Bird Netting Materials and Techniques
POSTED IN For Consumers, For Growers ON 1/19/2016
The following post has been created to capture a talk given by Craig Cunningham, Harbor Hill Vineyard Services, presented to the Saskatoon Session at The Northwest Michigan Orchard & Vineyard Show, Wednesday, January 13, 2016
Vermin want to eat your fruit before harvest. Birds, rodents, and mammals are waiting for the perfect moment to gorge themselves on your investment. And why not? It is conveniently located, largely unprotected, and it tastes so good that consumers are willing to pay you just for the chance to have some of their own. Even an occasional human can be found foraging in the orchard. So how can growers protect their crop until the hour of perfection when the fruit is harvested?
I have tried pretty much everything, and the animals have the upper hand (or paw or hoof or claw) with pretty much every option. Flashy tape does not work. I have tried scary eyed balloons, plastic snakes, owls and other animal shapes, old spray suits, bird noises, cannons, avian control (on a 7 day cycle), four wheeler drivers with shot guns (I don’t recommend this for anyone) and, yes, even air dancers.
All these approaches make you feel better. But they don’t work for very long. You can mix, match, rotate, and move around each of these deterrents, but the birds will acclimate.
The only thing that really works is bird netting. Problem is that it is very expensive and very labor intensive. Be sure that it is cost effective before investing. Know the unit value of your crop and have an accurate yield estimate in any given year. Know your fields too, to better understand the actual pressure (damage potential). I have some fields with heavy pressure each year, and one field with almost no pressure.
Bird netting must be timely – just before the birds show serious interest, and until final harvest is imminent.
Bird netting is often reusable, though the quality of your netting, and the way you care for it, will have a lot to do with how long it lasts. I have some netting that is nearly 20 years old and doing well, though I tell my staff each fall to remove it as if their job depends upon it.
There are 3 types of bird netting that often relate to the durability of the material that they are made from, and reflect their potential lifespan.
- Black is often extruded polypropylene. This is usually the least expensive option, and the quickest to fail.
- Green [lighter more flexible HDPE] can tangle easily with bushes and debris.
- White is also HDPE, and is a heavier woven product. This is strong, flexible, and my preference for bird netting. I have had it last for over 10 years when used only during fruiting season, and well cared for year around.
Whichever system you choose, closure will be key to your level of success. Along every seam (where two pieces of netting meet) and around the full periphery (where netting comes to the ground or any other ‘terminal’ surface), full closure must mean no space for critters to get through. For net-to-net ‘seams’, you will want to find a way to ‘stitch’ the sections together, whether an actual weave of twine, or twist ties, or a system of solid objects such as skewers or plastic clips; hardware of this nature should be available from your netting source. For terminal edges, drape down to the ground and allow 1’ to 2’. Think this through for your unique property before investing in a system. Covering ‘almost everything’ is very close to covering nothing.
There are 2 types of bird netting strategies that help protect from varmints:
- Single Row Drape-over
With this strategy it is hard to get closure on periphery with varied bush heights. This is a good option for trellised grapes, because the trellis can act as a frame for the netting, though this is hard to work with because it is labor intensive. For some saskatoon cultivars the harvesting can come in stages. With this approach the netting would be removed to harvest, then have to be reapplied until the next harvest.
- Multi Row Drape-Over (Complete enclosure)
The best option for saskatoons is probably complete enclosure. This system, like building a net room around part, or all, of your field, requires framing to cover multiple rows of bushes. Make sure your enclosure is high enough not only for your plants, but for you and your trimmer, sprayer, harvester and any other tools and equipment you will use during the season. And plan for repeated access. Anchor your posts well, as containment failure (even temporary) is nearly as bad as no netting for the whole season. Between anchored posts you can run 12-gauge wire to hold draped netting, and even include temporary supports along the way. When the wire is tightened (assuming the anchored posts hold – this is a “must”: frame has to be adequately built to host netting) the temporary posts will be held in position if the wire is snug across the top of each support. Keep in mind that you are building a structure not just for sunny peaceful days, but also for stormy days and unexpected stiff breezes.
Net enclosures should be inspected regularly to check for inadequacies and failures.
The Costs of bird netting includes:
- Posts (primary)
- Temporary Supports
- Cement [maybe, for posts]
- Wire (12-gauge) – tightened after frame is assembled
- To install framing
- To drag netting over the framing (and recover later)
I use the white woven HDPE and recommend one supplier – Michael J Schmidt, Jr. of SPEC Trellising – http://www.spectrellising.com. And that recommendation comes without any finder’s fee for me. SPEC is not always the cheapest, but he knows what he has, what you need, and he is good with schedule.
Current Sizes and Pricing from SPEC for Woven, Polyethylene Netting
16.5 x 990 $425/bag
21.5 x 990 $550/bag
33.0 x 990 $900/bag
48.0 x 990 $1375/bag
66.0 x 990 $1800/bag
This product can go back in the bag at the end of the season, and be ready to use in the spring with no winter/moisture deterioration.
I encourage you to employ the various options before buying netting. Some sites have no bird pressure. Don’t assume netting is the way to go for every site. Make sure netting is cost effective. Really. Don’t do it because it sounds like a good idea, but won’t result in increased net income [no pun intended].
In some cases, the pressure is mostly along the edges and one might try limited border applications, but this can fail if species scout beyond the covered area.
Dogs help. Any type of non-recurring activity will help. The Swiss use monofilament, as do some in the Grand Traverse area. This product is often used for seagulls. I prefer the netting.
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