I have put up a raptor perch last year and am pretty happy with it. I'm not sure that it is being used yet, but it has a good chance of bring useful to attract Buzzards to keep my vole population reduced in my growing area (see original thread here. My trouble is that, as I feared the fence post I knocked in to support the tall post is not up to the job of holding the post upright in our strong winds. We have only had a couple of winds of about 65mph so far this winter, but the post is now loose, with a gap in the soil allowing it to rock. As yet it is still vertical, but the situation is only going to get worse, and I don't want it falling on my new shed, also built this year and in the lee of the prevailing wind!
My soil is compacted silty loam on top of solid rock, which is only about 18 inches down at this location. The easiest thing to do would probably be to tamp a block of concrete around the post, but is there a better solution? The post will rot in time, and the concrete will then be just a lump, so not to my mind ideal as a use of resources.
I have more fence posts, smallish rocks and rope, wire etc. All suggestions welcome!
It doesn't have to be exactly like that, a water barrel filled with rocks and strapped to the pole, should do nicely, while also being a mini pond/bird bath.
If you were to dig down to the bedrock you could set the barrel right onto it, and berm all around it.
Cutting off both ends of the barrel, you set the post in the center and add rocks all around it , all the way to the top of the barrel
The stones in the barrel will drain water freely, keeping the post where it should be and in good shape.
You lose out on the mini pondr, but you do create reptile habitat...do yall have beneficial reptiles?
It doesn't have to be exactly like that, a water barrel filled with rocks and strapped to the pole, should do nicely, while also being a mini pond/bird bath.
...zip....
You lose out on the mini pondr, but you do create reptile habitat...do yall have beneficial reptiles?
Not much in the way of snakes, lizards are pretty scarce, slowworms are the most likely beneficial reptile which I have seen locally, although not at home.
As it happens I do have a spare water barrel, that turned out too tall for my shed guttering. I suspect cutting the bottom off and inverting it would be more stable, although it is not a big diameter.
If you have plenty of rocks, I admit I'd be inclined to go for a larger diameter than the barrel in the picture. You can make your own "gambion baskets" with used wire. Thicker wire like old chain-link fencing for the outside strength, and then smaller wire like chicken wire or hardware cloth on the inside if you need to use smaller rocks.
If you can't get cheap or free fence wire, you could try to get 4 pallets and wire/bolt them in a square and then fill them with rocks.
If you do get friends building a nest up there, that's going to add significantly to the wind load. Raptor nests can be huge.
Jay Angler wrote:If you have plenty of rocks, I admit I'd be inclined to go for a larger diameter than the barrel in the picture. You can make your own "gambion baskets" with used wire. Thicker wire like old chain-link fencing for the outside strength, and then smaller wire like chicken wire or hardware cloth on the inside if you need to use smaller rocks.
Actually that would be my preferred route I think: the barrel is still ept as a barrel (although it needs a plug/tap for the bottom hole) so it would be a pity to cut it up. I do have quite a bit of standard stock fencing that has several years left in it and can add more wire binding to fill in the holes if I feel necessary. Probably two layers, one upside down inside the other would do the trick. The lower levels of the fencing have smaller holes presumably to stop lambs jumping through.
If you do get friends building a nest up there, that's going to add significantly to the wind load. Raptor nests can be huge.
Yikes! I was only aiming at a hunting perch! I believe the buzzards (and eagles) nest in the hills hereabouts - there are steps in the terrain where there must be suitable ledges. I certainly see buzzards fairly frequently and just want to encourage them to make my growing area a preferred hunting ground to reduce the vole/mice problem in bad years.
If you made a large X out of heavy beams, snugged it up against the base of your post, so that the X is lying flat, and then bolted it to the bottom of the post in both directions, that seems like it would have to prevent the kind of excavation you're seeing caused by the wind. It would be sort of like the wide base of a stick-fan. But I don't know if that would be in the way of other stuff.
Oh yeah, a wire gambion would be a better use of materials and potentially more stable.
I was just sizing up from the way I do posts for buildings, from 5 gallon to 55.
I wonder, could you do season extension on top of a gambion?
Blacken the stones, and wrap the outside in clear plastic?
The x base would be less work but would expose the wood to the soil.
