Answer:
Size/Looks/Speed
Step-by-step explanation:
Hummingbirds are the smallest type of bird, while cardinals are genuinely a size of a pigeon. Hummingbirds are usually bright in colors (often green/blue/red) while cardinals are red. Also, hummingbirds are very fast and usually flap their wings 10-15 times a second, but they can fly up to 49 mph. Cardinals don't really even flap, they move their wings in a figure of 8. But they can "flap" up to 80 times per second.
Hope this helped you out! :)