S4E3 - Pre-Emptive House Finches

House finches in Mexico City use discarded cigarette butts in the lining of their nests to fend of parasites, Herre de Bondt tells us more abut this interesting behaviour and some of its potentially worrisome impacts.

Recorded: 30 October 2023. 

 Featured: 

• All that breathes
• Lively Cities by Maan Barua.
• Killer Cities by Nigel Thrift.
• An experimental demonstration that house finches add cigarette butts in response to ectoparasites by Monserrat Suárez-Rodríguez, Constantino Macías Garcia. 
• Interacting effects of aromatic plants and female age on nest-dwelling ectoparasites and blood-sucking flies in avian nests by G Tomás et al. 
• Incorporation of cigarette butts into nests reduces nest ectoparasite load in urban birds: new ingredients for an old recipe? By Monserrat Suárez-Rodríguez, Isabel López-Rull and Constantino Macías Garcia
• Smoking and Lung Cancer by Tonya Walser et al. 
• There is no such a thing as a free cigarette; lining nests with discarded butts brings short-term benefits, but causes toxic damage by M. Suárez-Rodríguez, C. Macías Garcia
• Mexico tightens ban on smoking in public places by Will Grant on the BBC

Credits:

• Claudia Hirtenfelder, executive producer and host 
• Herre de Bondt, co-host and co-editor
• Christiaan Mentz, sound editor and producer 
• Rebecca Shen, content producer and designer (logo and episode artwork)
• Gordon Clarke, bed music composer
• Learn more about the team here. 

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Chapters

• 0:00 Introduction
• 0:43 All That Breathes
• 4:00 House Finches
• 6:00 Fending off parasites in Mexico City
• 9:00 The negative consequences of cigarettes
• 11:00 Urban Policies and Animals
• 13:53 Credits

Transcript

 00:00 – Introduction

• Season 4 of The Animal Highlight: Animals and Waste. 
• Co-host this season: Herre de Bondt has done research on rats in Amsterdam, crows in Tokyo, and gulls in The Hague. His work has now brought him to London where his PhD project is concerned with urban bird feeding practices. From hanging up fatballs for chirpy robins to tossing seed to flocks of ‘flying rats’, Herre is determined to investigate the inherently multispecies practice of bird feeding. He is particularly interested in the ways non-human animals inform and shape the contemporary city in collaboration with – and in defiance of – humans. You can connect with Herre via Twitter (@HerreBondt). 

00:43 – All That Breathes

• I recently watched a documentary called ‘All That Breathes’, which depicts two brothers in New Delhi who dedicate every waking hour to rescuing and nurturing Black Kites back to health. Their goal is severely impacted by the political landscape in the city, by air pollution that poisons the sky and the birds, and by their financial situation. I definitely recommend watching All That Breathes because it beautifully illustrates how multispecies relations allow us to see the city as a complex ecology, full of resilient life. 
• Lively Cities by Maan Barua and Killer Cities by Nigel Thrift 
• Something that stood out for me when watching this film was when one of the rescuers mentioned that Black Kites in New Delhi have started rubbing cigarette butts in their nests as a type of anti-parasite coating. Eager to find out more, I jumped on the computer and rammed in the search term ‘black kites cigarette butts New Delhi’ but no matter how many variations of that I tried, I couldn’t find anything published about black kites engaging in such behaviour. 
• However, this search took me to the other side of the world, to Mexico City. Here, researchers have found that a far smaller bird, the house finch, is indeed collecting cigarette butts and lining their nests with it. So that’s what I am focusing on today, house finches and their use of cigarette butts. 