I would also want angled reinforcements between the base and pole.
Nancy Reading wrote:Yikes! I was only aiming at a hunting perch! I believe the buzzards (and eagles) nest in the hills hereabouts - there are steps in the terrain where there must be suitable ledges. I certainly see buzzards fairly frequently and just want to encourage them to make my growing area a preferred hunting ground to reduce the vole/mice problem in bad years.
I'm in an area without suitable cliffs, and our raptors use the tops of trees, particularly dead trees. However, humans tend to cut down dead trees, which is making it more difficult for many birds to find good nest sites. I assumed if you had plenty of raptor food, they would be interested in moving in. That may not be an issue in your ecosystem - didn't mean to frighten you!
William Bronson wrote:
I wonder, could you do season extension on top of a gambion? Blacken the stones, and wrap the outside in clear plastic?
Oh my, now you're talking! I'm all for function stacking if moving rocks is in my future!
We have a pretty cool summer, but I could see that a wall of rock would be a good heat storage for the sunny days we do get....Our sunniest period is in spring. One thing I am interested in trying is hops, if I could get them an earlier start that may help the tail end of the season, although the tops would be exposed of course still,I could use the perch to put strings up to give height for them to climb.
There are a few other plants I can think of that would benefit from a bit of shelter in my climate, like globe artichoke and asparagus. I'm thinking maybe extend the stones either side of the gabion to blend it in a bit....maybe a seating area....Thank you!
Nancy Reading wrote: One thing I am interested in trying is hops, if I could get them an earlier start that may help the tail end of the season, although the tops would be exposed of course still,I could use the perch to put strings up to give height for them to climb.
There are a few other plants I can think of that would benefit from a bit of shelter in my climate, like globe artichoke and asparagus. I'm thinking maybe extend the stones either side of the gabion to blend it in a bit....maybe a seating area....Thank you!
The fine line between "stacking functions" and "the little project that grew"!
Raptor perch 1.0 is sounding better and better as 1.4 version!
Jay Angler wrote:The fine line between "stacking functions" and "the little project that grew"!
Raptor perch 1.0 is sounding better and better as 1.4 version!
Haha! Yes I must think about all the stones I need to move before I get too excited. There are also a couple of little rowan trees in the area, so I'll need to take their location into account. I'll go down in daylight with my sensible glasses on and think about it in situ.
You are wanting to resist a torque. The torque is the product of a force and a lever arm. The lever arm is about the height of the pole and the force is the "windage" - the drag force the wind exerts on the pole. Right now, that is modest even in a strong breeze, because there are only some "crosstrees" at the top of the pole. But if a raptor builds a great stick-pile nest up there, the windage will be much greater. Starting out, you can consider a bare pole - this writeup is FAR more involved than we need, but gives you some quick reference: https://www.eng-tips.com/viewthread.cfm?qid=368082 - which if I guess the pole is 35 feet high and 6-inch diameter I calculate a torque (moment) of 715 foot-pounds - that is probably based on a hurricane force wind load.
If you want to resist that torque with supports at the base of the pole, you will need quite a bit of mass. If you want to resist the far greater torque that would arise from an eagle's nest, I think piling rocks is probably not going to be practical. Because solid rock is not far down, I think you will want to tap into that and add guy wires or ropes in three directions (unless you know the strong wind will always come from one direction). But if you don't, you probably don't have to worry. Raptors have a sense for this and won't likely build on a "shaky" pole. If you need help calculating for guy wires, I'll be glad to do some figgering.
Thanks for your link Cade, unfortunately I can't calculate in imperial, as I was brought up in metric (although still use feet, pints, ounces for home use!) I'm not expecting (or desiring) an eagle or buzzard to nest on the pole. I have only put a cross perch at the top (slightly offset) so I don't think they will be tempted away from the cliffs.
My pole is not as tall as that - probably 16 feet tall and 4 inch diameter, so hurricane loading would be a bit less than 300 foot pounds, I suppose. I did consider guy ropes, but I think they will be a pain to walk into (knowing me!). What I am thinking to increase the resistive moment at the base, is to put more cross beams inside the rock gabion (edit: modifying Christopher's suggestion above). I'm thinking that will maybe double the effect of the rock resistance, although the fixings will probably be a weak point. I've sort of sketched what I'm imagining.
