A number of major changes have been introduced in "Pokemon Go," particularly involving the types of Pokemon that spawn at nests, the location of the nests, as well as increased spawn rates. Beginning Sept. 26, 2016, "Pokemon Go" nests were altered around the world, with some completely gone. The spawn rates were reportedly also altered recently.
The BitBag stated that according to many "Pokemon Go" trainers, spawn rates have increased in heavily populated areas. There are speculations that Niantic Labs is using new information from cellular phones to spawn more Pokemon in selected locations to adequately cater to "Pokemon Go" players. Also, the game creator seems to have provided more opportunities for players in rural areas to find and catch Pokemon. Some players also reported that a number of nests have been removed, while others said that they did not notice the changes.
Heavy reported that there was a huge migration of about 50 Pokemon to various spawn points. There was no significant changes in "Pokemon Go" as far as rarity is concerned. For example, Ghastly currently appears in Bellsprout nests, Shellder appears in Diglett nests and Vulpix is spawned by former Drowzee nests. Squirtle comes out of Electabuzz nests, Charmander is spawned by former Jynx nests, and Scyther and Nidoran (male) come out of Pikachu nests. Some "Pokemon Go" players stated that there is an overall boost in activity particularly when using cellular data.
According to some "Pokemon Go" players, the big changes in spawn rates and nests happened in places like Central Park in New York City. Some nests stayed the same, while others already feature the evolved form of the same Pokemon. For example, some Charmander nests were now capable of spawning Charizard.
The changes in "Pokemon Go" will particularly be beneficial to those residing in rural areas. It is still unclear whether the new cellular phone data is taken from the actual device of "Pokemon Go" players. Niantic Labs has not yet officially announced the introduction of the relocated nests and spawn rate increase. They also did not provide an official list of the nest adjustments, so fans themselves came up with their own tables. More updates and details on "Pokemon Go" are expected soon.