Which sight records are reportable?
Recently I spent a few days on Java and saw a bunch of mammals, including two sightings of what I IDed as being very rare and little-know species (more on this below). Before submitting the trip reports, I discussed the sightings with a bunch of people, and one of them, also a mammalwatcher (let’s name him X), got kind of angry at me, saying that I should never make these sightings public. We got into a lengthy discussion, and since the subject is probably of interest to many people here, I’m going to repeat my arguments and add some thoughts in this post. I hope you’ll not find this text too boring (if you do, better stop reading soon because it is VERY long).
So X’s reasoning (if I understood him correctly) was that extraordinary claims require extraordinary proof, which a sighting without a photo or a specimen can’t be. And since I didn’t meet this criterion, I should keep silent about the sightings.
I was surprised by this argument because proving anything was the last thing on my mind. I wasn’t applying for a conservation grant based on these sightings or counting them towards the total of some Big Year competition. I simply wanted to get the information out because I assumed it would be of interest to people conducting research in the area; they themselves should decide if the evidence is good enough to be taken seriously. But was the evidence any good at all?
A century ago, ornithologists considered bird records valid only if they were supported by specimens. Very gradually they began to trust records with photos, and then sight records. It wasn’t because their criteria became laxer. It was because countless people spent decades developing the techniques for identifying birds without shooting them, discussed their findings, and published them. Did it make sight records of birds 100% reliable? Of course not. But it got to the point when they were reliable enough to do more good than harm when used in research.
Mammalogy is decades behind. Contrary to popular belief, it’s not because mammals are so much more difficult to ID by sight. In Europe, for example, there are very few species pairs that can’t be told apart by external appearance – a situation not that uncommon in birds, where some species can be reliably told apart only by song, or by nesting season/location, or only in certain plumages. It’s because until recently, few people even tried to ID small mammals by sight, and even fewer got good at it. There are still very few books listing useful field marks, and scientists studying and using those field marks seldom bother sharing their knowledge.
Just as with birds, it takes practice and learning, and the better you get, the more reliable are your records. But there is no objective way for other people to know how good you are (having a Ph.D vs. having 2 years of village school is not a reliable indicator, contrary to another popular belief). And once you get really good, it actually becomes difficult for others to believe you can be that good. My late father never believed that I could ID most birds in flight, even though he himself could ID in flight most butterflies of the former Soviet Union – a much more difficult task.
And the skeptics do have a point. Unless you are on an island with just one species of everything, sight records of small mammals are almost never 100% certain, particularly brief ones. Your brain’s image recognition software can play stupid jokes on you and make you make stupid mistakes.
But records with “hard evidence” aren’t always 100% certain, either. Photos and videos can distort shapes and colorations, or not show critical features, and people analyzing them make stupid mistakes, too (I made one just last month). Even museum specimens are routinely misidentified. Often the only way to be 100% certain is to get a good nuclear DNA sample, and even that would work only if there are reference data from all possible species.
So should you publish your sight record? Well, before you answer this question, there’s another one: can you? For scientific publications, the answer is usually no. At least one of your reviewers will always be an old-school mammologist who will demand a specimen. I gave up trying long ago. Last year I made an exception for one rat record from Iraq because it was the purpose of a whole trip, my friend and I saw the animal very well, and it was a species not recorded with certainty for a long time and thought possibly extinct, so I thought the sighting was important. Turned out, we didn’t have to bother: a month after our paper came out, another one was published by Iranian zoologists who obtained a specimen just a few kilometers from our site (but across the border) on the same week. Well, at least our sight record got “confirmed”.
That means that the only possible place to make your sight records public is this site or social networks. If you decide not to do it, you save yourself from criticism, but the information you possibly obtained goes to waste. If you do make it public, it might still go to waste, but it might also be picked up by someone and prove useful. Will it do more harm or good?
Personally, I don’t see much possible harm, even if you misidentified the species. Your record is unlikely to be cited in scientific literature and distort some study. Nobody is going to create a new national park in a crappy area or dole out funding to a wrong person based on a sight record (if you are thinking “wait, what about the ivory-billed woodpecker?”, remember that there were sound recordings believed by experts to be strong evidence).
But is there any good, assuming you are correct? There is some hope. Perhaps someone will read it and decide to check out your site when he happens to be working in the area. Or someone will keep the probability of encountering the species in mind when doing a survey. Or simply get another sight record in the same place, but get more credibility because two independent records are better than one (well, this sometimes backfires, and chains of wrong IDs are created, but such situations are rare).