At the moment the pole is leaning to the East as we have gusty wind from the West (up to 60 mph this week). On Saturday it was leaning about 20 degrees off vertical to the North, as we had gales from the South. Usually South and West are our strongest wind directions. I don't know whether it will survive long enough for me to complete the job - I'm just hoping it doesn't fall on my shed. Unfortuntely it is a bit heavy for me to lift it out of the hole, but I'm tempted to get an extra pair of hands and remove it for the next few months because I have too much to do outside at the moment.
I know you are dealing with more limited resources on the Isle, so I will try to keep my few suggestions consistent with that fact.
A pole, rounded on all sides will catch considerably less wind pressure than a 4 flat sided post. You can always use a draw knife to round off the corners of your post. That is not a casual amount of work, but I am assuming you are building this to last as long as possible.
Lash the cross beams to the main pole/post, rather than using screws or bolts. As this thing moves in the wind, the screws/bolts will eat away at their surrounding wood, drastically decreasing the lifespan of the structure. This is called cavitation and is the bane of wooden boats. You can use the same lashing technique that Wharram catamarans use. Easy and strong.
If you have access to any substantial driftwood, cut or burn a "just big enough" diameter hole completely through the mid point of a good sized log/beam, and stick the main pole/piece into that. Use a liberal amount of wood glue. Again, this won't be easy, but burying that will give you a lot more stability than just sticking a pole in the ground.
I might try a couple of diagonal braces - poles that are secured to the main post at about head-height and socketed into shallow holes in the ground about the same distance out from the post base. Setting a diagonal brace into the ground in an old paint bucket can give the brace some extra bearing area so it does not dig in so much. You'd want to put those braces in the downwind directions.
You can sieze these poles to the main post by wrapping rope around both the post and the brace pole several times without much concern for tightness, then taking several wraps around the first wraps but BETWEEN the pole and the post - pulling these wraps tight as possible to pull the first wraps together into the narrow gap between the pole and post. You can make a very tight seizing in that way. To finish it off, you can just make the last couple of wraps with a hitch - tucking the loose end of the rope under the previous wrap before pulling it tight.
why not drive t posts in even if you have to hydra jet them in place...
a 3 or four of those with dead man cables would allow good stability, adjust-ability and be very cheap.
Nancy Reading
steward and tree herder
Posts: 10946
Location: Isle of Skye, Scotland. Nearly 70 inches rain a year
Cade Johnson wrote:I might try a couple of diagonal braces - poles that are secured to the main post at about head-height and socketed into shallow holes in the ground about the same distance out from the post base.
I might do a modification of this. My main concern at the moment is that the pole might fall and crush my shed. You can see it in the photo in my top post. It might have been quick to make and free, but I'd rather not have to start again! I'm thinking that a single brace to the top of one of the shed sides would act as a pivot, so that in the worst case it would push the pole to one side or other, rather than on top of the roof!
Thanks for all the suggestions - keep them coming, even if they're not useful to me, they may be for someone else in future.
These are the larger of the rock jacks we installed. This spot we wanted the gate was bedrock. These 4x4x3.5ft rock jacks also provide the highest corner post for an 800ftx5ft fence, also largely on bedrock, so this is much heavier than a raptor post would require. We also did smaller rock jacks where posts could only be buried a fraction of the required depth due to bedrock. The half wine barrel pots on top do seem to get some residual heat from the rocks, keeping these winter peas happier. However, in the summer they dry out too quickly due to being too small and the wood wicking moisture. I have had better luck with grapes growing in adjacent raised beds then climbing over the trellis and benefiting from extra radiant heat from the rocks.
IMG_4997.jpeg
This is all just my opinion based on a flawed memory
Nancy Reading
steward and tree herder
Posts: 10946
Location: Isle of Skye, Scotland. Nearly 70 inches rain a year
Ben Zumeta wrote:The half wine barrel pots on top do seem to get some residual heat from the rocks, keeping these winter peas happier. However, in the summer they dry out too quickly due to being too small and the wood wicking moisture. I have had better luck with grapes growing in adjacent raised beds then climbing over the trellis and benefiting from extra radiant heat from the rocks.
