Fig. 1 American Robin nest, made of twigs and mud (Source: Mark on Flickr https://www.flickr.com/photos/eggrole/7213149990/, photo rotated by Kit Straley).
Birds can build their nests out of many different things – from the classic combination of twigs and mud to more creative compositions of grasses and even fresh plants. Birds that nest in urban places like cities or the surrounding suburbs have access to entirely different building materials for their nests: our trash.
Fig. 2 A bird nest with trash built in (Source: k.steudel on Flickr https://www.flickr.com/photos/snaks/3453764253/).
But why build a trash nest when twigs, grasses, and mud are still available choices? A study  by Suárez-Rodríguez and colleagues from the National Autonomous University of Mexico indicated that some trash could have benefits for chicks that grow up in the nest. Specifically, they investigated the use of cigarettes in bird nests and how the presence of cigarettes decreased parasites.
Parasites are creatures that live on other plants, fungi, or animals and are harmful to them. In birds, ectoparasites (parasites that live on the outside of the body) can have severe negative health effects on their hosts. Ticks, lice, and mites are just some of the ectoparasites that birds have to live with, even in the nest. These unwanted guests latch on to their hosts and live off of their blood, sometimes even killing their host .
Fig 3 Field Sparrow with 2 ticks on its face (Source: Alan Schmierer on Flickr).
Some birds combat this parasitic invasion by including fresh aromatic plants (plants that emit strong smells, like mint) in their nests. The plants contain chemical compounds that can deter or kill the parasites . Yes, that’s right, birds know how to fumigate.
In urban areas, aromatic plants may be few and far between but cigarette butts are abundant. Two bird species, the house sparrow and the house finch, have been observed using cigarettes in their nests . Suárez-Rodríguez’s team wanted to know if house sparrows and house finches in Mexico City were using our discarded butts to protect their chicks from harmful mites.
Fig. 4 A cigarette pack discarded in the woods (Source: StockyPics on Flickr).
The scientists used traps to capture ectoparasites around bird nests. Traps were baited with fibers from smoked and unsmoked Marlboro cigarettes, as smoked butts would release more anti-parasite chemical compounds like nicotine. At the end of the nesting period, they collected nests and parasites to see if nests with more cigarette fibers had more mites.
Fig. 5 Cigarette fibers and filters built into a swallow nest (Source: Bear Paw Battlefield on Flickr https://www.flickr.com/photos/bearpaw/5910472344/)
And the cigarettes worked! Nests with more cigarette fibers had fewer ectoparasites, and traps with smoked butts had fewer ectoparasites than traps with unsmoked butts. Surprisingly, over 80% of both bird species’ nests had cigarette fibers in them, and some nests had over 30 cigarette butts in them !
Am I recommending that we go around disposing of our cigarettes in bird nests? Of course not. Twiggy nests are basically piles of kindling, and that would be horrific. I don’t recommend littering cigarette butts either. The results of the study do show surprising beneficial uses of human litter in a world where our trash is almost exclusively bad for wildlife.
 Suárez-Rodríguez, M., I. López-Rull, and C. Macías Garcia. 2013. Incorporation of cigarette butts into nests reduces nest ectoparasite load in urban birds: new ingredients for an old recipe? Biology Letters 9(1):20120931. http://dx.doi.org/10.1098/rsbl.2012.0931
More From Thats Life [Science]
- Do we have all the data needed to make safe choices about seafood?
- Is it possible to eat too much fish?
- Single Large or Several Small? The Ongoing Debate in Nature Preserve Design
- Moving away from monoculture in aquaculture
- Some people just love plants (as long as they can afford them...)
- Life on the Edge: 3 Important Ways that Habitat Edges Affect Forests
- Are we running out of invasives?
- Ask your food for its DNA ID
- Finding wildfire’s niche in the Anthropocene
- The Earth is a blue marble (and the world is green)
- Four Unexpected Ways that Living in Cities Affects Wildlife
- Celebrating 117 Years of Christmas Bird Counts · 'Tis the Season for Citizen Science
- Why fish deserve our research money · Fish are friends AND food
- Integrating knowledge of microbial ecology into building architecture. · Building with Microbes (In Mind)
- Halloween Tales from the Ocean · A thorny, venomous creature is terrorizing coral reefs
- The magic of in-between places along the Appalachian Trail · Walking through Transitions
- How are forest insect outbreaks like wildfires?
- Sharing the ecosystem with wildlife - why getting outside is more important than ever
- How Mercury in Fish Could End Up in Your Dish · The Mercurial Path of Mercury to Aquatic Ecosystems
- Nicotine Dreams - Baby Birds Protected by Cigarettes
- A reflection about the value of water and the forest · Drinking from the rivers and eating from the forests
- Good intentions sometimes lead to unfortunate outcomes · 4 ways humans harm the environment (when they are trying to help)
- Catch-and-release anglers catalyze conservation for the prized golden dorado fish · Fishing Towards Conservation
- Marvel at Larval - An Appreciation for Young and Developing Fish
- Some Australians consider kangaroos to be pests. Surprised? So was I.
- A World without Birdsong
- A closer look at species diversity in the tropics · It's Standing Room Only At The Equator
- More ›