Birds Using Cigarettes To Build Their Nests in Mexico

In what is both a display of ingenuity but also a troubling sign of how humans’ carelessness can affect the habits of wildlife, house finches (C. mexicanus) and sparrows (P. domesticus) in Mexico City are using cigarette butts to ward off parasites from their nests.

Yes, birds are turning to cigarettes to protect their nests.

As reported in Biology Letters, scientists observed birds on the grounds of the National University of Mexico “routinely pulling apart cigarette butts to obtain the filters.” Noting that the birds used the filters in building their nests, Constantino Macias Garcia of the National Autonomous University and his colleagues monitored 57 nests and discovered that, the more smoked cigarette butts per nest, the fewer the parasites.

The sparrow nests contained an average of eight used cigarettes and could have between none and 38. The finch nests had an average of ten used cigarettes, and could have from none to 48.

Life Lines at Science Blogs describes how Garcia and his team found that the smoked cigarettes were more effective in deterring parasites:

Using heating elements to attract parasites, they found that probes covered in “used”, i.e. artificially smoked, cigarette butts attracted fewer ectoparasites than those that were not used. These observations suggest that the birds may be using discarded cigarette butts, which collect chemicals like nicotine, for pest control in their nests.

Nicotine and tobacco indeed have been used in some insect repellents for crops and in warding off poultry parasites.

The cellulose from the cigarettes also helps in insulating the birds’ nests. The finches and sparrows have certainly adapted to their urban environment. Some birds who live in more natural settings use aromatic plants to line their nests, both also, it is thought, to guard against parasites and boost their chicks’ immune systems.

But while the Mexico City birds may be protecting their young from pests, there are certainly side effects from their choice of materials. Comments Life Lines at Science Blogs: “Since eggs are rather porous, the potential health risks for cigarette butt-insulation on developing embryos or adult birds are currently unknown.”

It’s been found that sparrows have to raise the volume of their tweets to be heard in cities due to noise pollution. In Mexico City, in an effort to protect their eggs and chicks, finches and sparrows could also be exposing them (and themselves) to something like second-hand smoke in nests that are less safe than intended.

Related Care2 Coverage

Sparrows Tweet Louder To Be Heard in Noisy Cities

Noise Pollution Turns Urban Birds Into Bad Parents

Boring Cigarette Packaging: Enough To Stop Teens From Smoking?

Photo by surtr


.2 years ago

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Alina John
.2 years ago

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Fiona T.
Past Member 5 years ago

This is disgusting though it shows how the animals' and human world interacts

Carrie Anne Brown
Carrie-Anne B5 years ago

thanks for sharing

Rosemary H.
Rosemary H.5 years ago

Michael H, why do people have to fall over backwards trying to deny the intelligence of animals?Read 'King Solomon's Ring' by Konrad Lorenz. He won the Nobel Prize for his studies of birds and animals who were certainly smart enough to do this sort of thing.

Yes, clever birds to figure out that tobacco keeps insects and other forms of buglife away. I wrote more than this about the health risk - horrible computer just lost it...

Diane L.
Diane L5 years ago

Okay, who is going to alert the writer of this article about her lousy spelling? What is a bird's NEXT?

It's alarming that birds would be picking up cigarette butts anywhere. I am not a smoker but used to be. One of my biggest annoyances even AS a smoker was anyone who discarded a cigarette butt in an inappropriate place. The fact is that they take about 20 years to decompose.

Beth M.
Beth M5 years ago

Cigarettes are bad for every living thing. Careless, self-centered humans.

Celine R.
.5 years ago

Pollution is overrunning their environment; these birds are forced to adapt with what they can find.

Marie Therese Hanulak

Smart birds.

Karen M.
Karen M5 years ago

I love the story and would like to share, but I admit embarrassment from the misspelling of nests in the headline. Please correct this and I will definitely share! :)