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Cities Use Spikes to Keep Birds Away. Birds Are Using Them in Nests--Researchers across Europe have found bizarre nests bristling with the sharp metal stakes cities use to repel birds
Scientific American ^ | July 18, 2023 | Meghan Bartels

Posted on 07/19/2023 7:02:28 AM PDT by SJackson


Large magpie's nest made of anti-bird spikes in Antwerp, Belgium. Credit: Auke-Florian Hiemstra/Naturalis

Naturalist Auke-Florian Hiemstra has seen a lot of bird nests, but none were quite like the one he spotted in a photograph from a patient in a Belgian hospital. This nest, high in a sugar maple in the hospital’s courtyard, was massive—and looked like metal.

“It just was this very big ball of metallic, nasty bird spikes,” Hiemstra says. On closer inspection, he realized a Eurasian Magpie (Pica pica) had built the two-foot-wide nest with materials that included some 1,500 spikes of the type cities often use to fend off feathered loiterers. Hiemstra ventured out onto the hospital’s roof only to find that the roof’s edge facing the courtyard was lined by a bare strip of glue, just like the kind often used to attach these spikes. And, perhaps strangest of all, the bird seemed to have arranged the spikes to form a defensive roof over the nest, much like the kind magpies often build out of thorny branches that they travel long distances to collect.

“It sounds like a joke,” says Hiemstra, a Ph.D. candidate in evolutionary ecology at Naturalis Biodiversity Center in the Netherlands. “I think it’s so funny that now they’ve started to use these anti-bird spikes in the same way that we intended them to be used.”

Hiemstra is a co-author of a new study published online July 11 in Deinsea, in which the researchers describe the Belgian nest and several similar spiky structures found across Europe: two magpie nests from Scotland and the Netherlands, and one Carrion Crow (Corvus corone) nest, also from the Netherlands. The scientists also mention a spike-embellished Carrion Crow nest reported in a 2009 paper and several reports from social media of birds interacting with rooftop anti-bird spikes—and even building nests directly over them.


Anti-bird spikes used in bird nests. Credit: Auke-Florian Hiemstra/Naturalis

Interestingly, the crows whose nests the researchers studied seemed to use the spikes not as defenses but as structural support, with the sharp ends pointed harmlessly inward. Crows and most magpies belong to a group scientists call corvids, which are known for being particularly clever.

“Corvids, as a family, are among the most intelligent of all animals—certainly of birds, but really across all organisms as we understand them,” says Kaeli Swift, an avian ecologist at the University of Washington who specializes in corvids. Swift wasn’t involved in the new research, but she says she isn’t surprised to see crows and magpies experimenting with unconventional nesting techniques.

Birds around the world use human materials in their nests in various ways, says Juan Diego Ibáñez Álamo, an urban ecologist at the University of Granada in Spain, who wasn’t involved in the new research. The use of anti-bird spikes is just an unusually ironic example of the behavior, Hiemstra says.

In a review published earlier this month, Ibáñez Álamo and his colleagues found that while the most common human material found in birds’ nests is plastic, these structures also incorporate things such as glass, cloth and even cigarette butts. And anthropogenic materials are found even in nests in areas people might consider pristine. “It’s not really related to more polluted areas,” Ibáñez Álamo says. “It’s not something that is restricted to cities. It’s everywhere.”

Because the nests featured in the paper are scattered across Europe, Hiemstra thinks many birds are independently exploring the reuse of anti-bird spikes—and he says he hopes that with the phenomenon now documented, curious observers will report other examples of nests that incorporate these spikes to help scientists better understand the behavior.

Hiemstra would also like to determine whether the unconventional nest material is helping or hurting these birds. Swift imagines experiments testing whether magpie predators are able to evade the seemingly defensive spikes, as well as observational studies comparing the nesting success rates of spike users with more traditional builders of the same species, that could be done to find out.

“We don’t know what happened in the nests—if there was successful breeding, if there was breeding at all,” says Zuzanna Jagiełło, a biologist at the University of Warsaw in Poland who worked with Ibáñez Álamo on the review of birds’ use of anthropogenic materials but wasn’t involved in the recent spike research.

For now Hiemstra says he’s taking hope from what he sees as an example of nature fighting back. “Using the material meant to scare birds off, using that to actually make more birds—I think it’s the perfect revenge,” he says.