I had thought about planting on top of the rocks. My climate is pretty damp, so the extra drainage could well give me an opportunity to try some bulbs that prefer a drier location perhaps.
The pole is getting more and more precarious at the moment!
For those that are concerned - the post is now safely on the ground. My husband kindly lifted it out for me yesterday during a lull in the gales while I was down at the shop (bless him!). He said a hooded crow was using it, not the birds I wanted to encourage but a start!
This will now be a summer project, since there are many other things to take up my time in the next few months, but after planting season things do seem to get a bit quieter. I think once an empty gabion is set up (I'm thinking of taking the silty soil out from under it now) I can just fill it gradually during the summer in stages, so spreading the rock moving out a bit.
Jay Angler wrote: our raptors use the tops of trees, particularly dead trees. However, humans tend to cut down dead trees, which is making it more difficult for many birds to find good nest sites.
Being an informed raptor lover myself, the dead spruce tree by the house has been topped so it can't fall on the house, and a few choice branches have been left so it resembles a cactus, hence its namesake. When the cooper's hawk isn't visiting in winter, the pigeons love it, and it is also fantastic for supporting an extension cord!
Nancy Reading wrote: One thing I am interested in trying is hops, if I could get them an earlier start that may help the tail end of the season, although the tops would be exposed of course still,I could use the perch to put strings up to give height for them to climb.
Hopefully you'll be wanting to harvest the hops. Using a ladder would mean to trust your foundations! Most growers go for dropping the wires/strings/whole structure.
I once came across an ivy hedge, that I discovered had a foundation of a former leylandii hedge. So while it may take a few years to grow, the cost of a leylandii cutting and a bit of time ring-barking will provide a perch, that'd hopefully last until the next cutting gets big enough. I've heard leylandii root readily from small cuttings.
Nancy Reading
steward and tree herder
Posts: 10946
Location: Isle of Skye, Scotland. Nearly 70 inches rain a year
Anthony Powell wrote:I once came across an ivy hedge, that I discovered had a foundation of a former leylandii hedge. So while it may take a few years to grow, the cost of a leylandii cutting and a bit of time ring-barking will provide a perch, that'd hopefully last until the next cutting gets big enough.
Awesome idea - apples for you! Growing a tree so that the pole itself grows it's own foundations would work perfectly! That is thinking four dimensionally!
I don't think I will here though - I'm not wanting to move all the rowans I've got in the area, but maybe I could review the positions of some of the spruce near to my polyculture areas (where the soil is, if anything, even shallower). I'm only using spruce because it is readily available from forestry plantations, leylandii also grows perfectly well here, although I've not planted any. It doesn't even take that long for the spruce to get to a reasonable height (depending on soil again), probably about ten years in a good spot. Maybe one of my other spruce just outside the area might be suitable in time...Thank you Anthony! .
I love the tree suggestion above. Before I take out any dead tree for fire mitigation, I try to consider its value standing. This includes snag habitat, as several times more vertebrate species live in snags than standing live trees. This makes a snag a natural fertility depository. I also think that rooted tree, alive or dead, is very likely to outlive the usefulness of any other wood post we might install.
This is all just my opinion based on a flawed memory
Ra Kenworth
Posts: 666
Location: Iqaluit, Nunavut zone 0 / Mont Sainte-Marie, QC zone 4a
Nancy I never thought of cross braces -- excellent idea! I had a good laugh about your leaning jack post of Skye!
If you divert runoff towards your spruce they will grow like weeds. I have some I used for that, for a windbreaker and I have moraine with 1" topsoil at 650' 4a
Thanks for the post. I have learned a lot.
Nancy Reading
steward and tree herder
Posts: 10946
Location: Isle of Skye, Scotland. Nearly 70 inches rain a year
I now have a rock filled gabion supporting my pole. In the end I excavated the soil down to the rock - the depth was probably less than 18 inches, so in my silty soil it was no wonder the post started leaning.
