Back yard cats, balloons, and butterfly releases

Image: Balloon release at the Yarmouth Old Gaffers Festival, by Editor5807 CC BY 3.0, via

Someone’s cat just wandered across my back yard, and that got me thinking about butterfly releases.  No, really – stick with me for a moment.  There’s a connection, and, eventually, a bigger point.

By now, everyone ought to be aware that letting domestic cats roam outdoors is a terrible idea.  It’s terrible for the cats, who live shorter and less healthy lives; but much more important, it’s terrible for wildlife – cats kill millions of songbirds each year, and have (on islands) even been directly responsible for bird extinctions.  That there are self-identified cat “lovers” still insisting on letting cats outside says a lot about the phenomenal ability of humans to avoid (often deliberately) the acquisition of knowledge.  But this post shouldn’t become a rant about cats, so I’ll move on.

Balloon releases have more recently come under scrutiny, and it’s pretty obvious that they’re also a terrible idea. 

If you wanted to celebrate something by deliberately littering on an epic scale (sounds bizarre put that way, doesn’t it?), you’d be hard pressed to design something better than a balloon release.  Balloons can travel hundreds of kilometers, and neither they nor the ribbons they often trail biodegrade in any hurry.  They’re unsightly and they’re dangerous, choking or entangling wildlife.  That we ever thought balloon releases were a good idea says a lot about the way humans can be (often deliberately) completely oblivious to the downstream consequences of their actions.

And this brings me to butterfly releases.  These have become common as a supposedly green alternative to balloons, especially (for symbolic reasons that make an odd juxtaposition) at weddings and hospice memorials.  There are multiple vendors who will sell you live butterflies for a release; the butterflies are normally farmed and shipped shortly after eclosing as adults.  (Painted ladies and monarchs seem to be most common in North America.)  Everyone loves a butterfly*, and releases are depicted as a way to celebrate without the environmental damage of balloons – or even while giving butterflies, or pollinators more broadly, a hand.

But butterfly releases aren’t a good idea (environmentally); they’re a bad one.  There are at least four reasons.

    • First, releasing butterflies that were reared in captivity somewhere else risks spreading disease into native populations.
    • Second, butterflies from captive stock won’t be locally adapted (either physiologically or genetically) to conditions where you release them; the image of them happily fluttering away to live and reproduce in their new home is, I’m afraid, unrealistic.
    • Third, if the released butterflies do survive and reproduce they contaminate the genetic record of that species’ biogeography. We use geographic pattern in population genetics to study things like dispersal, range shifting in response to climate change, post-glacial recolonization, and the evolution of new geographic or host-associated races – the origin of new biodiversity within species.  This signal is muddied or lost when genes (neatly packaged into butterflies) are transported across thousands of kilometers by the butterfly-release industry**.

    • Fourth, if butterflies are released outside the native range of their species, that’s a potential biological invasion. We can point to many, many past deliberate releases that have resulted in invasions with horrible economic and ecological consequences.  Think about Asian carp in North American waters, rainbow trout just about everywhere, and goldfish likewise – and that’s just fish, and just the first three that came to mind.  (If cats were fish, they’d have headed my fish list.  Although if cats were fish, they’d look pretty funny.)  And releases of native species don’t escape this criticism, because they serve to normalize the idea of releasing live animals into the wild.  With the exception of professionally designed restocking-from-captive-breeding conservation programs, releasing farmed animals into the wild is pretty much always a bad ecological idea.

With these arguments established, I bet you’re waiting for me to close on a note of “Please, for the love of all that is holy, stop releasing butterflies”.  And perhaps I should; but I worry about doing so.  I worry because I think there’s a finite reservoir of what I might call environmental enthusiasm; and if I draw down that reservoir combating butterfly releases, I’ll leave less for the more important fights against balloon releases, and outdoor cats, and fossil-fuel consumption.  (This has sometimes been called “green fatigue”, although a Google search suggests use of the term has declined – suggesting a case of “green fatigue fatigue”.)   So I’m inclined to give butterfly releases a gentle pass: to explain, when asked, why I don’t like them, but to stop short of a full-on campaign.

