One of the first birds that confused my brothers and I when we started birding in the early 1970s was the female red-winged blackbird. We were all wedged into the maroon Buick Skylark to go "birdwatching" together after my brother came home from college having taken an ornithology course.
We had the radio on the first few miles listening to "Where did our love go" by the Supremes https://www.youtube.com/watch?v=qTBmgAOO0Nw when someone looked out the window at a streaky brown bird perched on a bridge abutment. We passed our Sears 10 x 50 binoculars around in succession while leafing through my first copy of Peterson's Field Guide to the Birds, given to me by my Aunt Carol when I was five, and finally we figured out what this 'mysterious' bird really was. That' s how all birders start in this world. We learn the common birds and form a baseline knowledge of what we expect to find. Then we can separate female blackbirds from sparrows (that sharp beak tells all) and learn what habitats we expect to find them in. The Art of Birding is a cumulative process. Enjoy every step!