I never see them but I see their mess

[Percy]

Im assuming crows are hanging out in my trusses after I go home. They must be eating good. Any suggestions on how to deal with this? Its getting costly...

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[YellowHammer]

I've never seen a crow in a building or in trusses, they like open roosts.  Maybe owls? Pigeons coming back in the evening to roost?

[doc henderson]

pigeons will do that.  building my shop in Hays, America I had open eves and some trusses for a while.  We had a pump-up pellet/ bb gun with a scope and could knock them down and not damage the building.  My brother came and shot pigeons for a while.  then we got out the 270 for target practice... and boom.  he got scoped and I had to put stitches above his eye.  He put his eye near the scope like he had been doing with the bb gun.

[Nebraska]

Kinda reminds me of pigeon variety.

[YellowHammer]

Give us more specifics in when you leave and show up again?  Do you see no unusual bird activity?  What species do you see nearby? Ain't nothing better for a wad of birds in a building than a BB gun "whack and stack em" party!  I'm in! 

[Ianab]

First suspect in these parts would be starlings. They tend to leave their roosts at first light and only return at dusk, and a certainly happy to take up residence in a shed. 

[Percy]

The only birds I see during the day are crows so that was my first guess. There is a few barnswallow nest in the trusses but they are tiny and couldn't crap like that. Plus they have been there since I built the building in 2013. The poop happened a few years ago but it was minor. I hung up some owls painted on tin I got from amazon but now they are laughing at the phones owls. 

Perhaps a game camera with night vision?? But then what do I do with that info??

My zoom boom is covered in crap and customers are laughing and commenting( perhaps they are commenting on your quality control)🤣🤣

[doc henderson]

The college in Hays (Fort Hays State University) had a bird trap.  it is a wire box with a trap door on a side with fingers like the drag back on a wood Mizer.  the birds see grain and walk in but cannot walk out.  I later used it to trap a bunch.  my office manager s dad worked at the college.  I think he made it.

[Ianab]

Have you tried going out at night with a powerful torch and seeing who you disturb? If it's pigeons you would at least hear them if you disturb their nap. 

Otherwise have you thought of getting a pet ferret?

[doc henderson]

Birds are creatures of habit.  We made the mistake when we had about 60 ducks and chickens of raising up hatchlings in my shop away from the other birds.  as they got bigger, they would roost in there.  Later in life, if we had a door open in the evening, they would sneak in and go to the roost.  If I did not realize till the next morning, there would be droppings to clean up and chickens to shoo out.

[twar]

These are commonly used here. You can buy them in lengths and cut and mount them as needed.

[Peter Drouin]

Easy, Take away the habatat. Get something cheap like thine plywood and put it up. Paint it white for more light under there. One time deal, you never have to think about it again.
Do a good job and don't leave any holes. Or you could waste a lot of time and kill everything, then more will come.  
Good luck. 

[SawyerTed]

Solar lights if you don't have power.  If you do add some bright lights.  Then hang shiny objects like pie pans, CDs or foil.   The light, motion and reflections will drive the birds away. 

[Raider Bill]

How about one of those propane mortars that goes boom every so often?

[Ron Wenrich]

I had pigeons in my barn for a number of years.  They would leave during the day an roost on the big electric tower down in my field.  They would come back about dusk and spend the night.

One day, a Coopers hawk figured he could get easy pickings in my barn.  He started to clean them out.  The pigeons left and never came back.  They found a new place to roost.  The only problem I have now are barn swallows, which are even messier, but seasonal. 

Maybe a decoy would work. 

[YellowHammer]

I'm with you, they need to "leave, and now."  Bird poop is nasty, corrosive to paint and metal, and disease carrying.  My cousin, a farmer in Kentucky, had half a lung removed from histoplasmosis, a disease caused by breathing bird poop, supposedly from birds roosting and nesting in his equipment sheds.  I once had an eye infection when some bird poop that I was cleaning got into my eye and I didn't flush it out correctly or fast enough.  I literally felt it blow into my eyes, I remember thinking "I need to flush my eyes out" and I tried, but not good enough.  Two eye surgeries and few month later, because it spread through my tear ducts from one eye to both eyes, which was a joy, I vowed that would never happen again.  Now I keep birds out of my buildings with "extreme prejudice".  Be careful cleaning their poop up, keep the dust down, best thing is to wet it and wipe it off (I use WD40 when it's on my metal equipment).  The way I look at it, birds have the whole world to nest and poop in, but not in my place.  I may not be able to keep spiders out, but anything big enough for me to see their poop, will be evicted.   

I once fired one of my wood suppliers because they stored their exotic wood in a warehouse and they would deliver it covered in bird poop, so I had to run the wood through my planer to clean it off, and did I mention about what happens when bird poop turns to dust an gets blown around?  Thats NOT GOOD.  I figured if he was too busy to keep birds from pooping on my wood, then he was too busy for my business.  Sound like you may be getting some of the same feedback from your customers?

I think you need to find out what species they are to really figure out how to control them or harass them out.  If they are pigeons, they are pretty easy, but in my experience, most times pigeons can be seen roosting on the rooftops or nearby before they fly in, or will give other clues to their presence.  If they are owls, then you have to call Fish and Game, at least here in Alabama, because they are protected.  I have birds that love to nest on top of my garage door openers, every spring.     

I used to have a barn cat that really kept them away, cats can easily climb on all the rafters, walk back and forth, but some are hunters and some are just Garfield's.  Do you like cats?

