Birders are a curious bunch. There are many millions of them in the world, and they range from mildly to severely obsessed with all things birds. Few things inspire such fevered participation by the fervent, and such bemused wondering by the uninitiated. Who else gets up on purpose at 4 AM on a non-workday? Birding can be a pretty minimalist hobby--you don't need much to watch birds, though a pair of binoculars is nice. Indeed, you don’t even need to see to be a good birder. [Birdwatching does have an unfortunate diversity skew--here's a funny post on that]. Despite that, there is no shortage of ways birders can spend their money. And spend it they do--a 2013 US Fish & Wildlife study estimated birders spend $107 billion/year on their pursuit of our planet's feathered denizens. Pretty cool if you ask me. Like I said, birders vary in the severity of their avian afflictions. There is a subset, not insignificant in absolute numbers, of people who know which birds they've seen, which birds they haven't seen, where those birds live, when to find them, and how to find them...in short, there are at least a couple hundred thousand people in the US who when I say, "there's a Rustic Bunting four hours away", respond, "get in the car." Given that mass of educated, passionate, motivated birders, one might think that there are no new ways to consider which birds one has or has not seen. But, after some discussion with various folks recently who have also had these ideas, it occurred to me that one aspect of birding has not been well explored outside of a few science nerd types. What I'm proposing here is a phylogenetic life list. In this context, evolutionarily unique species are "worth more". You might have been excited this spring when you ticked your first Golden-winged Warbler, but let me temper that enthusiasm for you. What you saw was, in an evolutionary sense, barely distinguishable from a Blue-winged Warbler (Toews et al. 2016). Come talk to me when you've seen a Kagu in the mountains of New Caledonia. Playing this sort of listing game, all new species (branches on the evolutionary tree) count towards your phylogenetic life list, but evolutionarily unique species count more. Put differently, seeing a Golden-winged Warbler (or a Kagu) ticks off one of the ~10,000 bird species to see globally under a traditional counting strategy (0.01% of all species to see in the world). But, under a phylogenetic life list strategy, seeing a Golden-winged Warbler ticks off just 0.003% of global unique evolutionary diversity, while seeing a Kagu adds 0.13%! I should digress and say taxonomy is hard. Converting the taxonomic concepts in my eBird life list to the taxonomy used by the Jetz et al. (2012) world bird tree took me a week's work. After that though, the rest was pretty easy. For the purposes of this post, there are two ways to consider evolutionary uniqueness. The length of the pendant edge of the species in question, and the mean relatedness of that species to all others. The pendant edge describes the amount of time that branch of the tree of life has been evolving on its own path (all caveats about extinction aside). Take the Kagu. It's evolutionarily unique according to this measure because its closest extant relative is the Sunbittern. They last shared a common ancestor 63 million years ago. Seeing a Kagu is kind of like seeing a velociraptor. In contrast, the mean relatedness describes the average evolutionary distance of a species to all others. In this context, species like tinamous and ostriches are even more evolutionarily unique than the Kagu, because tinamous and such are distantly related to the vast majority of other birds. I've made some visualizations to go along with this idea. This first one shows the world bird tree, pruned to the bird species that I've seen (according to eBird and as converted to world bird tree taxonomy). The evolutionary uniqueness of these species, according to the pendant edge method, is color-coded on there. I've also stretched branches out as a function of the pendant edge, so that evolutionarily unique species are colored in yellow, and are situated on long spines out from the tree. A friend affectionately called this an urchin plot. The plot is too low-resolution to zoom in, so I'll narrate it for you. At 3 o'clock are the Ostrich and Emu, and at 4 o'clock are the Sunbittern and Oilbird. Over at 8 o'clock is the Sapayoa. [I'm 100% convinced that there is a tight correlation between one-word bird names and evolutionary uniqueness, much like the tight correlation between one-word soccer player names and soccer skill]. This second one shows the evolutionary uniqueness of all the species I've seen according to the mean distance measure. Here, tinamous and the like are really unique, whereas passerines, which comprise the bulk of avian diversity are not. Last up is the entire world bird tree, with species I have and have not seen color-coded according to their (pendant edge) evolutionary uniqueness. Gray = not unique, I have seen it. Black = unique, I have seen it. Blue = not unique, I have not seen it. Yellow = unique, I have not seen it. Because it's such a large file, and I'm just adding a jpg of the zoomable pdf, I've added a few screenshots here to get a better sense of what's going on. I see some obvious extensions of this. First, to return the hordes of interested birders, it would be pretty amazing to be able to generate these sorts of plots for any user of eBird, and serve these up in a more interactive setting. I think it presents some great opportunities for helping people to think about evolution and practice tree-reading skills. I'm thinking OneZoom-ish. Second, it would be really interesting to be able to put the phylogenetic life list in a geographic context. For instance, where on Earth should I go to see the most novel phylogenetic diversity in the most geographically constrained area? Or, if I visit my aunt in southern California, what would be the most evolutionarily unique species I might see?
