Dose anyone have idea about why ClassID and Species are different?

I find ClassID and Species are different so I wonder how the ClassID come and is there any connection with Species?

We’re using eBird species codes as class ID for the final submission format. If you take a look at the validation data, you’ll find a text file wich contains the mapping from species name (as in the training data) and ID code (as in the validation and test data). You can also find the species codes in the metadata for each audio file. There should be a field named “ebird code” in each json file. Let me know if there are any issues with labels, species and codes in the dataset - I’ll fix it asap.