JOHN THE OBSCURE ™

© 2010

Stuck in the Past: The Sick History of Trapping Birds with Glue

Reading “Orlando Furioso” last month, I came across an allusion to birdlime, an archaic glue used in capturing birds, and decided to see just what that was all about. Having since cursed in alarm as I accidentally plunged my fingers into a “super hold” mouse glue-trap, I can assure you that birdlime is no fun.

But I got off easy. In the five centuries between “Orlando” and today, untold hundreds of millions of birds were captured with birdlime, a method that can strip off skin and tear off legs, and always traps indiscriminately. Birdlime is widely illegal and largely forgotten today—the word is shifting to mean “bird droppings”—but still lurks behind the scenes of such localized horrors as boiled-songbird restaurants.¹ And birdlime is still with us in the form of modern products it inspired—flypaper, “Roach Motels” and rodent glue-traps (“with us” literally, in my sticky case).

Bird-catching for food, industry, the pet trade and mere sport was long popular enough to merit full-blown encyclopedia entries and how-to articles in popular magazines. Along with the usual snares and traps, as described in such sources, were an array of capture methods that would delight any Guantanamo torturer with their elaborately inhumane ingenuity. Want to catch some pheasants? Go under their perch tree at night and burn a heap of sulfur, “the suffocating effluvia of which makes them fall senseless.”² Already caught a live crow? Forget whatever boring normal method you used to do so, and catch more by pegging your crow spread-eagle (or spread-crow) to the ground, whereupon more crows will come to torment it, and clutch talons together in battle with your decoy bird, enabling you to grab up as many as you like.³

On this spectrum of bird-trapping, birdlime falls somewhere between the commonplace and the grotesque. Birdlime is the name for any number of plant-based glues that, spread thinly on a branch or similar item, ensnare the feet or feathers of a bird. A common “liming” method was to prepare twigs or sticks with the glue, then insert them in holes drilled into the trunk of a tree. Birds would come to perch; become stuck to the twigs; struggle and dislodge them; then topple to the ground for easy pick-up. Birds as large as hawks could be taken this way.

Birdlime took the place of string snares in normal traps baited with insects or even with an eye-catching piece of mirror. Limed strings were set up to catch birds like oversized cobwebs. A still common method is to lime a bit of wood at the end of a long pole, then sneak it close enough to a perching bird to give it a gluey tap.

One incredible 18^th century encyclopedia article, so popular that it was plagiarized for decades, recommended souping up your birdlimed twig trap by using a live bat or owl as a decoy.⁴ (It was apparently a safe assumption that you had such a creature from a former birdliming foray, thanks to the glue indiscriminating trapping virtually anything that might visit a tree. But there were always options in this wildlife-slaughtering era: “If a live owl or bat is not conveniently to be had, you may use a stuffed one, which will serve the purpose, and last twenty years.”) There was no explanation as to why a bat would be a good decoy, but the owl was based on the fact that smaller birds often will harry a predatory bird. I found a reference to at least one birder who kept a domesticated owl for this purpose.⁵

Legend has it that the ancient Greeks captured cranes by smearing the inside neck of a vase with birdlime and placing bait inside. A particularly cruel suggested modern version of this, intended for abusing crows, was to lime the inside of a paper cone baited with a bit of meat. As one author explained, “When the bird pokes his head in, his eyes are gummed up and blinded, and he flies straight up in the air, but soon falls down exhausted, and it may be dead with fright.”⁶ This practice supposedly was once carried out by an Italian landholder as a way to entertain his guests. True or not, the method was recounted, generally with amusement, in several 19^th century birding books. One described the cone jovially as a “fool’s cap.”⁷

Birdlime is a weapon that is always loaded and doesn’t care what it catches. That includes frogs and even monkeys.⁸ The latter have been caught in Japan with birdlime, reportedly because their efforts to remove the glue exhausts them. There are fanciful tales of tigers being caught via birdlimed leaves spread in their path, with the removal effort similarly exhausting them—an image so appealingly strange it appears repeatedly in popular and children’s literature from about 1840 to 1940.