I suspect this will raise hackles in some corners; it’s easy to find folks insisting that we should and can take on every environmental problem at once.  I think that’s where the advocacy of plastic-straw bans is coming from.  There’s no conceivable way plastic straws make even a list of our top 1,000 environmental problems; so whether we agitate against the straw*** depends on whether being asked to do one thing for the environment energizes people to do the next thing, or does the opposite.  Humans being humans, I know which way I lean, so I don’t want to let the perfect become the enemy of the good.  Keep your cats indoors, don’t release balloons, and above all else, reduce fossil-fuel use; and if folks do those things but also release a few butterflies, well, I can grit my teeth and live with it.

© Stephen Heard  October 11, 2018


*^Which is a bit odd, really, given that everyone emphatically doesn’t love an equally colourful beetle or wasp or cockroach.  (Yes, there are colourful cockroaches.)  But any attempt to explain this would quickly run into the same issues as attempts to explain the beauty of flowers.

**^This concern is mitigated to some extent if the released species is migratory.  Monarchs, for example, migrate thousands of kilometers under their own power, with genetic mixing every year in their Mexican overwintering grounds.  It’s still true, though, that there are interesting and important questions to be studied in the way monarchs respond to recurrent selection each year on their multigenerational trip north.

***^Strictly for environmental reasons, I mean.  There are many people for whom various disabilities make straws an important assist, and a straw ban (if we had one) would need to be carefully thought out to avoid disadvantaging the folks who need them.


5 thoughts on “Back yard cats, balloons, and butterfly releases

  1. Martin Vuillème

    I had never heard of butterfly releases before, surprising idea indeed. If I dare, it appears to me that point 3 is only bad for researchers? And wouldn’t they also broaden the genetic pool if they mate with the locals? Or spread some of their immunities this way too? On a side note this got me interested in positive invasions, is that a even a thing? How could we recognize a positive invasion? Are they common? Forgive me if my questions look a tad stupid, butterflies aren’t exactly my area of expertise 😉


    1. ScientistSeesSquirrel Post author

      Excellent points, Martin. I’d say point 3 is directly of interest only to researchers; but of course, society has an interest in the results of that research. As to your second point: introducing more genetic variation can be either good or bad for populations, but since the exotic alleles are likely to be better adapted elsewhere, we might lean to expecting bad outcomes. Finally: positive invasions – absolutely those are a thing, but the key question is “positive for what”? Particular ecosystem services could well be enhanced by an invasion, even while a local species is driven extinct, so it depends how you balance those. Think about introductions of exotic game fish, or there’s another example here:

      Thanks for commenting!


  2. Peter Apps

    An even stronger reason for not releasing balloons is that they are filled with helium, which is a finite resource and needed for serious applications in laboratories and hospitals. Banning helium for recreational balloons would solve two problems at once.

    Liked by 1 person

  3. Macrobe

    Not to nitpick, but numerous generations of butterflies reared during one season and sold like livestock -aka ‘farmed’- are the real issue. Many educators and citizen scientists collect a few to a dozen or more larvae from their local areas and rear them responsibly, usually enclosed in sanitary shelters outside where they are exposed to ambient temperatures and light, and use local milkweed species for developing larvae. Most also participate with Monarch Watch in tagging the eclosed adults before releasing.

    This is hobby captive rearing on a small scale and less likely a significant problem or jeopardy to the entire monarch population. I realize that several of the monarch researchers (such as Andy Davis) and conservationists oppose any and all captive rearing by the public. However, not all are opposed; they recognize that small scale hobbyist captive rearing that follows recommended guidelines helps educate people of the species plight, in addition to serving as entomology lessons. (I refer folks to the research and work of Dr. David James at WSU.) Nor does the small population of responsible hobby rearing jeopordize the overall monarch population. Disenfranchising this could do more harm than good.

    The real threat is the large scale mass-rearing farms that sell all life stages around the country. Already, a few US states legislate against importing and exporting any butterflies without a permit, and butterfly ‘farms’ are illegal.

    Liked by 1 person


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