Every summer several pairs of ospreys nest and rear their young in the trees surrounding our cove, which is wonderful.
What is not so wonderful is that expensive sailing instrument wands seem to be their preferred place to perch while looking for fish to swoop down on, as can be seen in the above photo of a neighbouring boat.
I was having a similar problem with purple Martins in my marina. Dozens of them would perch on several boats mast tops and shrouds. Their “poop” is very unsightly. I had a pool noodle that came with the boat and I hoisted up the main halyard (don’t forget the retrieval line). It worked like a treat! Simple and cheep!
-Bill
It sort of waves around in the breeze and seems to discourage them. I tried it on a lark and being frustrated cleaning poop off the deck 🙂 Maybe there were other easier targets as well.
Ben Garvey
October 23, 2025 2:44 pm
Thanks for this John – I will be copying this install. I currently have no wind indicator for exactly this reason- I’m on my 5th one now – the bloody ospreys are relentless!
Glad it was useful and hopefully it works as well for you.
Wilson Fitt
October 23, 2025 3:29 pm
Hi John. Yes, an old VHF antenna wire sticking out at about 45 degrees over the radar scanner has kept seagulls it off for several years. But this year, for the first time, a gull perched on our bow pulpit rail and covered the roller furling drum in guano!
Cormorants are the worst of all. We went through a period where they were perching on the spreaders and covering the decks with the most disgusting mess of half-digested fish remains. Running the halyards from the masthead to the rail so they bisected the spreaders seemed to deter the cormorants and, although very plentiful around here, they have not fouled our nest for a couple of years.
Cormorants are strange beasts with foul habits. I was told that the aboriginal peoples called them “sea snakes”. Around here they have a penchant for invading small offshore islands in large numbers, roosting in the scraggly spruce trees, covering everything with guano that eventually kills all the vegetation leaving nothing but bare skeletons behind.
John Milton in Paradise Lost tells how Satan, when he decided to investigate what was going on in Eden in preparation for disrupting Paradise, disguised himself as a cormorant and flew in to reconnoiter the place. Milton was not much of a humorist, but I laughed out loud at that.
Yes, the cormorants are truly horrible. I had problems with them roosting on the spreaders on the M&R 56 and the solution was the same.
Matt Marsh
October 23, 2025 4:44 pm
Around here we get birds building nests in booms. Obviously you can’t do much once they’ve nested in there without harming them or the chicks. Chunks of packing foam wedged in the open ends of any uncapped spars seems to be the best deterrent.
Bryan Keith
October 24, 2025 2:36 am
Again the incredible neatness of your epoxy work amazes us.
We use one of the Owl statues. The key seems to keep moving it around so the Osprey don’t get comfortable with its inert behavior. We added a pvc pipe out the bottom (secured with expanding foam). This allows it to be hoisted like a pigstick on the pennant halyard or to be placed in a rod holder. Every time I check on the boat I change it’s location. We are on a dock so I also pvc rod holders on pilings.
Thanks, I always wondered how effective those owls were.
Charles Starke MD
October 27, 2025 10:04 am
I have a pigstick with a burgee flying on top of the mast. The pigstick has a full set of zip ties for 360 degrees around the stalk at different heights. They can’t land anywhere on top of the mast. I also have zip ties on all the spreaders sticking up so there is no place for them to land. My neighbor put a wire 2” above and parallel to his spreaders from the mast to the stays.
I mounted an anti-lightning static dissipator on my Sabre 38 to make the masthead less inviting to Chesapeake-based osprey. It has worked well. (I have the short version of the Raymarine windvane transducer arm so not too much room for a perch off the masthead.) And I have not had a lightning strike either, though I know that’s the subject of a different thread.
Thanks for the tip, always nice when we get an unexpected benefit from a piece of gear.
Edward Sitver
October 27, 2025 11:49 am
I installed a row of “spikes” along the boom by twisting on seizing wire. That was after my second repair from Osprey induced damage. The standard spike on the Windex and my VHF antenna seem to keep them from perching on the crane.