This was the hole as I was trying it for size:
In the end I used some other spare fencing with a smaller hole mesh:
filling with stones
I didn't take a picture of the cross piece I fixed to the base of the pole, but it reached almost the width of the gabion. This week I finished filling the basket with stones.
gabion supporting tall pole
The pole is now pretty sturdy - I can lean against it with all my weight at the bottom without it shifting at all, so I think it ought to be OK in the wind now!
supporting a tall pole on shallow soil
I left a bit of a hollow in the top of the gabion as a planter. I'm thinking I may try strawberries and herbs in there - I may be able to plant some alpines or possibly more strawberries in the rock sides as well.
In the photo I see what appears to be a trellis (or soccer goal). Why not put the perch behind the upper bar, foot in the ground and lash it to the up cross bar? Or similarly you have braced corner posts on the fence behind. Incorporate the perch into the the fence bracing. Multiple points of contact are going to provide better results than one. The perch is tall enough it would not be hindered by lower bracing. I see hawks sitting on fence posts all the time. They prefer higher, but have no problem utilizing a lower perch.
Jack Edmondson wrote:[Multiple points of contact are going to provide better results than one.
Good point, but all the objects you mention in my case are also without much foundation. The cross bracing you see on the fencing may be my access gates and the 'goal posts' is a bit of builders temporary fencing which I tie to a couple of poles as pea netting moving each year. I get away with it on these things because they have no real loading - no livestock to push down the fences, although the dogs do try and burrow underneath sometimes...
As regards attracting manure-providing wildlife - that deserves a thread of its own!
I found this great general one: fertility from visiting wildlife
Nancy Reading wrote: As regards attracting manure-providing wildlife - that deserves a thread of its own!
Wars were fought and people have died over guano! It's why it freaks me out a little how much human "output" gets contaminated by being mixed with industrial waste so it's too dangerous to use it as fertility despite there being a very long history of "Night Soil Man" dealing with it sustainably!
We have to pay to get our septic tank pumped out every 5 years (Municipal Regulation), but there was a time in ancient Japan when people got paid by a farmer for whatever remains he could dig out of the outhouse pit. Ritzier areas where the diet was generally better, could command a higher price even!
However there are also equally long histories of Humanure being used poorly, causing disease and particularly spreading intestinal parasites. That's still a risk today in some places.
However, when I saw you'd built a little garden at the base of your newly reinforced Wild Raptor pole, I couldn't resist the tease! As meat eaters, their guano should be a good source of phosphorus and calcium.
Nancy Reading wrote:
.....much rock moving later....
I left a bit of a hollow in the top of the gabion as a planter. I'm thinking I may try strawberries and herbs in there - I may be able to plant some alpines or possibly more strawberries in the rock sides as well.
top of gabion as planter
Will that encourage rot in the post? Being Skye, I'm assuming watering the strawberries will be unnecessary, as applied water is likely to drain straight through.
Nancy Reading
steward and tree herder
Posts: 10946
Location: Isle of Skye, Scotland. Nearly 70 inches rain a year
Hi Anthony. I'm hoping it will be OK. I did prop some stones up against the post, so there is not much soil actually in contact with the post - you might be able to see them in the middle picture prior to the earth fill. It will be no worse and probably better than the same post in the ground anyhow. I'm not sure where the pole came from. I think it was a sub standard floor joist from someone's refurbishment project. The wood is far better quality than what you would be able to buy now for that purpose though.
As you say watering is not normally needed (nature does that for me) and the soil will be well drained due to the rocks beneath. It might be that normal strawberries will need a bit more moisture if we get a dry spell, but I think they'll be worth a try.
Gabion support has worked great over the last year - no problems in the wind Unfortunately no buzzards yet. I haven't seen so many around this year at all.
I do have a few hoodies using the pole though, not exactly what I want to encourage .
Yes - but I was worried I was going to walk into them all the time So far I'm really happy with the DIY gabion. I get a little resonance in high winds, but the base is firm.
Hubby used these when he had to build a tall stack to 10ft scaffolding to lift 20ft long pipes out of our well. Then as is prone to happening around our land, the project stalled.
I added flagging tape, but it didn't survive contact with the geese in the field. I finally had to insist the stack be removed even if it meant rebuilding it later as the tripping hazard was just too great. I'd even observed the geese tripping over them.
Short term, cables are a great way to make something safe, but long term, one has to be very careful to position them so as not to be a problem.
5
Unfortunately no buzzards yet. I haven't seen so many around this year at all.
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