American robin (Turdus migratorius)
The only thing American robins have in common with European robins is that they both have reddish orange breasts.
.European robin (Erithacus rubecula)
American robins are classified as “true thrushes” in the genus Turdus.
The European robins were once thought of as thrushes, but now they are classified with the Old World flycatchers.
Behaviorally, the two species aren’t exactly alike, and the American robin is much larger than the European one.
However, if European explorers had really been thinking (or thinking the way I do). The American robin is almost exactly like another species of true thrush that Europeans know very well.
I’m talking about the European blackbird.
Now I’m a North American. I was raised where the American robin was so common that you often saw them hopping around on lawns in search of worms.
A few years ago, I was in London’s hide park, and I saw a very similar bird to the American robin. Its behavior was almost identical when searching for worms. It is roughly the same size and shape. In fact, I think of a blackbird as an American robin covered in soot.
If you don’t believe me, have a look at a blackbird.
The common blackbird (Turdus merula)
Both of these species are true thrushes and are classified in the same genus. However, in the public mind, I don’t think many people think of them as similar. After all, American robins live in North America. The blackbirds are native to Eurasia and North Africa, although a few of them have been blown to the North American coast.
Further, I have a hard time telling these species apart if I am shown a picture of an albino or partially albino specimen of either species. Strangely, albinism isn’t that uncommon in either species.
This bird is a partially albino robin.
This bird is either a leucistic blackbird or a partial albino one.
I have no idea of why early explorers to North America didn’t think of the American robin as an American equivalent of the European blackbird. But then Europeans though the red deer relative of North America was an “elk.” They called the actual elk the moose. They also thought the large bison of North America was very similar to the Asian and African buffalo but ignored its similarity to its close relative the wisent. They called the pronghorn an antelope and the mountain goat a goat. The coyote was placed with the jackals when the jackals had their own genus, and the gray fox and island fox aren’t closely related to the true foxes.
These early explorers really confused us with their bizarre classifications, but it makes sense. I seriously doubt that the average English explorer would have ever seen a wisent or a Scandinavian elk. So it is easy for someone like me to sit back here and call them fools for not having all the information that we can easily access today.
Natural History 