At its core, iNaturalist is about making observations and identifications. Anyone who can get outside and point a camera can make observations. But identifying observations does require some expertise
Learning to identify organisms is a lifelong journey of slowly becoming better acquainted with more and more critters. Think of it like learning to recognize people in your neighborhood. We wouldn't expect you to know everyone's name, but there's no excuse for not knowing anyone!
So don't feel bad if you can't identify as many observations as well as you'd like, the important thing is to remember that everyone can and should get started learning how to identify organisms! Here are three different strategies that you can pursue in concert:
Generally, the cast of critters observed on iNaturalist varies depending on where you are in the world. But if you had to pick species that are likely to turn up nearly anywhere in the world, the group to bet on would be species that are closely associated with humans. These five species have been deliberately brought around the world by humans and become established (e.g. breeding on their own) in nearly every urban area around the world and are relatively easy to distinguish. Learn them and you can help confirm the identification of many observations posted each day on iNaturalist.
These relatively large lady beetles have been spread around the world as biological pest control (lady beetles prey on aphids and other insects that eat plants). Most can be readily identified by the black 'W' on the white shield (called a pronotum) behind the head. Note that the white triangles that make up the 'W' are sometimes filled with black. While the abdomen of these lady beetles usually has the familiar 'red with black spots' lady beetle pattern, some don't have spots and there is a dark form with red spots on a black background. Also remember that lady beetle larvae and pupae look quite different. So if an observation doesn't match the adults described here that doesn't necessarily mean it's not an Asian Lady Beetle.
First review these Research Quality observations that we're fairly confident are indeed Asian Lady Beetles to get a sense for how to recognize them. Now see if you can help confirm that these observations are Asian Lady Beetles by adding your own identifications.
House Sparrows became accustomed to people within Europe during the days of the horse and buggy by eating leftover grains fed to livestock. They've since spread around the world with humans and continue to do well in urban environments. If you're in a city and see a little bird hopping around by your feet, chances are good it's a house sparrow. The females and juveniles are relatively drab and harder to identify, but adult males are unmistakable with their black bibs, gray bellies, and chestnut backs. The similar Eurasian Tree Sparrow has also followed humans around the world but is less ubiquitous than the House Sparrow and males lack the gray cap and have black spots on their cheeks. In parts of Europe and Africa there are other similar Passer sparrows, but in much of the world like the Americas there aren't any close relatives to cause confusion.
Red-eared Sliders are common pets, and as a result have been released into ponds around the world. These turtles are actually a subspecies of Pond Sliders (Trachemys scripta). The red 'ears' behind their eyes makes them unmistakable. Beware that on muddy or old turtles the red marking is sometimes not visible or very dark, so if your turtle lacks these markings it could still be a Red-eared Slider. But if it has them, there's nothing else it could be.
The Honey Bee is native to Europe but was transported around the world in bee hives for pollination and honey. Their furry thoraxes and amber abdomens with dark stripes are characteristic. Contrast with bumble bees which are generally larger, hairier and black and yellow colored, and with hornets and wasps which generally are not hairy. Some people confuse hover files with honey bees but these only have one rather than two pairs of wings and short bristly antennae.
Rock Pigeons are native to Europe and nest in cliffs. They are the ancestors of domestic pigeons, which like dogs have been bred into all sorts of different shapes and colors. Escaped birds adapted well to nesting in cities and now these 'city pigeons' can be found around the world. Most have the look of the ancestral Rock Pigeon which includes light gray wings with black bars and a metallic sheen on the back of the neck. But it's not unusual to see pigeons of many different colors mixed together in groups. Many species of Turtle Dove have become established in urban areas, but they generally have solid gray wings and often a dark bar across the back of their neck.
One great way to start becoming a better identifier is to start familiarizing yourself with coarse groupings. For example, there are literally thousands of species of Arachnids (Class Arachnida) and no one person can identify all of these species. But there are just a handful of Orders in this Class. And many of them, like Spiders and Scorpions you're probably already familiar with. If you can learn how to distinguish these coarse groupings you can improve the identification of thousands of observations from around the world on iNaturalist.