But the most common alternative usage for birdlime was in pest control. Birdlime was the adhesive in the first form of flypaper and rodent-trapping glue boards, used at least 130 years ago and probably much earlier. One British journal article from a century ago recommends trapping rats by applying birdlime to straw near their holes: “The next morning, the straws will be found gathered up into little bundles, in the center of each of which is a rat.”⁹

There is no lime in birdlime—“lime” in this sense simply means “glue” (ultimately from Latin “limus,” meaning “mud”). While any small creature can stick to the glue, it’s probably called birdlime because of the social importance of bird-catching and because the original sources of the glue were from trees, right in bird habitat. In ancient Greece, birdlime was made from mistletoe berries. The most popular European sources in the 18^th and 19^th centuries were holly bark, linseed oil and a certain type of locust (Robinia viscosa, apparently so named for its gluey juice). In the Balkans, fig juice was one option. In southern Africa, birdlime came from cacti; in Pacific islands, from breadfruit; in Algeria, from a thistle-like plant; among the Native Americans of today’s Florida, the gumbo-limbo tree. (For the more bloodthirsty, I found a suggestion that birdlime could be made from the putrefied and boiled remains of “our more slimy and tenacious worms and caterpillars.”¹⁰)

Birdlime could be as enormously wasteful in its manufacture as it was in its application. Making it from holly bark involves killing the entire plant in the long run, and discarding 90 percent of the material to get the extracted glue.¹¹ Production typically involved repeated boiling, pounding and washing of the plant material, which was then cut with oil or other ingredients. The linseed oil version was toxic to birds, which had to be captured quickly lest they ingest some of the birdlime in their struggles.¹²

The similarity of birdlime to latex was often noted in the 19^th century as rubber became a valuable substance, and there was some discussion of attempting to vulcanize it. (While “birdlime” is an umbrella term for a glues from a variety of plants, both naturally gathered and artificially manufactured, it often was discussed as a singular, even unique, substance in early 19^th century chemical literature.¹³) Indeed, in some cases, such as breadfruit, the plant product used for birdlime is a latex.¹⁴ Birdlime vulcanization appears not to have panned out. But birdlime had a few industrial applications, including as a varnish for coating aeronautical balloons.¹⁵

Like all plant products, birdlime also has a history of medical uses back to ancient Greece, where it was used in plasters. In the early 1800s, it was considered a skin-softener and a swelling-reducer.¹⁶ In an 1845 edition of the journal “The Medical Times,” an author proposed that a plaster of mistletoe-based birdlime and yellow wax would relieve tic douloureux, a neuropathy that causes a stabbing pain in the face.¹⁷ “Absurd as these directions may appear,” they will work, the author assured readers, adding that while some patients complained of heat and blistering from this birdlime plaster, others experienced a “sensation of dreamy fluttering and delightful lolling of the senses.”

Birdlime was one of those things that was so common that few people bothered to write down what it actually looked like or how it was used. It was sold in tins by taxidermists and bird-dealers. It seems that the European version was typically greenish in color and always thick, stringy and intensely sticky. Its odor and flavor varied from none to strong depending on the plant source; the holly bark version had a sour flavor and an odor like linseed oil.¹⁸ Birdlime only stuck to dry surfaces, so it could be handled carefully with wet hands and tools. One application method was to pull up a string of the sticky glue with the point of a knife, cut it off with wet scissors, and then spread the stuff on the desired surface.¹⁹ There was something of an art to spreading it at just the right thickness—not too thick to dissuade birds, not so thin that it failed to trap them.

