Pan-species listing, and its role in iNaturalist

Listing was popularized by birdwatchers who wanted to keep track of all the bird species they had, and had not, seen. Less known is “PSL” which stands for “pan-species listing”, in other words, “listing of all categories”. The term originated in England – although not in popular use overseas yet, a number of us are genuine “PSLers”.

Most PSLers lamented the lack of a resource to keep track of their sightings, but iNat is pretty much the perfect answer to that.

If you are an active “PSL” lister, you are probably somewhat aware of what you have or haven’t seen, and finding new species is at least a partial motivation. Whether you intentionally keep a list or not is moot since iNat keeps that for you. There are no strict rules with PSL listing, as it is your personal list – however, it does imply a list of wild organisms, not garden plants or captive organisms.

A few discussion questions (you don’t have to respond to them all, or any of them). Does this sound like you? If so, do you find that searching for species you’ve never seen before encourages you to use iNat more? Would you post things on iNat that you might otherwise overlook or swat away e.g. ticks, mosquitos, shells? Is iNat more important to you as a way to submit data, or as a personal way to keep track of what you see?


There are many questions here. To answer your last, it’s far more important, for me, as a repository to submit data. But there’s no question that listing helps me organize my learning, keep track of possibilities and things I haven’t seen and would like to, and direct efforts to see those as-of-yet-unseen species. It also gives me hope of eventual ID for taxa and locations for which I formerly had no real hope.

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I think this is quite a fascinating concept. In one sense, it’s what I do now, tho I never had a name for it. Mind you, I don’t really have targeted life list (like having to see all the birds in the world). I’m also interested in inventories of all the observable life in given places.

Yes. Emphatically!

Absolutely. Before iNat, I might have occasionally done an interesting bug or butterfly, but it was really all about flowers. Not even plants, particularly, but flowers, and definitely more on the artistic side. Now, not only do I find myself taking pictures of more, I find myself noticing things I never saw before.

Not only would I, I do! I photograph pretty much anything that doesn’t run away fast enough lol.

This is more nuanced for me, I think. I do love having a searchable, tagged database of my own pix, and the chance to have much more IDed than I could ever do on my own is wonderful. On the other hand, I really enjoy the social aspects, as well as the citizen science aspects. I’ve also discovered a love for identifying. In fact, I want to spend all my time identifying. And spend all my time uploading old pix. And spend all my time out observing.

The dilemma is extreme. On the other hand, there are worse problems :-)


I first joined inaturalist because I wanted something online to keep track of my bird lists. When I found ebird I left for a while until I wanted something other than an excel spreadsheet for my herps, mammals, and fish list. I tried keeping excel lists for all life but I found I didn’t have any interest in my invertebrates list and plant taxonomy isn’t my thing. Luckily inat keeps track of them for me in case I do eventually get more interested in them.

I like iNat for keeping track of what I see. I love PSL, but honestly, I love iNat for allowing me to identify things.

I think I’ve heard of the same practice under a different set of initials: OCD.

lol, I’m kidding (sort of).

Seriously, though, I think of myself as primarily a birder, but I do keep a herp list, a mammal list, and I’m detecting a disturbing new interest in moths on my part. I was hoping for iNaturalist to become my eBird equivalent for other taxa. So far, I’m undecided, but enjoying myself here.

Does this sound like you?
If so, do you find that searching for species you’ve never seen before encourages you to use iNat more?
Would you post things on iNat that you might otherwise overlook or swat away e.g. ticks, mosquitos, shells?
Is iNat more important to you as a way to submit data, or as a personal way to keep track of what you see?
More the former, but I expect that if I get the luxury of moderately lucid final years, I’ll treasure the list of what I saw during my time wrapped in the mortal coil.

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I feel it’s because of my ability to do so through a network of experienced people with the ability to aid in identification as well as quickly view taxonomic relationships that encourages me to do the searching. Prior to iNat I had interest in stepping out of my comfort zone, but find it hard to learn without confirmation or feedback.


A bit of both. I’m in a region where my observation are typically on the edge of ranges with low to zero near by observations which I personally feel can help fill out missing information.

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Me, I’m an ex-stamp collector, so I like lists, and sets, and just like stamps to me were little pieces of art, each with a story to be researched for it’s learning opportunities, each taxa, and especially interactions, are my new learning opps… :)


Yes, yes, yes. I use it more as a way to keep track.