Let’s talk about my two records that started this.
1. A large freetail bat flying over a river is seen at dusk, silhouetted against the sky; the only ID feature I can see is long ears protruding over the nose. I come back on another evening, see it again (but not so well) and get a detector recording (click on the green image in this post to see part of the sonogram). I can’t even attempt to get a photo because my camera broke down earlier.
Now, there are four species of freetails known from the area; three of them have short ears (and two of those three species are not large). My recording doesn’t match any of these three species, but freetail vocalizations are notoriously variable so it doesn’t mean much; besides, the quality of the recording sucks because the bat was flying a bit high and I had a tiny handheld detector. The fourth species has huge ears, it is also the only one known to roost in trees, and there are no caves or houses nearby. (That is not terribly meaningful, either, because freetails are fast flyers and some are long-distance foragers, but I saw it at dusk so it’s likely that the roost wasn’t too far.) That fourth species is known only from two records, one of them made many decades ago. There are no call recordings; calls of a related species look a bit like the one I obtained but not identical. So if I saw it, it’s an extraordinary claim, and I certainly don’t have an extraordinary proof – I don’t have any proof! And I myself have no way of knowing if I really saw what I thought I saw: what if my brain played a trick on me, or the bat had a large moth in its mouth that made its silhouette look long-eared? Why bother making this record public?
Well, first of all, the claim is not as extraordinary as it seems. Most freetails are high-altitude foragers, so they can be extremely difficult to catch unless you find a roost or happen to be mistnetting in a place where they come to drink (but large species tend to drink from larger bodies of water where it’s difficult to set up a mistnet). So a lot of species, particularly tree-roosting ones, are almost never collected and are generally poorly known; it doesn’t mean they are truly rare.
Second, if I somehow make this record public, the only harm is to me: a lot of people will tell me that I made it up. But maybe (a big maybe) local zoologists who perhaps all but forgot about this bat will now keep in mind that it might occur in the area where I reported it, and that will increase the chances of them noticing/recognizing it when they see it. I decided to make it public. What would you do?
2. My friend and I are walking along a forest trail just 5 min from a busy campground, and a rat runs across the trail along a hanging branch. I’ve been training myself to ID rodents running across roads and trails for a long time, so the first thing I look at is the tail to body length ratio; my friend is relatively new to this so he doesn’t pay attention to the tail. The tail is very long and it isn’t black. There is only one rat-sized rodent on Java with such a tail. It is known only from the type series collected decades ago, at locations not far from our trail. One of these sites was in bamboo so the rat is believed to be a bamboo specialist. The whole area is just outside Jakarta and a lot of zoologists have done research there. Of course, there is a chance that my brain played a trick on me, or that the rat had an abnormally long tail (it does happen, although much, much less often than abnormally short tails – I’ve only seen one such rodent in my life, and I’ve handled and measured thousands), or that I’m not as good at estimating relative tail length as I think. Again, an extraordinary claim without any proof?
And again, it’s not actually that extraordinary. Arboreal rodents are difficult to trap and thus relatively poorly known. It was always believed that Sri Lanka had none, but a few years ago a tree mouse was photographed there by a mammalwatching tour group, and it was from a genus known only from very far away; if not for the photo, it would probably remain unknown. I don’t think many people capable of IDing rodents on sight have been spotlighting on that trail – perhaps nobody, because there is much more pristine habitat a short walk away. And I’m almost sure nobody searched the trail for that particular species, because there’s very little bamboo there.
So should I make this record public? Again, I would be risking my credibility. Again, there is a chance that somebody will try looking for the rat along that trail, and a much smaller chance that a specimen will be obtained. I thought about this and decided not to publish the record – although I’ll not keep it a secret, I am a scientist and shouldn’t withhold information (yes, I know, a murky line). I’ll just try to carve out a week at some point and spend it living at that campground. If you’d like to try yourself, ask me for details personally.
Note: of course, everything I said only works if you are not into competitive mammalwatching. Once it becomes a competition, there should be strict pre-agreed criteria on what is countable and what isn’t. No idea what they should be (requiring photo evidence would turn the whole thing into a camera quality competition). But I’ve never been into competitive twitching, Big Days etc., so I don’t think I should discuss that subject.
Comments very welcome.