Learning to “bird” (i.e., spot birds and determine what species they are) is no easy matter. There are guides that have color-coded pages so you can begin by looking for birds that are primarily of the color of the one at which you happen to be looking, but then the females and males can differ greatly and the young can look very different from their parents, too.
If you can learn something about “families”, that will help you narrow down your search in other guides. So I began associating the family of thrushes with birds that have spotted breasts. I discovered that is true for some of the avian species that have the word thrush in their name, like the hermit thrush (Catharus guttatus) with its reddish tail and the wood thrush (Hylocichla mustelina, below right) with a really beautiful song.
Wikipedia says that a characteristic of this bird family is that most species are of a gray or brown color, often with speckled under parts. But you can’t count on that being a definitive trait. For example, the large brown thrasher (Toxostoma rufum, below left) is not in the thrush family but its speckles and streaks are more than obvious. And the lovely little ovenbird (Seiurus aurocapilla, below right) with an orange stripe on its head looks similar to the hermit thrush but is actually a member of the warbler family.
You can’t count on the name to help out either. The Louisiana waterthrush (Parkesia motacilla) is not a thrush at all but a somewhat larger warbler species that places its nest near water.
On the other hand, I was surprised to find out that American robins (Turdus migratorius) are thrushes. But then I saw that the young robins do have speckled breasts – very obvious on this one to the left.
And I learned that Eastern bluebirds (Sialia sialis) are a thrush species, too – those spots are also evident in the young!
It turns out that Eurasian (common) blackbirds (Turdus merula) are thrushes, too. The males, like this one seen in Switzerland, are all black but the females show some spotting.
Nevertheless, speckling and spotting are no clear-cut clues to thrushes and common names can be confusing and deceiving. Perhaps I should give up on examining bird breasts to help figure out what species they are. Enjoying the birds, their behavior and their appearance is a much better birding experience for me than aiming to become an identification or birding expert!