Start by filtering all observations of Arachnids where the finest rank is Class. This set of observations all have Main Identifications of the Class Arachnids. Pick one with a clear photo. Our goal will be to add an identification of a finer rank of Order towards improving the Main Identification.
Now follow this key to the Orders of Arachnids. Odds are you picked a Spider (Order Araneae), but you never know. This key will teach you to rule out other Orders like Scorpions. You'll be able to confidently add an identification improving the identification from Class to Order and you'll be able to defend your identification if anyone asks.
Body divided into 2 main body parts: 'butt' (abdomen) and 'head' (cephalothorax). Legs attaching to head.
go to Spiders (Order Aranae)
Body not divided into 2 main body parts
Familiar and diverse with Global distribution. Small to large. Some spin webs. Very commonly observed.
Ticks are hard bodied and parasitic on vertebrates. Mites are soft bodied and are parasitic or free living. Very small to small. Global distribution. Commonly observed.
Tail ends in stinger
No stinger at end of whiplike tail
Venemous hookshaped 'stinger' on tip of tail unmistakable. Found on all major land masses except Antarctica. Small to large. Greatest abundance/diversity in tropics and deserts, but some species found naturally or introduced to most parts of the world. Commonly observed.
Tropical and subtropical areas excluding Europe and Australia. Medium to large 25 to 85 mm. Sometimes considered Order Thelyphonida. Uncommonly observed.
Pinchers (pedipalps) crab-like with "thumbs"
Pinchers (pedipalps) grasping but not crab-like and without "thumbs"
Very small (2 to 8 millimetres). Pinchers (pedipalps) generally crablike consisting of an immobile "hand" and movable "thumb". Global distribution. Uncommonly observed.
Tropical and subtropical regions worldwide. medium to very large 5 to 70 centimeters. Raptorial pinchers (pedipalps) modified for grabbing and retaining prey but not crablike and lacking movable "thumb". Uncommonly observed.
Abdomen ends in tail. Very small (less than 5 millimeters). Dark, damp places.
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No tail. Very small to large.
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Tail longer than abdomen
Tail shorter than abdomen
Tropical and subtropical soils worldwide. Very small (less than 3 millimeters). Damp, dark places. Rarely observed.
Mostly tropical (but ranging into California and Arizona). Very small (less than 5 millimetres). Seek water and avoid light. Cave or soil dwellers. Rarely observed.
Thin, stilt-like legs. Global distribution.
Legs not stilt-like. Tropics or arid places only.
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Global distribution. Commonly observed.
Conspicuous jaws (chelicerae). Small to large. Arid places worldwide.
Jaws (chelicerae) not conspicuous. Very small. Tropics only.
All warm deserts and scrublands in all continents except Antarctica and Australia. Small to large (reaching 12–15 cm). Uncommonly observed.
Afro and Neotropics only. Small (5 to 10 millimeters). Tick-like shape. Rarely observed.
Learning to identify species is much more manageable if you focus on the species in your backyard. There are about 7,000 species of amphibians globally, but in your neighborhood, there are probably more like 10. Developing local expertise is what being a naturalist is all about. Nobody is in a better position to become an expert on the plants and animals in your backyard than you.
You can use the Observations page on iNaturalist to learn more about the species from your backyard. Start by clicking on 'Observations' in the top menu to navigate to the Observations page.
Assuming there are observations matching your filters, click the 'Species' tab to see the species that these observations represent. In San Francisco County, there are just three species of Swallowtail Butterfly. You can click on them to browse the observations themselves. Study the species and see if you can recognize ways to distinguish them. For example, Western Tiger Swallowtail has thin tiger-like black stripes that run perpendicular to the wings. Anise Swallow tail has thick black shoulders running parallel to the wings.
Next, try navigating back to the map view and choose a coarser encompassing place such as the state of California. In California 11 species of Swallowtails have been observed. This may give you a sense for species that might turn up in your backyard that haven't been observed there yet.
You can learn from members of the community that have identified or observed these species by commenting on the observations or messaging them directly. There's no better way of learning how to identify a species than asking someone who knows.
And nothing beats seeing species in the flesh so get outside and try to find and observe these species on your own.