~Ed
Steven Klegman
October 27, 2025 12:42 pm
Here in Michigan, it is the cormorants that are the offending avian agents. I took a 1 foot piece of clear plastic hose, split it lengthwise and pushed multiple small nails through it and zip-tied it to the horizontal arm of the wind transducer. This has effectively deterred the birds for years.
Sounds like a good variation and probably easier than mine.
Bill Harvey
October 27, 2025 1:37 pm
Tied fishing line sbout 4 in up the ariel to the base of windvane arm
We also have a problem with seagulls building nests on deck
My boat neighbor saw them starting to build one on my boat so shooed them away ,about 6 seagulls then dive bombed him on his boat for days
Autopilot isn’t quite functional yet. It’s my first digital wind instrument and i do worry about the variability of the input. I think I’ll have to add a bit of smoothing on the data. I’ll update in the spring
Aaah, We’ve had to deal with all the prior mentioned bird issues for many years at our YC. If leaving the boat on a mooring for anytime more than a few days in August we strangle the deck with hanging shiny tape to keep the terns from crapping everywhere. Living and staying aboard is the best prevention.
Our solution for mast-head ospreys for the last 5 years is also an ultrasonic instrument. Too small and slippery to land on. (Garmin/airmar. I found the Maretron to be less reliable). We’ve logged several thousand ocean miles using all the autopilot modes including wind vane. Working very well. Only caveat is making sure the sensors stay clean. I need to climb up and clean at least every six months with mild dish soap and water. Otherwise we get irrational wind speeds, especially when rainy or foggy.
Thanks for the fill on ultrasonic use for feeding autopilots. Great to hear it works.
Dan Tisoskey
October 27, 2025 6:00 pm
Osprey are really cool birds of prey when watching them fish in the wild. Two years ago, I decided to sleep onboard with the hatches open (I sleep in the main cabin area on my last boat, 32′ Downeast) When I awoke, I had blood and other unknown objects on my chest! I thought I coughed up a lung during my sleep. When I looked up and out of the hatch, I found an osprey siting on the spreader (this boat has wood spreaders and they love to sit on them) tearing apart a bunker (menhaden) and dropping parts through the hatch.
Cleaning up the bunker parts and blood on the deck took hours! Much harder than seagull waste. I now have aluminum spreader and they avoid my boat.
I thought about that but I don’t think it would be stiff and springy enough, but I could be wrong.
Drew Frye
October 28, 2025 11:08 am
Bald eagles are a problem here. I had a VHF antenna, like the deterrent in the lead; they bent it over double. They ate two Windexes within two weeks, not just raining the plastic bits on deck, but wrapping the indicator wands like a pretzel. Far more destructive than mere ospreys, which I have lived with for 40 years.
I’m using ribbons on the shrouds (on a tri they are far from the sails and read true) until they go away.
The cormorants had moved in when I was at the boat yesterday. For some reason minnows were schooling around my end of the marina. Messy, but at least they don’t break anything.
I think I’ll try the noodle. Something like a spinnaker halyard and hoist it semi loose in the fore triangle? The line goes through the noodle, or some other way? Seems like it would chafe where the line moves in the head block? I have two spin halyards; I suppose I could reeve a cheap line in one of them.
(I Googled this–It says orange noodles attract Baltimore orioles, which are common around the water here. Maybe chartreuse.)
We have Bald Eagles, usually at least one pair, but so far they have shown no interest in masts. Hope that continues since I don’t think my solution would be any match for them. Hope the noodle works for you.
About 10 days before I was due to close on the sale of my PDQ, I looked across the marina lawn and privileged to watch an eagle destroy my wind rotor. Fortunately, the part was cheap and easy to install aloft, so I got right to it. I was scared it would screw up the sale.
There is a derelict sailboat in the next slip. Maybe I should install some attractive cat toys on the mast, so that they all go there;).
