Ok I’ll explain a little better. I’m from the UK and have lived there all my life. I love to go out and photograph wildlife when ever I can and have recently discovered iNaturalist which I am really loving.
Now although I have been observing wildlife in my own country for a long time, I don’t consider myself an expert at all. It occurred to me when glancing through images of wildlife online that there are often pictures of the same animal or flora from different respective country’s that are to my eyes identical. For example the Coal Tit from Europe
These two are different species, albeit quite closely related - both are “tits”. In practice, you may find that people call the same species differently in different parts of the world, even in English (obviously in local languages it’s completely different most of the time). Here on iNaturalist, species are considered globally - if there are more common names, they are usually added, so that they link to the same species. You can always check the systematic (latin) name, which is unique.
Well, a new specie is not “decided” once for all: an author describes it and proposes its name in a scientific publication, then it may be accepted or rejected by the peers, depending on how clear the differences from currently accepted species are judged. This may take decades…
For proposing a new species the author of such a proposal first has to make sure that what they’re describing is not just a variation of or mutation within an established species, but does indeed signify a previously unrecognized/undescribed unique species, then has to go through the process of describing it and getting the international community of people who concern themselves with this sort of thing to agree that it is a new species. This is, as you might imagine, often a contentious process.
These two articles give a reader friendly overview of some of the issues and complications:
If you are on the website, you can click the taxonomy tab for each species, and see where they are related. Then click down from that higher level to see all the other relatives.
iNat photos, and IDs help us non-scientists to train our observation skills.
Each accepted species has what is called a scientific name which comprises 2 parts, a genus which goes first and is capitalized and an epithet which is unique in combination.
The Coal Tit has the scientific name of Periparus ater. The Black-capped Chickadee is Poecile atricapillus.
If you look at the taxonomy tab as suggested above, and open the ‘tree’ which describes its overall classification, you will see they both are in the family Paridae which means they are quite closely related, but still distinct enough to go into a different genus.
Another likely familiar UK bird the Willow Tit has the scientific name of Poecile montanus which tells you since it is in the same genus as the Chickadee it is more closely related to that bird than it is the Coal Tit.
Each species can have 1 or more ‘common names’ in use that can be identical around the world or be different in different places. For example on both sides of the Atlantic the name Herring Gull is used for a familiar gull. But what Europeans call the Common Gull is called Mew Gull in North America despite being the same species in this case Larus canus.
Those two not only distantly related, they don’t look similar at all! Like, look at every part of them and it will be different (colour, proportions), and we can’t even hear them from those images and know they perefer different habitats and behave differently (coal tit is close to kinglets and crested tit on how they forage high on conifers). =) Always check latin names to know if it’s the same species, but in UK you can find chickadees (different species from american) and see they’re nothing like Coal tit.
Welcome to the Forum! As you can see from the replies so far, it’s complicated (and I am no expert). Usually similar looking organisms on different continents are taxonomically different, which is reflected in the binomial name (Genus and species). Life being Life, however, there are always exceptions. Some moth species are found in the New and Old Worlds, either though natural movement or through introduction. The moth Noctua pronuba is found throughout the northern hemisphere. It was likely introduced to North America from Eurasia. Taxonomy is often arcane, but the fact that the two examples you give are in different Genera suggests there are significant internal differences to warrant that assessment. Now, some person may come by and re-define the genus (although birds are very well studied), but that would have to be scrutinized by others in the field. My beloved Pseudaletia unipuncta (a moth) was changed to Mythimna unipuncta, without anyone consulting ME! Within a region there may also be significant differences within a certain species, but they are considered, to date, as the same species.
So my best advice is to look at the binomial name when making decisions. Sorry if this is kind of rambling, but it’s a topic I’m still struggling to understand.
It wasn’t that long ago when our North American chickadees and titmice were lumped under the genus Parus, which is now restricted to the Old World. They are now in their own separate genera. I believe a lot of the genera in Paridae today were subgenera of Parus just 20 or more years ago. Phylogenetic studies have resulted in a lot of new genera (or resurrected old genera) being used to better define lineages of formerly lumped-together groups of species, especially between New and Old worlds. When genetic techniques allow you to see differences and groupings that you might not see by just looking at morphology, taxonomy follows by reflecting those differences.
And I agree, these two examples in the original post sure look similar.
(I am not a birder) In the photos, I see different beak lengths and different coloration; especially in the white head “scarf” and on the wings (spots) and body color. Yet, out in nature, without a close-up comparison to judge by, I’d have taken them for the same.
True, if one was quite far away it may be a little more difficult to distinguish them. I do see the other features you’re talking about, I didn’t deign to expand the details in my previous reply.
But similar enough to consider them closely related species (same genus), as they were once. Some groups that we call differentiated today and classify differently based on genetics are morphologically conservative – similar body structure, color patterns, behaviors – and that makes taxonomy tricky.
You can easily see white wing bar on coal tit even in motion far from you, also it has much shorter tail than regular tits, black throat mark much bigger than any other tit living with it, distinctive voice it uses constantly. Poecile tits on the other hand are unique too. Of course it’s a matter of experience, but all birds are like that, you can have pretty bad pics and still see who is who. https://www.inaturalist.org/observations/42155610
There are 42 common names listed. But, if two scientists from two different countries are discussing this bird, chances are they are using the scientific name.
If you want a really messy identification problem like we have here in Ohio in the U.S. look at this page. We have the black-capped chickadee ( Poecile atricapillus) and the Carolina chickadee ( Poecile carolinensis). Their ranges overlap about midway through the state going north and south. So, there are hybrids. They have two different scientific names. And, it has been found that their songs are not a clear way of identifying them as they learn each other’s songs where their ranges overlap and even where their ranges are close to the other’s.
Coal tit and black-capped chickadee are different species because:
They look, behave, and sound different (physical and behavioural characters)
Originate, genetically from different areas (Europe vs America, after these two continents became separated)
Are distinguished clearly at a DNA level.
Follow the format of species delineation elsewhere in the family, and for birds in general.
A closer comparison would be willow tit and black-capped chickadee, which look much more alike. However, they still differ in all the above points.
An even more interesting case is grey-headed chickadee and Siberian tit. These two “named” birds occur in different parts of the world (Russia/Siberia, and northwestern North America). But they are alike in song, behaviour, and genetics. Though geographically separated, it is well theorized that Russia and Alaska were connected in the past that allows the same species to be spread between both ends. So they are the same species.
