Pokemon that used to be common but now are missing

Horseas, I used to see them somewhat often but now since gen 3, I havent seen even one here, and only a few in new york city, Why is this.

  1. there is an event going on where only gen III spawns, (i hope u know that)
  2. all spawns have to share spawn spots with more and more pokemon, thus becoming more rare. Even pidgyes are becoming more rare over time this way.
  3. Whenever a new wave of Gen III drops, niantic buffs their spawn rates a bit to encourage going out hunting. This of course hurts non Gen III spawns.

Kinda obvious reasons…

As more Pokémon are released the “pool” of spawns is diluted, i.e. where you had 151 possible spawns previously, you now have over 340+ possible spawns so less of those you used to see regularly will appear because they’re sharing the spawn points with 339+ other mons.
Plus as @Punica said, there is a Gen IIIspawn event currently & Niantic boost spawns for the release of new generations.

I know but None since like december and they were pretty common before

No so much real common but I used to get the odd Qwilfish in my area. Saw my first one the day before the Gen 3 only drop for about 6-7 weeks.

This only confirms what i said. In december Gen III started to drop. All previous reasons mentioned apply, thus less ‘old’ spawns.

A simple explanation.
If there are 3 spawns, during Gen 1, there will be 3 gen 1 spawns.

During gen 2, there will be an average of 1.5 gen 1 spawns.

Now in gen 3, there is an average of 1 gen 1 spawn.

The side effect of new pokemon is that all the old ones get less common.

I rarely see Horseas anymore too but that goes for a lot of the original Pokemon as well. You gotta figure that the more they add, the less likely you are to catch an original Pokemon.

I hope they’ll do ‘special weeks’ in the future. Imagine Gen 4… 5… 6… And finally 7. How would you ever find the one special Pokémon you’re looking for if there are 7 generations? Those few days ‘only gen 3 spawn’ was really nice, I wish they would do it more often.