What about getting the glue off a captured bird? It was even more challenging to find any mention of that crucial step. The best reference I could find suggested using butter or kerosene, with the latter preferred.²⁰ An article on bird-trapping in India claimed that a rubbing with “dry ashes” sufficed to remove whatever was used as birdlime there.²¹

Even in its heyday, birdlime was controversial for its “usually attendant cruelty” and its ecological impact.²² An 1878 U.S. Forest Service report noted that a single experienced bird-trapper in 1850s France would catch 300 to 400 birds a day using birdlime. The scale of the slaughter, which killed off insectivorous birds beneficial to farmers, led one Frenchman to write an anti-birdliming screed called “Don’t kill your friends.”²³

With the rise of humane societies and hunting restrictions, birdlime was becoming an anachronism by the early 1900s. Today, it is illegal and largely forgotten in the Western world. John James Audubon, the 19^th century animal thrill-killer who nonetheless inspired part of the modern conservation movement, caught birds with birdlime; this week, a National Audubon Society spokesperson did not immediately recognize the word when I asked about it.²⁴

That’s not to say birdliming is dead—far from it, according to BirdLife International, a U.K.-based coalition of conservation groups. “[Birdliming] has blissfully died out in most of Europe, but there are some persistent pockets of poaching in the Mediterranean countries,” especially Malta, Cyprus and Italy, said Ariel Brunner, BirdLife International’s Belgium-based head of European Union policy, in an e-mail. Brunner has some family experience with this cultural shift, noting that “my father used to be seriously into birdliming as a kid in rural Friuli [a region of Italy].”²⁵

“[Birdliming] is still very common in Africa and the Middle East (and, I presume, Asia),” Brunner said. Indeed, the India branch of People for the Ethical Treatment of Animals reports that liming is still rampant there for the pet trade.²⁶

Cyprus presents a particularly gruesome case study of traditional culture—in this case, birdliming—clashing with E.U. internationalism. On that island nation, the birdliming is done to provide the main ingredient for ambelopoulia, a dish of pickled or boiled whole songbirds. Cyprus is a major stop for migratory songbirds, and capturing them is illegal, but the ban is widely ignored by trappers and restaurants, with more than 1.1 million birds killed in 2008 alone.²⁷ Nets—another illegally indiscriminate killing method—also are used in the songbird-catching, but the use of birdlime made from local fruits is widespread. This birdlime can be so strong that the birds’ legs must be amputated to remove them. Either way, the limed birds are typically killed on the spot, “usually with a toothpick to the throat.”²⁸

Memorably unappetizing as this is, it appears that time is on the anti-birdliming forces’ side, at least in the E.U. Brunner said that general enforcement is up and liming is down. Meanwhile, birdlime’s direct descendents—flypaper and rodent glue-traps—are everywhere, as common as birdlime once was and available in any hardware store. I figured a nightmarish glue that could ruin anyone’s day would be sold in a sealed-up package, which is why I got a nasty surprise by sliding a mouse glue-trap out of its box and grabbing it without looking.

The flypaper and glue-traps that I bought and examined use viscous adhesives that are unidentified beyond meaningless marketing terms like “space age glue,” but I doubt any of them are birdlime.²⁹ The flypaper had a faint but sharp scent of camphor or pine sap, so it may still include a plant product. The glue-traps, from my very hands-on examination as well as patent filings, appear to contain a silicone gel. Most of them are far easier to clean off than birdlime was. Flypaper glue comes off with soap and water. Various glue-trap packages recommend different removal substances for their adhesives (sometimes varying on the same product or in the English and Spanish versions of the same instructions): cooking oil, mineral oil, alcohol and/or paint thinner.³⁰ I avoided the irony of having my adhesive-coated fingers stuck to my keyboard while note-taking for this column thanks to two dousings of cooking oil. (The first was not enough to totally remove the glue.)

That’s convenient for a human who easily pulled his fingers out of the glue while improbably exclaiming, “Hell’s bells!” and retaining enough free digits to handle a jug of cooking oil. For a mouse, there’s no magic potion and a glue-trap is nothing but a brutal way to die designed by someone a bit unglued.

Glue-traps have been around forever, but started gaining popularity after the burst of legislation restricting pesticides in the 1970s, as the traps contain nothing but glue and perhaps a bait. Now more than ever, pest control companies market glue-traps as a greenwashing tactic. For example, Black Flag sells its “Roach Motels” and “Fly Motels” as “green” products and an example of how the company has been “selling environmentally friendly products decades before they became mainstream.”³¹ Meanwhile, this is the same company that will still sell you pesticide in an enormous, spray-all-you-want jug.

