I don't have time anymore. I am average 40+ hours at work. It's also proof that it took me this long to reply, but I don't come here often. I just don't have time anymore. I'm just now even seeing this.
How come many pages are blank? Because there are [almost 11,000] species of birds. Many are very rare and/or new, in this case, there might not be much info.
How come this [insert page name here] has no info? As I've said before, there are [almost 11,000] species of birds and many of them are very rare and some are new, in which case they might not be in some of the older guides.
From Taxonomy in Flux: As of May 28, 2018, the TiF list contains 10928 species in 2406 genera, 251 families, and 46 orders.