I found a guide to the Bronx Zoo from 1915 that details the animals in the zoo's collection and has some good photos as well as detailed maps of the zoo's grounds from that time. Popular Official Guide to The New York Zoological Park, by William T. Hornaday: a Project Gutenberg eBook
I think @Ituri owns this one, or at least I recognize from the cover as a year I've read. One funny thing I've noticed when it comes to old Bronx guides is they had a habit of more or less just copy and pasting the same exact guide every single year with the only changes being to the few areas/species that had changed from edition to edition. I've also noticed that they like to talk about animal groups in general along with the species they keep and sometimes don't always make it clear which taxa are actually at the zoo and which they're just talking about in general. All else aside, it's nice to see this uploaded to the internet! ~Thylo
What Hornady says about animal welfare and wildlife conservation show that this man was several years ahead of this time.
Interesting read! European Bison described in the guide, just 12 years later will become extinct in the wild. They care of well-being of individual animals, like elephants or orangutans. They advocate protecting Indian rhinos from hunting, which were then extremely endangered. However the rarity of animals is usually mentioned only in the context that a given species is difficult to purchase. There is no much interest in breeding wild animals, and the idea that zoos could save animals through captive breeding is still unknown. Wolves are still described as a vermin threatening more valuable hoofed animals. Great apes are described with affection. However they apparently usually died soon and were continuously replaced by new ones, judging from the text that the zoo rarely has not a chimp nor an orangutan on display. Howler monkeys are considered impossible to keep. A gorilla has never reached Bronx. However the great heron aviary is completely modern, and remains the biggest aviary in Bronx Zoo in 2020.
The Aitken's SeaBird Aviary is not the same aviary that existed on zoo grounds back in 1915. The original aviary collapsed in a snowstorm in 1995, releasing dozens of terns and gulls of many different species into the New York wilds which were never seen again. The current aviary opened in May of 1997 in its place. ~Thylo