Pesticide might be preferred by rodents if they had their choice of execution methods. A 1980s study of glue-traps found that entrapped mice sometimes struggled so violently that they broke their legs or tore out big patches of fur. While some mice went face-first into the glue and quickly suffocated, it took most of them a minimum of three hours to die. It is death by stress, dehydration or starvation. ³²

It’s a sticky business, deciding which animals we love and which animals we hate. In the last 100 years, we have decided that putting an indiscriminate glue-trap out in the world is a really bad idea. Today, we believe that putting an indiscriminate glue-trap inside a human habitation is still OK. Birdlime is still with us, but we have changed our minds about the bird part. All of the glue-traps now bear a similar warning:

“CAUTION: Do not place traps where birds or non-target animals may come in contact with the adhesive.”

¹ An example of the shift in the meaning of “birdlime” is the product Bird Lime Neutralizer, intended for removing bird droppings from car paint. (See www.valetshop.co.uk/manufacturers/supagard/aftercare/bird-lime-neutralizer.htm.) When I first contacted the National Audubon Society about birdlime, their spokesperson was unfamiliar with the term and did a Google search that found the bird dropping meaning. It is unclear exactly why the word “birdlime” was retained and is beginning to take on this new meaning. As I explain later in the column, the “lime” in birdlime literally means “glue.” A common meaning of “lime” today is the white powder produced by heating limestone, which is called “lime” because of its use in mortar. It is possible that this new meaning of “birdlime” is based on folk etymology that is referring to the lime-like appearance of the white uric acid component of bird droppings looks like lime. An interesting example that could bolster this interpretation is an article on the web site of People for the Ethical Treatment of Animals India, which claims that a form of birdlime consists of tree sap and “slaked lime.” Slaked lime has never been an ingredient of birdlime, so this is either a fictional piece of folk etymology, or, more intriguingly, birdlime makers are now adding lime to match the folk etymology. (See article “India’s Bird Trade” at www.petaindia.com/campaigns/entertainment-birds.asp.)

² “Bird-catching” in “Third American Edition of Nicholson’s British Encyclopedia, or Dictionary of Arts & Sciences,” Vol. II, William Nicholson, ed. (1819).

³ “Bird-Catching in India” by E.W. Harper in “The Avicultural Magazine,” June 1903, Vol. I, No. 8, p. 262.

⁴ “Bird Catching” in “The Laboratory; Or, School of the Arts” (6^th ed.), Vol. II, G. Smith, ed. (1799).

⁵ “A History of Fowling: Being an Account of the Many Curious Devices by which Wild Birds Are or Have Been Captured in Different Parts of the World” by H.A. Macpherson (1897).

⁶ “The Art of Travel; or, Shifts and Contrivances Available in Wild Countries” by Francis Galton (1855).

⁷ “Camp Life in the Woods and the Tricks of Trapping and Trap-Making” by W. Hamilton Gibson.

⁸ Frogs, according to Ariel Brunner, head of EU policy, BirdLife International, Brussels, Belgium, in Aug. 13, 2010 e-mail forwarded via National Audubon Society spokesperson Delta Willis. Monkeys, according to “Japanese Bird-Lime” in “Chambers’s Journal of Popular Literature, Science, and Art,” Aug. 17, 1878, Vol. 55, No. 764, p. 528.

⁹ “Birdlime for Catching Rats and Mice” in “Medical Record: A Weekly Journal of Medicine and Surgery,” Dec. 7, 1901, Vol. 60, p. 892.

We know definitively of the use of birdlime in making flypaper thanks to a 1906 lawsuit between chemists, where one alleged receiving bad birdlime from the other for flypaper-making. (Source: “The Pharmaceutical Journal,” Aug. 31, 1907, p. 320.)

¹⁰ “Bird-lime” in “Pantologia,” Vol. II (1813).

¹¹ “Japanese Bird-Lime,” op. cit.

¹² “Bird-Lime” in “The Domestic Encyclopedia,” Vol. I (1803).

