Spearow can be found in the following areas: Routes 3, 4, 9, 10, 11, 16, 17, 18, 22, and 23, Treasure Beach, Mt. Ember, Cape Brink, Ruin Valley, Water Path, Canyon Entrance. Fearow can be found in the following areas prior to beating the Elite Four: Routes 17, 18, and 23, Treasure Beach, Kindle Road, Mt. Ember, Cape Brink.
A strong Normal/Flying attacker - but, unfortunately, that's its only use. While 60 Attack is reasonably powerful when you first get it (likewise for 90 Attack at the point when it evolves), it will be outpaced by other Pokémon later in the game - Dodrio in particular, which is basically an upgraded Fearow with 110 Attack. Still, in early-and-mid-game, it can prove very useful to your team. Its chief uses are against Grass-types and Fighting-types. Squirtle users will appreciate its advantage over the enemy starter, as well as its utility against the dreaded Grass-type gym. Even if not swapped out later on, Fearow can still prove itself useful in the late game on occasion, and is generally a better generic bird than Pidgeot.
Rival (Route 22, optional): If you have it by this point, Spearow is useful against Bulbasaur. Pidgey versus Spearow could go either way, and Charmander and Squirtle both have STAB moves by this point.
Gym #1 - Brock (Pewter City, Rock-type): NO.
Rival (Cerulean City): Spearow is likely unevolved by this point and so is in no shape to take on Hyper Fang Rattata. Pidgeotto is iffy and will require Potion support. The same goes for Charmander and Squirtle, but type advantage gives it the edge over Bulbasaur. Abra can be killed by anything that (has) moves.
Gym #2 - Misty (Cerulean City, Water-type): Dubious. Spearow/Fearow's poor Special Defense makes it risky to use against Misty's STAB Water Pulse - especially as its high Attack and mediocre defenses will result in it taking heavy damage from confusion - but it's better than nothing.
Rival (S.S. Anne): Evolved, Fearow can now hold its own against opponents. Unfortunately the starters only continue to grow stronger. Lacking a good STAB move at this point, it also has difficulty matching Raticate's Hyper Fang. On the bright side, its high speed gives it a chance of outspeeding and killing Kadabra, and it trounces Ivysaur with ease.
Gym #3 - Lt. Surge (Vermilion City, Electric-type): Why on Earth would you even DO that?
Rival (Pokémon Tower): Exeggcute or Ivysaur will fall easily, but Gyarados poses too much of a danger. The non-Grass starters will also be an uphill battle, and Pidgeotto may surpass it by this point. On the bright side, at least Growlithe isn't too much of a challenge.
Giovanni (Rocket Hideout, Ground-type): Not a chance against the Rock-types, and Kangaskhan is too durable and dishes out too much damage in return. Why are you using this Pokémon, again?
Gym #4 - Erika (Celadon City, Grass-type): Oh, yes, THIS is why. Resisting Grass and answering with Flying-type moves (including possibly Fly, depending upon when you pick up the HM), Fearow will turn her Gym into a salad bar. A clean sweep is a possibility.
Gym #5 - Koga (Fuchsia City, Poison-type): Ill-advised given the Koffing and Grimer lines' high defenses, and that Muk loves playing with Minimize. Don't use Fearow here if you can help it; these Pokémon have bulk and they're not afraid to show it.
Fighting Dojo (Saffron City, Fighting-type): Drill Peck or Fly your way through this Gym, but be careful - as a Normal/Flying type, it takes neutral damage from Fighting STAB. At least Hitmonchan's poor Special Attack makes its "coverage" moves irrelevant.
Rival (Silph Co.): Beat up the Grasses, avoid most everything else. Growlithe and Pidgeot will probably succumb to Fly, and you can probably manage Alakazam with a strong Normal move, if you don't give it enough time to use Future Sight and posthumously maul one of your team members.
Giovanni (Silph Co., Ground-type): Nidorino is a possibility, but Nidoqueen's decent Defense and strong offense is a deterrent. The comments from the previous battle still apply.
Gym #6 - Sabrina (Saffron City, Psychic-type): Use against Venomoth, but the Abra line's high Speed and Special Attack make it a poor idea to use Fearow against them. Unless you're overleveled, or maybe have a Speed-boosting nature (other than Timid), Fearow is unreliable here and will easily get itself killed.
