything has to be done for very little $$$. A low perimeter fence of salvaged chicken wire will keep the rabbits and javelinas out (the posts are salvaged 1/2" x 1/2" square steel rods, but rebar would work just as well). The "footprint" is 120 feet by 28 feet (with a corner cut off due to a power line easement), and the height will be 12 feet at the center ridge and 9 feet at the edges. The "tent" part will require about thirty 10' lengths of 3/4" EMT conduit, about 1000' of tie wire, and a 400' x 14' roll of bird netting ($123 plus shipping from http://www.amigoni.com/bird%20netting.htm).

Since I'm enclosing existing trees (persimmon, apple, 2 peach, 2 apricot, & 2 plum) I'm stuck with a layout that isn't the most efficient, but there should still be enough room to plant several of my UCD cuttings and other potted figs in the ground this spring. I'll post progress shots as I work on it.

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satellitehead
1283113094

Very cool. Please do keep this updated, with pics, I'm very interested to see what you come up with, now that I'm having problems with birds also.

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snaglpus
1283138280

This good news Ken. thank you. I am planning on planting 40 trees this year and need at least 100 yards of netting to protect my trees next year. thanks, Dennis

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TucsonKen
1283144715

Dennis & Jason--
I'm glad my future fig-fortress may end up being useful to other bird-plagued fignuts. I'll definitely post updates as it comes together. The framework for supporting the netting should be a very economical way to enclose a large area--I just hope it turns out to be as easy in reality as it looks in my imagination!

One thing I still haven't worked out--does anybody know of a cheap, UV-stable string or light twine that would work for splicing adjacent sections of mesh together? The plastic twines I've tried end up disintegrating after a year or two of desert sunshine.

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noss
1283158751

Ken,

What about fishing line? I've had windchimes that are rigged with fishing line that seem to still be going strong.

noss

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genecolin
1283163642

Ken, Vivian is right. That new braided fishing line is stronger than anything else on the market and will last for years. I've been fishing with some for 4 or 5 years and its still as strong a new.
"gene"

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TucsonKen
1283172484

Thanks, Gene and Noss. Fishing line sounds very promising--I'll see what I can find out about how it holds up to constant sunlight. If it's UV stable, it would be ideal.

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noss
1283235321

Gene,

Do you find the braided line is mor UV resistant than the regular line. I cannot, for the life of me think of what it's called... Oh monofilament?

I'm glad to hear how long your braided line has lasted for you. We just started using it when the watergrass was cutting the monofilament lines we had.

noss

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TucsonKen
1284310764

UPDATE 12 Sep 2010
It's now cleared and fenced. This view is about midway along the south side, looking east. Posts are about 7'-6" on center. The little shed at the far end is an old playhouse that I relocated for keeping pots and stuff. The thing to the right of it is a compost pile.

Next I'll rig the post-and-wire framework that will support the bird netting. I will probably wait until spring to install the netting, though, since there's nothing that needs to be protected before then. I looked at Home Depot's EMT conduit, and although I had planned to use 3/4" diameter tubing, I think 1/2" will be strong enough--for about half the price. It's less than $2 per 10' length, so I should be able to get all the posts for less than $60, plus tax.

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TucsonKen
1286385701

UPDATE 06 Oct 2010
The basic framework is up, using 1/2" EMT electrical conduit posts to support a 14' x 15' grid of rebar tie-wire, which will hold up the plastic bird netting. (Post spacing is 15 feet on center down the length of the enclosure, and 14 feet on center across the width.) Please note that there are power lines and phone wires visible, which aren't part of the framework.

To avoid having anything stick up above the wire support grid (where it might snag the bird netting), I drilled four holes in each post, roughly an inch and a half from the end, so that wires could be mounted by threading them through the end of the post and back out through one of the drilled holes. To make it easier to thread the wires, I "flared," or angled, each drilled hole with an old nail-set:

To keep things as cheap as possible, I secured each wire by wrapping it a couple of times around a "hog ring", and then crimping the C-shaped ring to form a tight "O". This creates a stop, so the wire can't be pulled back through the drilled hole.