Brian Russell
October 28, 2025 3:13 pm
I have had excellent service from the Maretron WSO100 ultrasonic wind instrument, which lasted 8 years. I replaced it this summer with the new WSO200 (in Greenland, at the weather station wharf at PCS!). It has new delicate moving parts or extensions. I ran some thin stainless tie wire from its 200mm tall mounting post to locations fore and aft on the masthead. I’ve never seen a bird up there. The only caveat about installed the MAretron is that it needs an N2K cable.
I have no idea, but what an interesting idea! That said, contrary to the advertising I have often seen a bunch of seagull nests quite close together, perhaps 2 meters or so, if the aging memory serves.
Stein Varjord
October 29, 2025 9:37 am
Hi John,
I think your solution is good. It gives the same “message to the birds” as a solution I have found to work flawlessly:
Some years ago I bought a boat with the mast lying on supports above the boat. I left the boat a few weeks alone on a mooring in southern Norway. The local seagulls quickly made the horizontal mast their preferred hangout. At any given time, more than 20 would sit on it. Hundreds used it.
When I started to make the boat ready for use, it was disgusting, of course. I tried scaring them away by staying on the boat, rubber snakes, owls, long thin rotors and buzzers. They all worked, but at best for a day or two. The birds are smart enough to figure out that it’s not a problem for them.
The method that worked immediately and permanently was fishing line. I put a stick at each end of the mast and stretched a fishing line between them, about head height for the birds. This doesn’t hurt them at all, but they hate it when things touch their wings. It makes them feel unsafe. I did the same along all other edges on the boat. They prefer edges.
I was finished rigging this in the afternoon. That afternoon and evening, at least 50 of them tried to land, bumping into the fishing line and aborting. Trying another place, and aborting. Second day, not a single attempt. They had declared my boat an unsafe place. This lasted until I moved the boat away 5 months later. I’ve used it on later boats too and it has never failed.
The point is to make it unpleasant to sit there. Make it seem unsafe, unpredictable. They can certainly see the fishing line, but not well and not from a distance, so they sometimes get a surprising scare, which they will always avoid. Bird psychology. 🙂
I always put fishing line between the shrouds a bit above the spreaders, above the boom, along the edges of the salon roof and if needed, above the railings etc. Usually it’s enough to ruin the most tempting locations. They will declare the whole boat as unsafe, and communicate it to the others in their group. Any uninformed newbie up for a try will pick the most tempting spot, discover why it should stay away, and give the others a reminder about the “danger” on that boat.
I think the antenna method described in this article might be the best way to achieve this effect at the mast top, but I’ve used an antenna and the windex to put up fishing line there too. It doesn’t need to block all access, as long as it gives the birds the creeps.
Good idea and the bird psychology makes sense. That said, we did try it on our wharf at one point without much luck, that said, I think maybe we had it the wrong height.
David Eberhard
October 29, 2025 1:52 pm
In the northern half of Mexico on the Pacific Ocean side we have cormorants, osprey, blue and brown footed boobies, and worst of all are the Frigate birds. We had what you show without any relief.thankfully the Boobies are not much of an issue. The usually perch on the railings facing inboard. Thus their poop goes straight overboard. One landing from a Frigate can total out you wind instructions. Out of frustration I went medieval on the bird deterrents.
The wand is covered with spikes made from #10-24 screws ground to sharp points. I was going to post some photos, but don’t know how. End of problems.
Sounds like a good solution. Sorry, at the moment, you can post a photo on a Tip, only a full length article. I’m looking at solutions.
Bill Harney
November 1, 2025 10:32 am
After trying spikes, zip ties, owls, snakes with limited success I tried Bird Scare tape, a highly flashy, reflective tape from Amazon $5/roll’ I tied several pieces to a line run from topping lift to mast above the boom, also used on lifelines, pulpit. anywhere birds land, the birds don’t like the flashing. It’s worked well all season except for the dive bombers!
My Marina neighbors used something like this over the summer. I think the stuff they used, shiny silver tape, is plastic. By the end of the summer, most of the plastic tape was gone, blown off. More plastic into the water.
