Why Was This Cardinal Carrying a Cigarette? Science Offers a Clue

ALEXANDRIA, VA – Alexandria resident Lucy Goddin recently photographed a female cardinal perched on her back fence in Wilton Woods with a cigarette butt dangling from the side of her beak.

When Goddin shared the picture on social media, she offered a possible—and rather surprising explanation.

“Certain urban birds use discarded cigarette butts in their nests because the nicotine and toxic chemicals act as a pesticide to reduce mites, ticks and other parasites,” she wrote.

As strange as that sounds, there is science behind it. So we dug in to learn more.

A City Bird’s Pest Control?

Researchers at the National Autonomous University of Mexico have documented urban birds using pieces of discarded cigarette filters in their nests.

In a study published in the Royal Society journal Biology Letters, Monserrat Suárez-Rodríguez, Isabel López-Rull and Constantino Macías Garcia examined cigarette-filter material in the nests of house sparrows and house finches.

They found that nests containing more material from smoked cigarette filters generally had fewer nest-dwelling parasites.

The researchers also created heat traps using smoked and unsmoked cigarette filters. Fewer parasites made their way to the traps containing the smoked filters, presumably because of the nicotine and other chemicals left behind.

The researchers called it “the first evidence that smoked cigarette butts may function as a parasite repellent in urban bird nests.”

It may be a city bird’s version of a very old trick. Birds have long been known to bring fresh, aromatic plants into their nests, apparently using the plants’ natural compounds to discourage parasites.

In a city, where cigarette butts may be easier to find than the right herbs, a discarded filter could become an unexpected substitute.

Clever? Absolutely.

Healthy? Well, that is where things get complicated.

No Such Thing as a Free Cigarette

When Suárez-Rodríguez and Macías Garcia returned to the subject, they gave their follow-up study a title that pretty much said it all: “There Is No Such a Thing as a Free Cigarette.”

They found that cigarette-filter material may help reduce parasites, but it can also expose birds to toxic chemicals. Although nests with more cigarette material showed some short-term benefits, the researchers also found signs of cellular damage in the birds.

In other words, a cigarette butt may solve one problem while creating another.

There is also an important distinction. The studies involved house sparrows and house finches, not Northern Cardinals. No one can say for certain whether Goddin’s cardinal planned to use the cigarette in a nest, was moving a piece of litter or simply picked up something interesting.

Still, female cardinals do most of the nest building, and their nests can include twigs, bark, grasses, plant fibers and even the occasional bit of human-made debris.

So was this Alexandria cardinal gathering some unconventional pest control?

We may never know.

As Goddin joked in her post, “Here I thought she had just developed a bad habit…”

𝙀𝙙𝙞𝙩𝙤𝙧’𝙨 𝙉𝙤𝙩𝙚: 𝙒𝙞𝙡𝙩𝙤𝙣 𝙒𝙤𝙤𝙙𝙨 𝙞𝙨 𝙡𝙤𝙘𝙖𝙩𝙚𝙙 𝙞𝙣 𝙁𝙖𝙞𝙧𝙛𝙖𝙭 𝘾𝙤𝙪𝙣𝙩𝙮, 𝙤𝙪𝙩𝙨𝙞𝙙𝙚 𝙩𝙝𝙚 𝘾𝙞𝙩𝙮 𝙤𝙛 𝘼𝙡𝙚𝙭𝙖𝙣𝙙𝙧𝙞𝙖’𝙨 𝙗𝙤𝙪𝙣𝙙𝙖𝙧𝙞𝙚𝙨, 𝙗𝙪𝙩 𝙝𝙖𝙨 𝙖𝙣 𝘼𝙡𝙚𝙭𝙖𝙣𝙙𝙧𝙞𝙖 𝙢𝙖𝙞𝙡𝙞𝙣𝙜 𝙖𝙙𝙙𝙧𝙚𝙨𝙨. 𝙏𝙝𝙚 𝙕𝙚𝙗𝙧𝙖 𝙘𝙤𝙫𝙚𝙧𝙨 𝙩𝙝𝙚 𝙜𝙧𝙚𝙖𝙩𝙚𝙧 𝘼𝙡𝙚𝙭𝙖𝙣𝙙𝙧𝙞𝙖 𝙘𝙤𝙢𝙢𝙪𝙣𝙞𝙩𝙮 𝙖𝙣𝙙 𝙞𝙨 𝙣𝙤𝙩 𝙡𝙞𝙢𝙞𝙩𝙚𝙙 𝙗𝙮 𝙢𝙪𝙣𝙞𝙘𝙞𝙥𝙖𝙡 𝙗𝙤𝙪𝙣𝙙𝙖𝙧𝙞𝙚𝙨.