(A more expensive, but better approach, would be to use threaded cable clamps, which can easily be removed if adjustments are needed. Stainless steel cable would be better than tie wire, and abrasion to the bird netting could be reduced by sleeving 1/4" irrigation tubing over the cable.)

I measured and laid out much of the wire grid while the posts were still lying on the ground, and then raised them all up and made the final crimp-connections from a ladder. (This was necessary because I had to work around existing branches; if someone was starting with bare ground or very young trees, they could make all the connections at ground level before raising the posts.)

The bottoms of the posts simply rest on the ground and do not have to be anchored (although once I install the netting I'll put a piece of brick or tile under each post to keep it from settling into the ground); everything is held in place by the tension of the wires, which are secured to the chicken wire fence. Tension on the wire is increased by moving the bases of the angled perimeter posts closer to the fence. (Although I don't much like the look of the angled posts, I chose to install them this way due to space limitations. Doing so will allow the netting to hang straight down at the perimeter, while avoiding any "shear" stresses on the posts, which aren't strong enough to resist any significant lateral force. With this arrangement the only stress on the posts is compression, and the weight they support is quite minimal. It would have been possible to keep all the posts vertical, but I would have had to move the fence out about 3-4 more feet, and I just didn't have enough room.)

The posts that support the central ridge are 12 1/2' high, and vertical; to get the extra height I used a coupler (see below) to splice a short piece to each standard 10' length. The perimeter height is currently 9 feet (10' post at an angle), but once I install the netting, I may be able to raise this a little higher, if there's enough overlap between netting and fence to allow it.

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genecolin
1286411600

Ken, looking forward to your pictures. I need to improve on my bird netting next year and want to look at all possible solutions. Thanks for the update.
"gene"

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TucsonKen
1286418206

Gene-- My son showed me a different way to include the photos, so I was able to go back and add them to my previous post. Hopefully, they will illustrate what I was trying to describe.

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genecolin
1286446173

OK now I understand, pretty simple. That's gonna be a big birdless cage. I won't need one that large for the coming year but I do have to make mind larger and stronger. Thanks for the ideas and the source of the netting.
"gene"

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TucsonKen
1303840529

UPDATE 4 April 2011

Finally! A bird-free zone!

I still have a few minor details to wrap up, but the "anti-aviary" is virtually finished--just in time to save most of the apricots, as well as all the peaches, apples, plums, and persimmons. My feathered freeloaders start pecking the green apricots when they're only about the size of my finger tip, so they've already gotten a few, but hopefully that's the last they'll get from now on!

After the low, chicken wire, perimeter fence was in place, but before installing the bird netting, I noticed little hoof prints in the dirt along with signs that a javelina had been rooting around for melon rinds in the compost under the Fuyu--evidently it shoved the top of the wire down just far enough to topple into the enclosure. Fortunately, it didn't bother my figs. I reinforced the fence here and there but it kept getting in, night after night, so I resurrected my old "Fido-Shock" electric fence charger and added a series of four hot wires, just outside the chicken wire, as a little extra deterrent. So far, so good.

If I had it to do over again, I'd scrape up the money and buy new chicken wire, or better yet, 1/2" galvanized hardware cloth, for the perimeter fence. I also think I should have used 3/4 inch conduit instead of 1/2 inch, although it's already made it through some strong winds with no problem. I also wish I had rigged the netting support with the same 17 gauge galvanized wire I used for the electric fence--but the tie wire should still be fine. Splicing the netting together was a much bigger job than I had anticipated (two long seams for a total of approximately 260 feet of hand "stitching"), but 14 feet is as wide as it comes, so there was no way around it.

I had been thinking of keeping chickens inside the cage as well, but I also want to use it for growing squash, tomatoes, and other vegetables. My wife pointed out that chickens would gobble the veggies as fast as I could plant them, so I guess the chickens won't work out after all. Too bad--I was looking forward to having some.

The newly-planted figs seem to be growing nicely, although leaf-cutter ants (another plague for Tucson gardeners) attacked my Black Madeira. They couldn't snip through the thick petioles like they do on most trees, but they still managed to chew up all the leaf edges. Oh well--no real harm done.