I was having a similar problem with purple Martins in my marina. Dozens of them would perch on several boats mast tops and shrouds. Their “poop” is very unsightly. I had a pool noodle that came with the boat and I hoisted up the main halyard (don’t forget the retrieval line). It worked like a treat! Simple and cheep!
-Bill
Hi Bill,
Amazing, I wonder why that keeps them off?
It sort of waves around in the breeze and seems to discourage them. I tried it on a lark and being frustrated cleaning poop off the deck 🙂 Maybe there were other easier targets as well.
Thanks for this John – I will be copying this install. I currently have no wind indicator for exactly this reason- I’m on my 5th one now – the bloody ospreys are relentless!
Hi Ben,
Glad it was useful and hopefully it works as well for you.
Hi John. Yes, an old VHF antenna wire sticking out at about 45 degrees over the radar scanner has kept seagulls it off for several years. But this year, for the first time, a gull perched on our bow pulpit rail and covered the roller furling drum in guano!
Cormorants are the worst of all. We went through a period where they were perching on the spreaders and covering the decks with the most disgusting mess of half-digested fish remains. Running the halyards from the masthead to the rail so they bisected the spreaders seemed to deter the cormorants and, although very plentiful around here, they have not fouled our nest for a couple of years.
Cormorants are strange beasts with foul habits. I was told that the aboriginal peoples called them “sea snakes”. Around here they have a penchant for invading small offshore islands in large numbers, roosting in the scraggly spruce trees, covering everything with guano that eventually kills all the vegetation leaving nothing but bare skeletons behind.
John Milton in Paradise Lost tells how Satan, when he decided to investigate what was going on in Eden in preparation for disrupting Paradise, disguised himself as a cormorant and flew in to reconnoiter the place. Milton was not much of a humorist, but I laughed out loud at that.
Wilson
Hi Wilson,
Yes, the cormorants are truly horrible. I had problems with them roosting on the spreaders on the M&R 56 and the solution was the same.
Around here we get birds building nests in booms. Obviously you can’t do much once they’ve nested in there without harming them or the chicks. Chunks of packing foam wedged in the open ends of any uncapped spars seems to be the best deterrent.
Again the incredible neatness of your epoxy work amazes us.
Hi Bryan,
Me too!
We use one of the Owl statues. The key seems to keep moving it around so the Osprey don’t get comfortable with its inert behavior. We added a pvc pipe out the bottom (secured with expanding foam). This allows it to be hoisted like a pigstick on the pennant halyard or to be placed in a rod holder. Every time I check on the boat I change it’s location. We are on a dock so I also pvc rod holders on pilings.
Hi Carl,
Thanks, I always wondered how effective those owls were.
I have a pigstick with a burgee flying on top of the mast. The pigstick has a full set of zip ties for 360 degrees around the stalk at different heights. They can’t land anywhere on top of the mast. I also have zip ties on all the spreaders sticking up so there is no place for them to land. My neighbor put a wire 2” above and parallel to his spreaders from the mast to the stays.
Hi Charles,
Good hack, thanks.
I mounted an anti-lightning static dissipator on my Sabre 38 to make the masthead less inviting to Chesapeake-based osprey. It has worked well. (I have the short version of the Raymarine windvane transducer arm so not too much room for a perch off the masthead.) And I have not had a lightning strike either, though I know that’s the subject of a different thread.
Hi Seth,
Thanks for the tip, always nice when we get an unexpected benefit from a piece of gear.
I installed a row of “spikes” along the boom by twisting on seizing wire. That was after my second repair from Osprey induced damage. The standard spike on the Windex and my VHF antenna seem to keep them from perching on the crane.
~Ed
Here in Michigan, it is the cormorants that are the offending avian agents. I took a 1 foot piece of clear plastic hose, split it lengthwise and pushed multiple small nails through it and zip-tied it to the horizontal arm of the wind transducer. This has effectively deterred the birds for years.
Hi Steven,
Sounds like a good variation and probably easier than mine.