¹³ “On the Composition of Bird-lime” by Edward Divers and Michitada Kawakita in “The Journal of the College of Science, Imperial University, Japan,” Vol. II, p. 17 (1889); and “Elements of Chemistry” by Thomas Thompson (1810).

¹⁴ “Laticifers in Olona and Ulu: Biological Comparison and Ethnobotanical Significance” by Jenny Harvey in “Journal of Young Investigators,” Vol. 2, No. 1, June 1999, at www.jyi.org/volumes/volume2/issue1/articles/harvey.html.

¹⁵ “A System of Aeronautics, Comprehending Its Earliest Investigations, and Modern Practice and Art” by John Wise (1850). I found few U.S. references to birdlime, and this author, an American, refers the substance as rare here in his day. Birdliming is “not an ongoing issue in the USA” today, according to Greg Butcher, the National Audubon Society’s director of bird conservation (Agu. 12, 2010 e-mail forwarded by National Audubon Society spokesperson Delta Willis).

¹⁶ “Analysis of Birdlime” by M. Buillon Lagrange in “A Journal of Natural Philosophy, Chemistry, and the Arts,” Feb. 1806, Vol. XIII, p. 144. This claims to be the first scientific chemical investigation of birdlime.

¹⁷ “Some Account of the Medicinal Properties of the Expressed Juice of Missletoe-Berries in the Treatment and Cure of Facial Neuralgia, and Affections Analagous in their Nature to Tic Douloureux” by R.W. Hardy in “The Medical Times,” April 19, 1845, Vol. 12, No. 291, p. 36.

¹⁸ “A System of Chemistry for the Use of Students of Medicine” by Franklin Bache (1819); and Lagrange, op. cit.

¹⁹ “Birdlime for Catching Rats and Mice,” op. cit. Birdlime use was also referred to in the popular 1812 novel “Swiss Family Robinson,” a remarkably persistent dystopia that stands as one of the most animal-abusive pieces of “children’s” literature (“Swiss Family Robinson” by Johann Wyss, Melvina G. Vogel, ed.).

²⁰ “Making a Home Aviary” by Sophie Almon Hensley in “The Chautauquan,” April 1897, Vol. XXV, No. 1, p. 80-82.

²¹ Harper, op. cit.

²² The quote is from Divers and Kawakita, op. cit.

²³ “Report Upon Foresty” by Franklin B. Hough, U.S. Forest Service (1878).

²⁴ “The Birds of America, from Drawings Made in the United States and their Territories” (Vol. III) by John James Audubon (1841). Audubon praises the goldfinch for what he believes is its learned response in escaping his birdlime trap: “…it throws itself backwards, with closed wings, and hangs in this position until the bird-lime has run out in the form of a slender thread considerably below the twig, when feeling a certain degree of security, it beats its wings and flies off….” Apparently, this means a bird dangled far enough to stretch the glue thin enough to break free. Contrary to his respect for this avian Houdini, I found a report of a goldfinch being trapped with birdlime in Ireland about 50 years later (“Bird Catching at Glengarriffe” by Rob. F. Walsh in “Outing,” April 1890, Vol. 16, No. 1, p. 49-52).

²⁵ Brunner, who works on agricultural policy, told a full anecdote about his father’s region of Italy that reveals some ecological irony: “Back then, wild birds were pretty much the only animal protein the peasants were ever getting hold of to supplement their corn and little else diet (and my dad was joining in for the fun). They were using lime both to catch migratory songbirds in autumn and spring and to catch wintering rooks. And the horrors go on with nets…night spearing of roosting birds, etc. That said, in that area there were far more birds than there are now that all of this [trapping] has stopped, but the whole landscape has been wiped out by a sea of intensively grown corn. Which is less gruesome and makes less headlines, but is a much bigger threat.”

²⁶ “India’s Bird Trade,” op. cit. A rare modern American recommendation for using birdlime can be found in the “U.S. Air Force Survival Handbook” by the United States Air Force (2008).