All in all it has been a very cost-effective and fun project, and I'm optimistic it will work out quite well. I'm really looking forward to eating a lot of figs in a few years!

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FrozenJoe
1303849266

Very impressive Ken. It looks like you've put a ton of work into that enclosure. Wish I had something like that!

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loslunasfarms
1303850097

Where do you purchase your bark?

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TucsonKen
1303851833

Thanks Joe. If you ever decide to build one, I'd be happy to share any info or give you a rough idea of materials cost based on the size you want. I think it could be easily adapted to most any scale.

LosLunas--it's actually just mulch that a local landscape service delivers at no cost if he's working in the area and it happens to be my turn (there's a long waiting list), along with my own prunings that I run through a little cheapo electric chipper-shredder from Harbour Freight.

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Chivas
1303853232

That is a very beautiful set up you have, thank you for sharing it and going through the step by step, I hope it works well for the season and those to come.

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paully22
1303868655

Excellent job Ken. Shall let my brother know about your neat netting job. He has a serious bird problem.

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noss
1303876800

Hi Ken,

What did you use to sew the netting on/together? That enclosure looks great! What a good job you did with it.

noss

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TucsonKen
1303880405

Noss--I found a local awning manufacturer willing to reel off three hundred feet of UV resistant, high-density polyethylene thread--basically the same material and thickness as the netting.

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JD
1303935253

Very nice Ken. It gives me some ideas for a scaled down version to protect my blueberry and figs this season.What are you using at the tops/tips of the 1/2" emc to support the netting and stabilize the emc via the wire?

JD

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TucsonKen
1303945198

Hi JD--

I had posted photos back in October but they disappeared, so here are some that should illustrate it pretty well.

First, I drilled holes in the EMT to thread the wires through. Then I flared them (if that's the right word) with a nailset to make it easy to fit the wire through the hole by feeding it into the open end of the EMT. At this point, all the poles are lying on the ground--I simply measured and cut the wires, and then made a sharp little bend where I wanted it to meet the top of the tube. The whole grid of wires was laid out and connected at ground level. To secure the wires to the EMT, I wrapped each wire once around a hog-ring (positioned to act as a "stop" to prevent the wire from pulling back through the hole), and then crimped the hog-ring to secure it. (I would advise clipping the loose wire ends off at a couple of inches rather than leaving them long the way I did, and that way the ends won't catch in the netting as you're installing it.)

I connected the end of each perimeter wire to the perimeter fence and then raised the poles up one by one, just like pushing up a tent pole. The grid of wires, anchored at the edges to the fence, is all that holds the tops of the poles in position, and the bottoms just rest on the surface of the ground (or on bricks, rather, which prevent the poles from sinking into the ground when it rains). So, there's no "shear" force on the poles at all--it's strictly a very small compressive load consisting of just enough tension on the wires to hold things in place, and the negligible weight/wind resistance of the netting.

It's especially convenient if you need to reach up to the netting or the top of a pole for some reason, because all you have to do is lift the bottom of the pole a few inches off the ground and swing it out, which drops the top down to where you can reach it, and then put it back in position. Easy to build, and easy to maintain. I was able to erect the whole framework right over my existing trees, and then pull the netting up over the top with almost no need for a ladder.

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goldie
1304183992

I can't wait to show my husband! Great job.

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TucsonKen
1305825296

It's SO NICE to go out and see fruit ripening with no bird bites! I love it! There are lots of persimmons and peaches, but far fewer apricots, apples, and plums. I don't know if it's lack of bees, wrong pollinator trees, poor soil, inadequate pruning, or what, but at least the fruit that does set gets a chance to develop, and now I can focus on figuring out how to improve yields instead of battling birds, javelinas & coyotes.

The cage is also home to ten little in-ground figs with room for about six more. The few veggies planted here and there have been growing nicely as well, now that the quail can no longer nip them off as soon as the first tender shoots break the surface.

The black plastic around the perimeter is to keep out smaller birds that can squeeze through larger wire (1 1/2" stucco mesh) that was used in some sections. If I had done it right, with a 3' high perimeter fence of half-inch galvanized welded wire, the plastic wouldn't have been necessary, but hey--live and learn.

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