Tied fishing line sbout 4 in up the ariel to the base of windvane arm
We also have a problem with seagulls building nests on deck
My boat neighbor saw them starting to build one on my boat so shooed them away ,about 6 seagulls then dive bombed him on his boat for days
Hi Bill,
We are lucky not to have that problem. We see plenty of gulls but they seem to stay on the wharf…so far!
I installed maretron’s ultrasonic wind instrument (WSO200) this spring. So far so good.
Time will tell if it’s robust to birds and the elements
Hi Mathieu,
I will be interested to hear how you fair, particularly on accuracy for using an autopilot in sailing mode.
Autopilot isn’t quite functional yet. It’s my first digital wind instrument and i do worry about the variability of the input. I think I’ll have to add a bit of smoothing on the data. I’ll update in the spring
Hi Mathieu,
Are you using Core for the heading and wind inputs to the autopilot? I have not tried that yet, but will. Be great to hear how you get on.
Aaah, We’ve had to deal with all the prior mentioned bird issues for many years at our YC. If leaving the boat on a mooring for anytime more than a few days in August we strangle the deck with hanging shiny tape to keep the terns from crapping everywhere. Living and staying aboard is the best prevention.
Our solution for mast-head ospreys for the last 5 years is also an ultrasonic instrument. Too small and slippery to land on. (Garmin/airmar. I found the Maretron to be less reliable). We’ve logged several thousand ocean miles using all the autopilot modes including wind vane. Working very well. Only caveat is making sure the sensors stay clean. I need to climb up and clean at least every six months with mild dish soap and water. Otherwise we get irrational wind speeds, especially when rainy or foggy.
Hi Chris,
Thanks for the fill on ultrasonic use for feeding autopilots. Great to hear it works.
Osprey are really cool birds of prey when watching them fish in the wild. Two years ago, I decided to sleep onboard with the hatches open (I sleep in the main cabin area on my last boat, 32′ Downeast) When I awoke, I had blood and other unknown objects on my chest! I thought I coughed up a lung during my sleep. When I looked up and out of the hatch, I found an osprey siting on the spreader (this boat has wood spreaders and they love to sit on them) tearing apart a bunker (menhaden) and dropping parts through the hatch.
Cleaning up the bunker parts and blood on the deck took hours! Much harder than seagull waste. I now have aluminum spreader and they avoid my boat.
Hi Dan,
Only one word covers that…Yuck!
Been thinking about your fix . A TIG stainless welding rod Could also be used
Hi Bill,
I thought about that but I don’t think it would be stiff and springy enough, but I could be wrong.
Bald eagles are a problem here. I had a VHF antenna, like the deterrent in the lead; they bent it over double. They ate two Windexes within two weeks, not just raining the plastic bits on deck, but wrapping the indicator wands like a pretzel. Far more destructive than mere ospreys, which I have lived with for 40 years.
I’m using ribbons on the shrouds (on a tri they are far from the sails and read true) until they go away.
The cormorants had moved in when I was at the boat yesterday. For some reason minnows were schooling around my end of the marina. Messy, but at least they don’t break anything.
I think I’ll try the noodle. Something like a spinnaker halyard and hoist it semi loose in the fore triangle? The line goes through the noodle, or some other way? Seems like it would chafe where the line moves in the head block? I have two spin halyards; I suppose I could reeve a cheap line in one of them.
(I Googled this–It says orange noodles attract Baltimore orioles, which are common around the water here. Maybe chartreuse.)
Hi Drew,
We have Bald Eagles, usually at least one pair, but so far they have shown no interest in masts. Hope that continues since I don’t think my solution would be any match for them. Hope the noodle works for you.
About 10 days before I was due to close on the sale of my PDQ, I looked across the marina lawn and privileged to watch an eagle destroy my wind rotor. Fortunately, the part was cheap and easy to install aloft, so I got right to it. I was scared it would screw up the sale.
There is a derelict sailboat in the next slip. Maybe I should install some attractive cat toys on the mast, so that they all go there;).