04:00 - House Finches

• House finches are small birds, no longer than let’s say a standard tube of toothpaste. They originally came from Mexico but now live across North America. Like many finches, they have a short beak, black, bead-like eyes, and a beautiful song made up of short notes. Both male and female birds are light brown with darker brown stripes on their bellies and sides. Male House Finches, however, look like they’ve been sprayed in the face by a graffiti artist as a red, mist-like colour covers their heads and bellies. This make-up is a result of the berries and fruits that they eat, and female House Finches are far more attracted to deeper red colouration than to other colour. 
• We all know what happens after the female bird takes a liking to a male bird, so I’d like to fast forward to what happens when these birds are ready to start building a nest. 

06:00 – Fending off Parasites

• Researchers found that certain birds, like starlings, collect aromatic plants, like yarrow, and weave them into the lining of their nests to fend off ectoparasites such as fleas and ticks, but especially the nest mite. Ectoparasites not only suck blood, but also spread endoparasites that can be even more harmful to nestlings as they wreak havoc inside of their bodies. Now the ornithological world is debating why exactly birds weave plants into their nest. The question is: Do birds actually do this to deter ectoparasites from entering their nest? 
• Whatever the reason may be, house finches in Mexico City seem to have swapped their herbal treatment for a more questionable habit of lining their nest with cigarette butts. 
• Whenever I think of urban waste, cigarette butts come to mind. This disposed final bit of cigarettes has become so ubiquitous that I personally barely even notice them anymore. But house finches do! They have become so aware of cigarette butts that they capitalize on this human litter. Monserrat Suárez-Rodríguez and Constantino Macías Garcia, researchers at the National Autonomous University of Mexico, conducted a series of studies to investigate how house finches interact with cigarettes. The team found that smoked cigarette butts did indeed lower the amount of ectoparasites present in the nest. The researchers did, however, say that the birds might merely be using the cigarette butts as insulation. 
• Clearly not wanting to let the matter rest, Suarez and Garcia carried out another study five years later. This time they added live and dead ticks to the house finch nests to see how the house finches would react. And they were right, the presence of ticks did indeed spur the female finches to weave more smoked cigarette butt fibers into their nests. 

09:00 – The negative consequences of cigarettes

• But there is a reason why we tell children ‘don’t smoke!' Cigarettes are addictive and detrimental to the human body. Smoking remains one of the leading causes of lung cancer, for instance. While we don’t see house finches going around smoking these cigarettes, surely interacting with them can’t be good for small passerine birds either. 
• In 2017, the same team of researchers discovered that the cigarette butts were indeed affecting the nucleus of the blood cells of birds who spent a lot of time in nests with cigarette butts. The long term effects of this remain unclear but it does mean that female finches are disproportionately exposed to this risk as they spend more time in the nest than males do. This also shows how the geographies of waste can have impacts that cut across species and gender lines. 
• It’s interesting to think about how our waste carries over beyond human worlds. When we speak of recycling, reusing, or upcycling we talk about it in terms of how waste can retain or regain value to human societies. Discarded and used cigarette butts arguably have little value to humans but house finches show us that this waste can still be useful. It remains to be seen if this resource is, however, harming them. 

11:00 Urban Policies and Animals

• This also makes me think about the more-than-human consequences of shifting human habits. As Mexico City’s population started smoking more and more, house finches collectively started using cigarette butts in their nest construction. 
• Now, as of 2023, Mexico has announced a smoking ban in many public places that is so strict the BBC has dubbed it ‘one of the world’s strictest anti-tobacco laws’. Needless to say this will significantly impact the availability of cigarette butts for house finches, how will this change their habits and what other materials might they start using as nest-building material? Who knows? But I am sure we are bound to be surprised by their resourcefulness once again. 
• There is no tobacco in the filter but does pass through the filter. 
• House finches are choosing to use cigarette plant instead of tobacco plants, this raises more interesting questions. 

13:53 – Credits

• The Animal Highlight is produced and hosted by Claudia Hirtenfelder. This season was co-hosted with Herre de Bondt. The editing was done by Claudia Hirtenfelder, Herre de Bondt, and Christiaan Mentz. The episode artwork was done by Rebecca Shen and the best music by Gordon Clarke.