-Spearow - Mid Tier
-Availability: Spearow can be caught at Route 22 at levels 3 through 5 in Red and Blue and at levels 2 through 6 in Yellow. However, finding them could potentially be time-consuming, as it has a one-in-ten chance of appearing. As for evolving, Spearow evolve at the fairly average level of 20.
-Stats: Spearow and Fearow are fast and have a solid Attack stat, but they're both frail. Also, their Attack tends to fade into the "average" range as the game reaches its climax.
-Movepool: Spearow's movepool isn't exactly vast; the only moves it can learn, with the exception of Agility, which is rather useless due to Spearows high Speed, are either Normal- or Flying-type. It gets Peck from the start, which allows it to differentiate itself from Pidgey in addition to mauling almost everything in Viridian Forest. Fury Attack, while time-consuming due to it being a multi-hit attack, is more powerful against those neutral to Peck on average. Later on, Spearow (which should be a Fearow by then) learns Drill Peck at level 34, which is after it gets access to Fly, but since the two have similar base powers and Fly is a 2-turn attack, Drill Peck is often the better choice between the two. Mirror Move, while unreliable, has its uses, and with Drill Peck and Fly being the only mandatory moves, Fearow definitely has room for it.
-Power: As mentioned above, Spearow destroys everything in Viridian Forest, barring the hard-to-find Pikachu in Red and Blue and the occasional Pidgey as well as the Nidoran trainer in the bottom left corner of the woods. While Spearow doesn't exactly do well in Mt. Moon or Rock Tunnel, the small amount of Rock-types in between allows Spearow to hold its own. After Rock Tunnel come Pokemon Tower and Celadon Gym, both of which are handily beaten by Fearow, courtesy of Fly. However, once those areas are cleared, Koffing and Weezing appear, causing Fearow's usefulness to decrease to the part of the game before Rock Tunnel but after Mt. Moon.
-Type: Normal doesn't do much for Spearow, but its secondary Flying typing allows it to crush the Bug-types that are commonplace early on in the game, but also leaves it vulnerable to the Rock-types that appear shortly afterward. Another thing to take into account is the redundant coverage Fire- and Flying-type moves have: they both hit Grass- and Bug-types super effectively, and they're both resisted by Rock-types. This means that if you chose Charmander as your starter, you probably shouldn't be using Spearow.
-Match-ups:
--Brock: Spearow isn't of much help to you in this fight, due to Peck being resisted by both of his Pokemon.
--Misty: While Spearow's attacks aren't resisted by any of her Pokemon, her Starmie outspeeds it and deals a hefty chunk of damage to it with Bubblebeam.
--Lt. Surge: Same story as Brock, but Lt. Surge actually has a move that hits Fearow super-effectively.
--Erika: While her Victreebel/Weepinbell does know Wrap, Fearow is faster and it should know Fly at that point. Also, because Erika will not attack Fearow with a move that it resists, even if it doesn't do damage in the first place, none of her Pokemon will not use Stun Spore, Sleep Powder, or Petal Dance against it, making Fearow's job much easier. In fact, if you wanted, you could possibly defeat the entire Gym with Fearow alone.
--Koga: Unfortunately for Fearow, Koga's team in Red and Blue has 3 Pokemon with respectable Defense, meaning that while it does better against him than against Brock, it doesn't exactly excell against him either. In Yellow, it's a different story, thanks to his team literally consisting of 3 Venonat and a Venomoth. Repeated Psychic-type attacks do take their toll, however.
--Sabrina: In Red and Blue, this fight is the best shot Fearow has at utilizing Mirror Move. If Mr. Mime uses Light Screen, Fearow can Mirror Move it, halving all special damage (barring Psywave). However, if Mr. Mime doesn't use Light Screen, odds are that Fearow will lose against Alakazam. In Yellow, all of Sabrina's Pokemon are a whopping level 50, and as such are faster than Fearow. When this is combined with Kadabra and Alakazam's incredible Special, it shouldn't take long to notice that Fearow doesn't do too well.
--Blaine: Honestly, this fight could go either way, but the odds are somewhat in Blaine's favor due to Rapidash's Fire Spin and Arcanine's surprisingly usable bulk.
--Giovanni: It should go without saying that Fearow shouldn't even come near his Rhyhorn or Rhydon. In Red and Blue, Dugtrio has Slash, which Fearow will gladly Mirror Move back in its face for the probable OHKO, while Dugtrio can't even touch Fearow in Yellow. Speakin of which, Yellow has Persian, who also knows Slash, which does a ton when used against it via Mirror Move. Finally, the Nidos, while easily manageable in Red and Blue, know Thunder in Yellow, causing Fearow to have second thoughts about taking them on.
--Lorelei: All of Lorelei's Pokemon either have great physical bulk, an Ice-type attack, or both. The outcome of this match is obvious.
--Bruno: His Fighting-types are soundly beaten, while his 2 Onix stand(?) tall against Fearow's assault.
--Agatha: While Fearow does impeccably in Pokemon Tower, that performance doesn't transition to the fight against Agatha, mainly due to the fact that the Ghost-types in Pokemon Tower were lower-levelled than Fearow while it's the other way around for Agatha. However, her main strategy in Red and Blue is to put her opponents to sleep or confuse them, and the former can be remedied via the Poke Flute.
--Lance: Considering Fearow's forgettable physical bulk as well as the considerable strength of most of Lance's Pokemon, it should be safe to assume that Fearow's not going to be taking any Hyper Beams from them any time soon. In Yellow, his 2 Dragonair and Dragonite know moves super effective against Fearow, meaning they might not even have to use Hyper Beam against it.
--Rival: Unfortunately for Fearow, the only notable Pokemon it can beat on a regular basis is Venusaur. Everything else either beats it or isn't impressive to beat.
-Additional Comments: Spearow is your average early-game Flying-type: it's great against the numerous Bug-types early on and is otherwise solid whenever it isn't face to face with a Rock-type, but it isn't always the best choice in a major battle, due to its poor bulk and lack of coverage outside of STAB. It also has to contend with being mediocre when being used with Pikachu and Charmander: the former due to the fact that it tends to hog the Viridian Forest exp. while being no good against Brock and the latter due to redundant type coverage. However, Spearow is still a solid Pokemon, notably one that is able to clear out Pokemon Tower without having to use Dig or a Psychic-type attack.