I've got plastic barn owls in my buildings and they may work, I can't tell.  My neighbor strings 3 foot lengths of yellow caution tape like long streamers from the rafters of his place, and that fluttering of plastic does a pretty good job,  He also keeps a pellet gun next to his shed and which also does a pretty good job.  In my buildings, there are little night sparrows and other little guys that come in at night and poop on my stuff, however, they usually start to build a nest.  I remove their nest a few times, they get the hint, and leave.  Some are not so smart, I once had a "yellow belly" (I don't know what it was) try to build a nest in my dust collector blow pipe every night when I turned it off.  Every morning I would turn it on and blow the bird its night's work of sticks and twigs out, and the determined little bird would literally fly against the airstream trying to get back into the blow pipe! After several days, it left. 

The birds are there because they can sleep, roost and possibly this spring, nest in peace, so that needs to change, somehow.  I leave my lights on in my barns and that helps keep them out for the most part, and makes them easier for me to see at night if they decide to stay.  Some songbirds are protected by law, so not suitable for "lead poisoning" but nothing solves the problem of non protected bird species faster than a Red Ryder.

[Raider Bill]

They string monofilament fishing line around rafters here to keep the sea gulls away.

[jpassardi]

Based on the volume of "white grease" I'd say not an owl or hawk. It's a flock of something.
Best long term solution would be to block off the bottom chord of the trusses but it is a big area - maybe a mesh sheet fastened to the bottom, not sure how pricey they are.

[Andries]

It looks like crow crap to me Percy, given your location.
Peter Drouin's solution sounds good to me but I'd go with something other than sheet goods.
How bout this:
https://www.amazon.ca/Netting-Protection-Barrier-Protect-Reusable/dp/B0CZ6JVMLD/ref=asc_df_B0CZ6JVMLD/?tag=googlemobshop-20&linkCode=df0&hvadid=706745932765&hvpos=&hvnetw=g&hvrand=1528730148344541691&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9001186&hvtargid=pla-2309434591669&psc=1&mcid=ba717fb3b6643cb9a399125a3c6f0088&gad_source=1
Like Peter said, it's a do it once kinda thing.
BTW - your lumber looks like crap lately Y'know? 😂😂😂😂

[jpassardi]

Yes, I was suggesting a mesh like that.

[Jeff]

I cured 3 bird problems this year, and I can talk about a 4th. All non-lethal, as usually the offenders are protected somehow
Once you know what you are dealing with and why they picked you, change it up.

We found great blue herons were camping on our pond, to keep them from moving in, I used wooden stakes from balsam poplar sprouts, cotton string and mardigras beads.  We have very little shallow water, and herons are wading birds, so no real place to land on the pond, they wade up to it. I staked the perimeter,  about every 20 feet, or less on curves, strung the twine on them by simply twiting around the sticks knee high to me. We then twisted a hunk of mardigras beads between the stakes. The birds wont walk into or through the string and cant land on the other side. It only took a day and night and they didnt come back.

I got to witness the amazing dive of a kingfisher into my pond, right in front of me. Awesomeness but big problem. Fix? I went to black pond dye. Makes the pond a mirror.

Three seasons ago we lost most of our wolfriver apples to maurauding swarms of bluejays pecking the tops out of the apples. The following season, once fruit was set, I put netting up. A month later, to my horror, I found at least a half dozen small birds caught in the net and dead at on time. I immediately took that down. This year we tied with twine about a dozen dvds from the limbs of each tree we wanted to protect. They twist and flash, and worked perfectly, and ruined my fall grouse harvest of picking them out of the apple trees while eating buds. They don't like em either.

When I first put my pole barn up, robins continually tryed to nest on top of my security light on the gable end. Id knock the nest down, and they would be back. I finally tried putting a rubber ducky up there. I witnessed the robin go up and kick its ass off the perch. Twice. I then got a small chunk of heavy duty velcro tape from Tammy and stuck him back up there. The robin came back, made a hovering attack and failed. 7 years later the duck is still up there.

Find what yer dealing with and make it not like you.

Unless its a crow...

[Jeff]

Have you tried going out at night with a powerful torch...

Otherwise have you thought of getting a pet ferret?

I'm glad to have had you as my friend all these years Ian, for the education in the nuansic (made that adj up) differences in our common language. I say this, because only for less than a moment did I think you meant for him to burn his barn down. Oh yea. Flashlight. 

[JD Guy]

@Percy @doc henderson 
If in fact the birds turn out to be pigeon then I would suggest if you have any bird hunters with dogs or bird dog trainers in your area they would most likely be more than happy to come and trap and remove them from your building. They will use them in their training regimen and more than likely shoot them for the dog to retrieve. Since they're not homing pigeons even if they are not killed they likely won't return to your building they'll find someone else to bother 

[Magicman]

Solar lights if you don't have power.  If you do add some bright lights.  Then hang shiny objects like pie pans, CDs or foil.   The light, motion and reflections will drive the birds away. 

I would use Ted's suggestion first, and I'm guessing that you won't need a second.

[beenthere]

Not sure whether a crow or pigeon, or some other big bird, but not characteristic of crow. Maybe a western Canada crow is different than midwest US crows. Whatever, should be evident from observing whatever bird flies out of the shed after roosting in the night. 
Frustrating for sure, gross absolutely. 

Shining a light up into the trusses during the night should also identify the guilty bird or birds. Keep your mouth closed when doing this.