²⁷ “Migratory birds served in Cypriot restaurants,” March 24, 2009 press release, BirdLife International, at www.birdlife.org/news/news/2009/03/cyprus.html.

²⁸ “Who killed cock robin? The hungry Cypriots did in annual slaughter” by Press Assocation, Dec. 23, 2009, The Guardian, at www.guardian.co.uk/environment/2009/dec/23/robins-cyprus-christmas-slaughter.

²⁹ The products I purchased and examined were Victor’s Fly Catcher flypaper; JT Eaton’s Pest Catchers mouse and roach glue-trap; and JT Eaton’s Stick-Em and Eight Ball’s mouse glue-traps.

³⁰ For example, the package of the Eight Ball brand mouse trap said in English to remove the glue with cooking oil or mineral spirits, but in Spanish to use alcohol. A larger size of the Eight Ball glue-trap, apparently containing the same substance, said to use alcohol in the English instructions as well, with no mention of cooking oil or mineral spirits.

³¹ See www.blackflag.com. That being said, a glue-trap is indeed non-toxic in normal use and appears to be much safer for a household with children than pesticides or snap-type mousetraps.

³² “A Laboratory Test Method for Evaluating the Efficacy of Glueboards for Trapping House Mice” by Stephen C. Frantz and Constance M. Padula in “Vertebrate Pest Control and Management Materials: Fourth Symposium,” Dale E. Kaukeinen, ed. (1983). The authors tested Stick-Em and Trap-Stik brand glue-traps.

Victor, the company that makes the famous standard mousetrap, suggests that glue-traps can be a humane method if you’re willing to dump cooking oil on your captured rodents to free them. I think most trap users will find that both dangerous and infeasible, particularly given the tendencies of mice to be injured quickly by such traps. Meanwhile, Victor is naturally working on building the better mousetrap, and now has one that electrocutes its victims. Surely, a lethal injection model is coming soon. (See www.victorpest.com.)

I should confess here that I once set out a large glue-trap for what I feared was a huge rat crawling in the ceiling of my attic apartment. The beast turned out to be a raccoon, which had a little tussle with my glue-trap but came away unscathed and apparently unimpressed.

Significant sources not cited in the text or footnotes include: “Commission takes action against illegal bird-hunting,” Dec. 12, 2006 press release, European Union, at http://europa.eu/rapid/pressReleasesAction.do?reference=IP/06/1766&format=HTML&aged=0&language=EN&guiLanguage=en; “Compound of Collodion with Bird-Lime” by M. Lemoine in “The Chemist,” 1852-53, Vol. IV, p. 497; “Curiosities of Natural History” by Francis T. Buckland (1878); “Everglades National Park and the Surrounding Area” by Roger L. Hammer; “Fowling” in “Third American Edition of Nicholson’s British Encyclopedia, or Dictionary of Arts & Sciences,” Vol. II, William Nicholson, ed. (1819); “Insecticides, Fungicides, and Weed Killers: A Practical Manual on the Diseases of Plants and their Remedies, for the Use of Manufacturing Chemists, Agriculturists, Arboriculturists and Horticulturists” (2^nd ed.) by Emmanuel Bourcart and Thomas R. Burton (1925); “Law Relating to Animals” by Simon Brooman and Debbie Legge (1997); “The Natural History of Pliny” (Vol. III), John Bostock and H.T. Riley, trans.; “Nature’s Teachings: Human Invention Anticipated by Nature” by J.G. Wood (1907); The Oxford English Dictionary Online database (www.oed.com); “The Seven Books of Paulus Ægineta,” Francis Adams, trans.; United States Department of Agriculture Natural Resources Conservation Service web site citation for Robinia viscose at http://plants.usda.gov/java/profile?symbol=ROVIV; United States Patent and Trademark Office web site at www.uspto.gov (particularly patents numbers 4,244,134; 5,438,792; and 7,401,436); Woodstream Corporation, maker of Victor brand products, web site featuring Material Safety Data Sheets for glue-traps, at www.woodstream.com. All books, journals and magazines via Google Books unless otherwise cited. Posted Aug. 14, 2010.

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