One of the first things I do on iNaturalist when doing any sort of ID that I feel less than fully sure about, is to use the “Similar Species” feature on the iNat page for that species or taxon. I select a broad region (like northeast or mid-atlantic or something of the sort) so that I get a big enough sample size, but one tailored to the specific region, not worldwide because that often has too much noise. A then go through the entire list and make sure I know how to distinguish between the taxon I’m wanting to ID something as, and other potentially-confused taxa. If I can’t do this confidently, then I usually refrain from making the more specific ID and instead go with the more general ID.
I also ask for help a lot. I try to reach out to and get to know some of the more experienced users. For example, lately I’ve been trying to get better at birch (Betula sp.) identification, which I find devilishly hard. There are a few really knowledgeable users, and I’ve called them in a couple times, and I also have commented on various observations, asking them how they made certain ID’s. I use the “top identifiers” leaderboard to locate people who have identified a lot, and I check their ID’s and if they’re still active on the site, which they usually are, I ask them questions or for clarification. These “power users” have been incredibly helpful to me over and over again.
When I’m trying to learn a new taxon, when I start to feel confident, I like starting by going through “research grade” observations. I don’t want to mess around with the uncertain ones that just have a single ID and need more ID’s. I only move onto these when I feel even greater confidence.
I think a lot about range and habitat when doing ID’s. I notice that a lot of things might look plausible for an ID (and might be suggested by the AI) but are clearly out of range and/or in the wrong habitat. Knowing even a little bit about range and habitat, or even knowing nothing at all but merely knowing to check at all, and checking briefly before making an ID you are uncertain of, can go a long way. You can usually find a little about range and habitat for most species with a brief google search.
I also use iNaturalist to look at range. I check to see if a record is out of place. For example, if I see someone else’s ID, or am tempted to make my own ID, as a particular taxon, but I see it is a single, isolated point, then I start researching more. Basically, if something seems unusual or out of range, I demand greater rigor in ID. Part of this is because it’s a clue that the ID might be wrong, and part of this is because the implications for science and for the integrity of the data, if the ID is wrong, are greater. If you mis-ID a common species in the heart of its range, in the proper habitat, there is not going to be a lot of damage done. Yes, it’s not ideal, but it’s not going to change tracking of that species’ range or abundance very much. However, mis-IDing something at the edge of its range or somewhere where that species is rare, is more problematic for data integrity.
I know you don’t want to get too taxon-specific, but…I mostly ID plants and for them, whenever I have any range questions I consult BONAP. I’ve found it to be the most reliable source for range maps, more accurate than the USDA PLANTS database in many cases.
For plants, I also don’t just stop at ranges of wild plants: I also consider whether plants are widely used in landscaping. If it’s a plant I don’t know, usually a basic web search can turn up whether or not it’s sold or stocked at commercial nurseries, which is a strong clue about its use in landscaping. You can also use iNaturalist itself to determine which species are widely used in landscaping. Many species are common in landscaping outside their native range; for example, I see Eastern White Pine (Pinus strobus) planted in the coastal plain, southeast from its native range, frequently, and I also see it planted southwest of its native range in the midwest, such as in parts of IN, IL, or OH where it would not naturally occur. And red pine (Pinus resinosa) is sometimes planted in plantations outside its native range, but rarely planted in landscaping. Knowing these things is useful for ID…you can usually tell if something is in or near landscaping, or in or near a plantation, from an aerial photo.
If the location is obscured and I can’t use the aerial photo to discern much about habitat, and the habitat isn’t super clear from the photo, I’m more reluctant to make ID’s in cases where I feel uncertain.
For birds, I use eBird; they have curated range and frequency maps which far exceed what you can do with iNaturalist. I look up their bar charts, usually for a county or a set of several counties in a region in or around where the ID in question is. I use this to narrow down species to check against, and then exhaustively check these species in field guides. I make sure to look at the specific time of year, which eBird breaks roughly into 4 weeks per month. Some species might be common the first week of may but rare the fourth week, in a particular area, so making sure to look at the exact right time in the chart is critically important.
I also try to keep a skeptical mind. I try really hard, but I am still wrong frequently. I can spend hours in the field looking at stuff and reading books and going back and forth, and still make a lot of mistakes when I am trying to ID stuff based on photos.
And I continually remind myself that species are a social construct. Taxa are always changing and being reclassified, and many can hybridize. If I’m getting confused, I look up the potential for species to hybridize…in some cases, hybrids are predictable, but in other cases, like with birches and oaks, there can be almost a continuous cline of intergrades between certain species, and I try to remember this when making ID’s and say “This might be a hybrid or intergrade and I don’t really know.” in the cases when things conflict.