Literature cited: David P.L. Toews, Scott A. Taylor, Rachel Vallender, Alan Brelsford, Bronwyn G. Butcher, Philipp W. Messer, Irby J. Lovette. 2016. Plumage Genes and Little Else Distinguish the Genomes of Hybridizing Warblers. Current Biology 26:2313-2318. DOI: http://dx.doi.org/10.1016/j.cub.2016.06.034 W. Jetz, G. H. Thomas, J. B. Joy, K. Hartmann, A. O. Mooers. 2012. The global diversity of birds in space and time. Nature 491: 444-448. doi:10.1038/nature11631
9 Comments
10/9/2017 09:58:44 pm
This is actually a perfect use case for our NSF-funded ABI project: phylotastic (for creating an infrastructure for sharing the tree of life), especially the datelife.org part (to get a tree with branch lengths). We're still working out some integration issues, but pretty soon (on the order of a few months) this should all be largely debugged: go from a list of birds to a chronogram (esp given the various source chronograms already available). Let me know if you want to coordinate on this.
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Eliot
10/10/2017 09:04:42 pm
Brian, that's exciting. This is actually the backstory here--I'm exploring these ideas as part of a potential informal science learning proposal for 2018. Whether I submit that or not is TBD, depends on a few things. In the meantime, there are some aspects of this going into a related proposal now-ish. Let's talk more. PS. sorry it took me 24 hours to respond, apparently I don't get notifications about my blog posts.
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10/10/2017 10:11:12 pm
The proposal sounds good -- definitely a lot of room in this space for improvements. For the taxonomy, the taxize and rotl R packages can do name resolution -- not as well as by hand by an expert, but perhaps could save a fair bit of time.
Elena S Ruiz
10/10/2017 10:10:07 am
Working with Jetz' phylogeny and feeling your pain with regards to translating current species into 2012 species concepts!
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Eliot
10/10/2017 09:06:50 pm
Oh my god it's rough! I spent forever working on it. I think I'll post the conversion table I made soon, just to help people out later. It's only about half of the species, but if I can save someone a week of googling it seems like a good idea.
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Petter Zahl Marki
10/11/2017 08:21:50 am
Cool stuff!
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Eliot
10/13/2017 11:49:10 am
Thanks!
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11/11/2017 11:03:46 pm
Those are great visualizations!. Couldn't agree more with you that birders would get into a phylogeny app. My colleague Sebastian Pardo and I (both birders) have been working on a shiny app that is along the lines of what you are working on, designed to be accessible to a general audience. You can see the latest version on the website provided. Check it out, we would love to talk more about the idea.
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Eliot
12/22/2017 04:10:49 pm
I'm excited to see this! Like I said to a comment above, sorry for the delay in writing back to you. Weebly isn't delivering me notifications about the blog. I googled your project and found it. It looks like you all have made major inroads on this already. I really like the page, and it's great to see how much you all have done already! I think people will really like this sort of thing. Let's talk more.
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