For two birds that are surprisingly far apart on the family tree, American crows (Corvus brachyrhynchos) and common ravens (Corvus corax) can be awfully hard to distinguish, especially if you rarely see both together. But with the right tools and a little practice you can most certainly develop the skill. https://corvidresearch.blog/2020/04/16/the-definitive-guide-for-distinguishing-american-crows-common-ravens/