I've tried so many times to learn what the "rule" is for capitalizing animal names or not and there are so many different takes on the matter, and then they flip flop which is "correct." It seems different branches of life sciences also use different rules, so what goes for plants doesn't always go for animals, and then language people throw in their own 2 cents as well.
Here's a quick article that shows some groups' opinions on the matter. If you're a language/grammar nerd, give it a peak.
One example from the article is if you see it written: "I saw a yellow warbler." Does that mean you saw an unknown species of warbler that was yellow, or did you see the species "yellow warbler?" If it was written as "I saw a Yellow Warbler" vs "I saw a yellow Warbler" it would be clear, but that is not how many groups say you should write it.