It totally depends on the species! Adult male black-headed grosbeaks look bolder, with a rusty orange body and black head, while females or immature birds are brown and tan like the bird in the OP.
If it was something like a crow where both sexes look similar there’s not really a way to tell, short of doing a genetic test.
Out of curiosity, how can you tell the sex from the image? I thought birds were legendarily difficult to sex even if you’re holding them in your hand
It totally depends on the species! Adult male black-headed grosbeaks look bolder, with a rusty orange body and black head, while females or immature birds are brown and tan like the bird in the OP.
If it was something like a crow where both sexes look similar there’s not really a way to tell, short of doing a genetic test.