While in the car tonight, my 6-year-old daughter was pondering various things like why the moon appears full sometimes. Then my wife asked if scarecrows actually worked. We are talking about the stereotypical scarecrow on a pole in a corn (or whatever) field. If they work, and I am assuming they are supposed to “scare” “crows,” how do they work? I mean, when you see a classic depiction of a scarecrow, a lot of times there is a crow on the shoulder. So, what’s the staight dope? And should I submit this to Mythbusters?
They usually work for a while but crows are relatively intelligent and curious birds. They’re initially cautious about what appears to be a threat but when they see that the guy standing in the field isn’t moving they will start flying closer and eventually realize he’s harmless. For scarecrows to be effective, they have to be moved to a new postion regularly so they don’t become too familiar.
It depends upomn the kind of scarecrow you mean. I looked into this for my book, and found a huge amount of anecdotal evidence, along with a handful of actual published studies by John Conover (now of Utah State University) and Ronald J. Prokopy of University of Massachusetts at Amherst. But they weren’t on your traditional scarecrows – they were on predator bird-shaped scarecrows and on the “Terror-Eyes” or “Scare Eyes” ballooons that have huge owl-like eyes on them. These were effective.
Prokopy’s results were impressive. Before any scarecrows were used in the fruit orchard he examined, bird damage affected 12.2% of the fruit. He put a single Scare Eyes balloon in the center. Trees were four yards apart in each row, with rows six yards apart. At the end of the season, damage to trees within six yards of the balloon was 1.5 percent, while twelve yards away it was at 11.7%. The next two years he placed balloons every 12 yards throughout the orchard. He had 0.4% bird damage that year, and 0.9% the next.
The balloons are moving “scarecrows”, and their lenticular eyes give the illusion of moving, too.
The same basic idea lies behind those plastic and ceramic owls (The US Navy reported success with ceramic owls, but published no numerical data to back it up). I have suggested that the classical Greeks and Romans used the same devices – “Oscilla” and what have been (incorrectly, I believe) termed “drinking bowl masks” strongly resemble these balloons, right down to the “living” eyes, and with the addition of chimes to help scare birds away.
As for “traditional” man-shaped scarecrows, who knows? I have no studies on those. Many of the scarecrow devices used throughout the years and across the world have been static, but the most widely-used ones have oversized, staring eyes. If you made your scarecrow like that,. I bet it’d work. But one with small eyes, my suggestion would be don’t even both.
references:
Ronald J. Prokopy, **Fruit Notes 56 ** (2)p. 16 (Spring 1991)
Michael R. Conover J. Wildlife Management 49 (3) 643-5 (1985)
Michael J. Conover “Response of Birds to Raptor Models” in proc. of the 8th Bird Control Seminar Bowling Green State University, Bowling Green, Ohio (1979)
Wow, thanks for the responses. I really would like to see someone study this with traditional scarecrows though. Maybe I will suggest it to Mythbusters, heck, they did bull in a china shop.
Note that a traditional scarecrow is supposed to be dressed in old, used clothes – unwashed! The human smell of those clothes is an element in discouraging the birds.
In the Philippines they use white plastic bags tied to sticks, a few feet off the ground. I’d like to see that compared to other methods of scaring birds.
A farm near me uses 4 foot sticks with aluminum pie pans tied to them by a short piece of string. This lets them move in the breeze, make a little noise and shine in the sun. It seems to discourage the birds and the deer very well.
I have visually seen birds perched on a standard scarecrow. I wasn’t aware they worked at all.
I’ve never seen studies on it. Squirrels are smarter than birds, so maybe not.
I’ve long suspected that the “eye spots” on Greek “Eye Cups” and on old European pottery serevaed a parcitical purpose of deterring mice and other pests from getting into the jars. Even if it didn’t work perfectly on squirrels, every bit helps.
I’ve heard of people using CDs (like those omnipresent AOL discs) strung from strings and ghanging in gardens to keep pests away. Something similar was used in 19th century america, where people would put up swinging items in trees to deter pests. Motion, as I say above, is important. Coupling it with the statrtling Staring Eyes improves its effectiveness.
I’d always asked myself this question until I saw it work. Instead of crows, though, they were sea-birds (lots of different types). Instead of fields, there were lots of parked fishing boats beyond the roped-in, swimming area. The scarecrows weren’t necessarily “Wizard of Oz”-looking things, but a little more field-expedient, but with clothes and baseball hats. Of all of the boats (about 15), the only ones that didn’t have perching birds (and consequent bird crap) were the two with the scarecrows. Not being a farm boy, I thought it was pretty frickin’ amazing.
Cite please, I was not aware of this. I thought bird intelligence varied and that crows and the Corvus genus were near the high end of bird intelligence.
Crows and Ravens are particularly known for being smart. I did not realize squirrels were considered smart. They just might not process the data of the fake glaring predator eye the same way.
For boats, I’ve seen people use ropes with weights on the end attached to the highest point on the cabin. As the boat rotates in the wind, or the winf blows the weight attached to the rope, that rope moves around the cabin top and the gulls evidently find it annoying to have to keep shiftimng their perch. at any rate, I see neither their presenvce nor their droppings on boats so equipped.
It’s not reallty a “scarecrow” of any sort, but it is an anti-bird device.
By the way, Prokopy claimed the balloons were most effective against crows, starlings, bluejays, and possibly blackbirds, but were less effective against robins and orioles. The US Navy’s ceramic owls were succesful (they claimed) against gulls. One place I worked at swore that they bird scarecrow was superb against pigeons.
Haven;'t got ione – I was thinking of squirrrels vs. pigeons or starlings. I don’t know how csmart squirrels score on a general scale, but I’ve been impressed with films I’ve seen of squirrels working their way through a series of puzzles and traps to get to food. They routinely outwit anti-sdquirrel devices on bird feeders.
My sister had a pet squirrel, they are fairly bright as animals go, but by the accounts and one study I read, I would believe crows to outscore them. Some crows are actually tool users and most crows are problem solvers.
As much as we can scale animal intelligence, Crows score high. Pigeons, not so much.
I am far from an expert, I hope Colibri or maybe **brachyrhynchos ** finds their way into this thread now.
Yeah, but crows are really great learners, too - I read in National Geographic once that if you tie a piece of food to their perches with a really long string, they’ll learn how to pull the string up, step on it, pull it up, step on it, etc until they get to the meat at the end.
The film I saw was FAR more complex than that. To get to the food, the squirrel had to solve, in order, a series of something like eight problems, each of which brought it incrementally closer to its goal.
A similar show had birds solving problems to get to food as well. But the squirrel had easily the most complex maze of tests to get through.
I’ve seen pigeons roosting on top of those plastic owls. The first time I saw it, I thought, “Huh. Stupidity, also, is a force of nature.”
Along I-5 in California, a lot of the vinyards tie strips of silvered plastic ribbon to the vines. The blow in the breeze and flash. Looks kind of cool. I assume it’s to ward off birds, although I’ve never checked up on it.