TOPICS: Outdoors
KEYWORDS: birds; nests

1 posted on 07/19/2023 7:02:28 AM PDT by SJackson
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To: Iowa Granny; Ladysmith; Diana in Wisconsin; JLO; sergeantdave; damncat; phantomworker; joesnuffy; ..
Outdoors/Rural/wildlife/hunting/hiking/backpacking/National Parks/animals list please FR mail me to be on or off . And ping me is you see articles of interest.
2 posted on 07/19/2023 7:03:04 AM PDT by SJackson (he who controls the schools, controls the world, 1870s France)
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To: SJackson

3 posted on 07/19/2023 7:05:05 AM PDT by Magnum44 (...against all enemies, foreign and domestic... )
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To: SJackson

I Corinthians 3:19-20: For the wisdom of this world is folly with God. For it is written, “He catches the wise in their craftiness,” 20 and again, “The Lord knows the thoughts of the wise, that they are futile.”


4 posted on 07/19/2023 7:24:52 AM PDT by alancarp (George Orwell was an optimist.)
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To: SJackson

Avian ingenuity triumphs!


5 posted on 07/19/2023 7:32:58 AM PDT by Southside_Chicago_Republican (The more I learn about people, the more I like my dog. )
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To: SJackson

Magpies are smart birds..................

6 posted on 07/19/2023 7:49:37 AM PDT by Red Badger (Homeless veterans camp in the streets while illegal aliens are put up in hotels.....................)
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To: SJackson

“Nature finds a way.”


7 posted on 07/19/2023 7:55:15 AM PDT by bravo whiskey (Annie Savoy : The world is made for people who aren't cursed with self awareness. )
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To: SJackson

Bird 2x4’s.


8 posted on 07/19/2023 8:58:57 AM PDT by griffin (When you have to shoot, SHOOT; don't talk. -Tuco)
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To: SJackson

I put spike strips in an area Robins tried to nest on my patio. I gave up tearing nests down when she built one right in the spike strips. She hatched 3 nests that season and crapped all over my patio. Just one female comes each year and nests there. We think it is the same one as she is aging, but really have no idea. Probably just fond of thinking it might be the same monogamous pair.


9 posted on 07/19/2023 9:06:04 AM PDT by IamConservative (I was nervous like the third chimp in line for the Ark after the rain started.)
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To: SJackson

Probably somewhat effective against squirrels. Birds have been around in one form or another (dino”saurs”, for example) for millions of years. The ultimate survivalists.


10 posted on 07/19/2023 9:12:42 AM PDT by katana
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To: SJackson

Are the spikes so poorly attached that they fall off their mounts and the birds take them as they fall, or do the birds use special spike removal tools?


11 posted on 07/19/2023 9:36:23 AM PDT by fso301
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To: fso301

I looked up pictures of this, and it seems that one kind the birds are using is very thin long nail-shaped spikes pushed through a strip of sticky paper shaped like a series of diamonds. The nests were formed with the sticky paper diamonds and spikes, so it seems like the birds figured out how to lift the entire thing up off the glue-y surface.

Truly amazing!


12 posted on 07/19/2023 10:01:38 AM PDT by Chicory
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To: SJackson

Predators will find it harder to attack those nests.


13 posted on 07/19/2023 12:20:42 PM PDT by gitmo (If your theology doesn’t become your biography, what good is it?)
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To: SJackson

This is really nothing new. Many facility managers have known for decades that the spikes aren’t effective except to anchor the pigeon nests on the building.

On parapets and ledges the tensioned, thin stainless steel, parallel wire systems, like those by BirdMaster, work best. They’re not as visible as the spike strips either. The wires make it difficult for a bird to land and if they try to build a nest in them the rain or wind usually clears it out.

Netting is often good to protect column capitals and other architectural features, especially on ornate historic buildings.

The sprays and paints don’t work except to cause an expensive mess or stain to clean up.


14 posted on 07/19/2023 1:35:40 PM PDT by chickenlips (Neuter your politicians)
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To: Magnum44
lol... thought this immediately!! and they also found the new construction materials were in place upon returning from migration!!

100 year warranty on nesting spikes!!

15 posted on 07/19/2023 1:39:13 PM PDT by sit-rep
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To: alancarp

Amen. PRAISE JESUS!!!


16 posted on 07/20/2023 9:58:04 AM PDT by Bellflower (Who dares believe Jesus? He says absolutely amazing things, which few dare consider.)
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To: SJackson

Whose the bird brains now? LOL


17 posted on 07/20/2023 9:59:10 AM PDT by Bellflower (Who dares believe Jesus? He says absolutely amazing things, which few dare consider.)
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