I find I keep buying new field guides to keep the potential lifers I could encounter up. (I have mined all the easy birds, butterflies and dragonflies). This year I bought Sedges of the Northern Forest and Field Guide to the Flower Flies of Northeastern North America. I much prefer field guides that have complete species coverage although I did get Beetles of Eastern North America last year.

Some areas are harder to break in. Moss are tough, fish require special provisions, orthoptera require better field guides, etc. I will likely never bother with some groups – black flies for example. I am happy to have that guide to flower flies for sure.

It occurs to me going for all species has a synergistic effect. For example, knowing where to find certain plant species could boost your chances for finding less common butterflies.


It didn’t used to, but its starting to now that I discovered life lists. I am in general more likely to post an organism that I haven’t posted before, both to confirm what it is, make sure its documented in the area, and to add to my life list.

Using iNat encourages me to search for species I’ve never seen before. Through scanning other users observations, I learn what findable in the area that I would have never thought to look for. I didn’t know cladonia lichens existed, not wasp-nest slime mold, or dozens of other species I recognize when I see them in person for the first time because I have seen them in other local observations.

110%. I mostly paid attention to what was in bloom before, and now I am excited about mushrooms, slime molds, Cladonia lichens, teeny tiny spiders, and surprisingly iridescent beetles I find in my kitchen. :D

The fact that the observations I submit become part of a database accessible to scientists is probably my biggest driver to participate in inat, and a big selling factor when I tell my friends and coworkers about it. That being said, I watch my observation and ID count pretty closely, and try to keep a 1:10 observation to ID ratio just because, so the personal gratification plays a role.


Absolutely! Before I started using iNat not so much, but now that I can see the number go up I’m all about it!

In part its searching for new species, in part its just going out and exploring, and getting excited about something I didn’t even know was there! Sometimes I’ll go to a certain location hoping to find something in particular, but usually I am all about the mystery of what I’ll see on that new day.

iNat made me stop killing mosquitos almost entirely because now I’m more interested in them even if I don’t like their bites. I Before I used to shy away from leeches but now I get excited when I see them. The world is my frontier and those “nasty” or “annoying” species are a part of it!

I really use iNaturalist for both purposes. When I see a species in my area that seems poorly represented that I see often, then I try to represent that by observing it myself. However when I see a species I haven’t before I will completely forget about that thing I’ve seen a hundred times to go look at it. Data on any species is important though and so I never mind adding more to better represent it.


“There are no strict rules with PSL listing” And may it always stay this way! The ‘official’ rules for bird listing annoy me intensely. I’m looking to identify and track what is here, whether or not it meets the rules for established populations, etc. [Stepping down from soapbox now.]

“If so, do you find that searching for species you’ve never seen before encourages you to use iNat more?”
Absolutely. What especially encourages me is the possibility of finding ID’s for these species. Not only do I not know anything about flies, I don’t even know how to start learning about flies. But I’m slowly learning more (and enlarging my library) because of the ID assistance here.


yeah i use strict and exacting protocols sometimes. When someone is paying me :) My inat is for biodiversity research but it’s also for my enjoyment, anything onerous or annoying i save for work time (if it’s relevant to assessing wetlands, otherwise i just don’t do it!).

I’m a botanist by education, but now that I’ve shifted careers to teach more general subjects, I’ve had to break out of my silo and learn about other taxa besides plants. This especially applies to birds (because they’re so charismatic for my students), pollinating insects, and stream indicators. I love the community aspect of iNat, because I can help others with the plants, while I’m helped with the birds and bugs.
Furthermore, I know that you can log casual observations on eBird, but for the most part, I don’t often go out for a bird walk, I go for a plant walk and it will be single species of birds I note, and iNat works better for that.
Finally, yes in general, I’m finding myself trying to log everything I encounter (mushrooms, mites, slime molds) even though I would not have had a search image for them before.
Thanks for creating the app and service, it’s been a huge boon.

I never would have taken a second look at a tiny fly that sneaked into the house, but now I do. Zooming in for a photo helps me see things I couldn’t with my poor eyesight (cool, iridescent!), and then I learn more about the category if not the species- even just from the AI if no one comes along to id. Thanks to iNat I’ve at least become an aspiring generalist if not PSLer (yet).


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