I have had excellent service from the Maretron WSO100 ultrasonic wind instrument, which lasted 8 years. I replaced it this summer with the new WSO200 (in Greenland, at the weather station wharf at PCS!). It has new delicate moving parts or extensions. I ran some thin stainless tie wire from its 200mm tall mounting post to locations fore and aft on the masthead. I’ve never seen a bird up there. The only caveat about installed the MAretron is that it needs an N2K cable.
Edit: “No”, not “new” delicate parts…
Has anyone had experience with these fake seagull nests? The blurb is convincing but what advertising isn’t.
Hi Bryan,
I have no idea, but what an interesting idea! That said, contrary to the advertising I have often seen a bunch of seagull nests quite close together, perhaps 2 meters or so, if the aging memory serves.
Hi John,
I think your solution is good. It gives the same “message to the birds” as a solution I have found to work flawlessly:
Some years ago I bought a boat with the mast lying on supports above the boat. I left the boat a few weeks alone on a mooring in southern Norway. The local seagulls quickly made the horizontal mast their preferred hangout. At any given time, more than 20 would sit on it. Hundreds used it.
When I started to make the boat ready for use, it was disgusting, of course. I tried scaring them away by staying on the boat, rubber snakes, owls, long thin rotors and buzzers. They all worked, but at best for a day or two. The birds are smart enough to figure out that it’s not a problem for them.
The method that worked immediately and permanently was fishing line. I put a stick at each end of the mast and stretched a fishing line between them, about head height for the birds. This doesn’t hurt them at all, but they hate it when things touch their wings. It makes them feel unsafe. I did the same along all other edges on the boat. They prefer edges.
I was finished rigging this in the afternoon. That afternoon and evening, at least 50 of them tried to land, bumping into the fishing line and aborting. Trying another place, and aborting. Second day, not a single attempt. They had declared my boat an unsafe place. This lasted until I moved the boat away 5 months later. I’ve used it on later boats too and it has never failed.
The point is to make it unpleasant to sit there. Make it seem unsafe, unpredictable. They can certainly see the fishing line, but not well and not from a distance, so they sometimes get a surprising scare, which they will always avoid. Bird psychology. 🙂
I always put fishing line between the shrouds a bit above the spreaders, above the boom, along the edges of the salon roof and if needed, above the railings etc. Usually it’s enough to ruin the most tempting locations. They will declare the whole boat as unsafe, and communicate it to the others in their group. Any uninformed newbie up for a try will pick the most tempting spot, discover why it should stay away, and give the others a reminder about the “danger” on that boat.
I think the antenna method described in this article might be the best way to achieve this effect at the mast top, but I’ve used an antenna and the windex to put up fishing line there too. It doesn’t need to block all access, as long as it gives the birds the creeps.
Hi Stein,
In the northern half of Mexico on the Pacific Ocean side we have cormorants, osprey, blue and brown footed boobies, and worst of all are the Frigate birds. We had what you show without any relief.thankfully the Boobies are not much of an issue. The usually perch on the railings facing inboard. Thus their poop goes straight overboard. One landing from a Frigate can total out you wind instructions. Out of frustration I went medieval on the bird deterrents.
The wand is covered with spikes made from #10-24 screws ground to sharp points. I was going to post some photos, but don’t know how. End of problems.
Hi David,
Sounds like a good solution. Sorry, at the moment, you can post a photo on a Tip, only a full length article. I’m looking at solutions.
After trying spikes, zip ties, owls, snakes with limited success I tried Bird Scare tape, a highly flashy, reflective tape from Amazon $5/roll’ I tied several pieces to a line run from topping lift to mast above the boom, also used on lifelines, pulpit. anywhere birds land, the birds don’t like the flashing. It’s worked well all season except for the dive bombers!
Hi Bill,
I always wondered about that stuff, so good to know that it works. Is it a big PITA to remove every time you go sailing?
My Marina neighbors used something like this over the summer. I think the stuff they used, shiny silver tape, is plastic. By the end of the summer, most of the plastic tape was gone, blown off. More plastic into the water.
Hi Terence,
That’s a very good point, that I had not thought of until you pointed it out, with many of these deterrents.