Gym #7 - Blaine (Cinnabar Island, Fire-type): Possibly useful against weak Pokémon, but why aren't you using your Surf-user instead? And you do get a Rock-type Fossil revived on this very island...
Gym #8 - Giovanni (Viridian City, Ground-type): Comes in handy against Dugtrio, but the others are dangerous. Use against the Nidoroyalty if you must, but beware of strong physical attacks. Luckily, Fearow is immune to Earthquake, their main STAB attack, and can occasionally take advantage of that for a free switch-in.
Rival (Route 22, pre-Elite Four): See Silph Co., but with the additional caution of avoiding Rhyhorn. Alakazam is off-limits unless you're certain to outspeed now, because of Psychic, but otherwise dies quickly to Drill Peck.
Elite Four Lorelei (Indigo Plateau, Ice-type): Again, NO. The type says it all.
Elite Four Bruno (Indigo Plateau, Fighting-type): Machamp and Hitmonchan carry Rock Tomb. Hope for a Drill Peck OHKO on them. Hitmonlee can be handled without too many problems, thanks to its low Defense stat. Avoid the two Onix.
Elite Four Agatha (Indigo Plateau, Poison-type): Agatha's Pokémon may be frail, but they carry strong physical attacks. Thankfully, Fearow is immune to Ghost-type moves, meaning that Agatha’s Ghosts can do little more than put you to sleep or confuse you. Hopefully Fearow carries some strong physical moves as well; you can't have a Fearow without Drill Peck after all. Immunity to Ghost-type attacks comes in handy against her Gengars, but be careful nonetheless.
Elite Four Lance (Indigo Plateau, Dragon-type): Ill-advised. Strong physical attacks on all his Pokémon frighten off Fearow's poor bulk, and under no circumstances should the bird come into contact with Aerodactyl.
Champion Rival (Indigo Plateau): Use against his Grass Pokémon only. A Pidgeot-Fearow matchup could potentially work, but watch out for FeatherDance neutering Fearow’s offense. ExtremeSpeed and Flamethrower make Arcanine too dangerous, Gyarados’s Thrash risks a OHKO, and Alakazam’s Special Attack will probably knock Fearow from the sky. Rhydon, of course, should not even be attempted.
Post-Game: Fearow's bulk falls short WAY too much to face Mewtwo. On the upside, it still sees some use against Bruno in the League rematches.
The Spearow line has an extremely uninspiring movepool. It starts off with Peck and Growl, both of which kind of suck. It doesn't really have the bulk to set up with Leer (comes at level 7), and Fury Attack, which comes at level 13, is miserably unreliable (though, as enemy Fearows will prove, it can be excruciating if it hits all five times). Pursuit, which Spearow learns at level 19, is useful versus Psychics, but Fearow's Special Attack is poor and, by the time it comes in, enemy Psychics will begin to have enough offenses to frighten Fearow as much as it frightens them. It’s a good idea to not evolve Spearow at level 20; in fact, you should wait until level 25, which is when it gets Aerial Ace, a strong STAB attack that is vastly superior to anything else Spearow learns in the early stages of the game. Mirror Move (level 32 as a Fearow) has situational use if you want to try something original, and it's not like Fearow is suffering from too few moveslots anyway. Drill Peck is really what makes Fearow a power, but it only comes at level 40. By that time, it's past its prime anyway, and you will probably be considering other Pokémon.
As for TMs, Steel Wing may provide coverage, but you won't be sending Fearow out against Ice- or Rock-types unless you're trying to get it killed. Fly is useful, but Drill Peck is better unless you're specifically aiming to dodge your opponent's own two-turn moves. If you’re lacking a strong Normal-type to use it, Return can turn Fearow into an offensive beast; in fact, full-power STAB Return from Fearow’s base 90 Attack, combined with its good base 100 Speed, can allow Fearow to sweep Sabrina’s gym. Hyper Beam is also an option, if you’re looking for an insanely strong finishing move with an awful backlash. You’ll find the TM for Secret Power relatively early on, right before you go to meet Bill. This can provide Spearow with some much-needed power, as Peck and Fury Attack just don’t cut it at that stage.
Minimum stats are calculated with 0 EVs, IVs of 0, and a hindering nature, if applicable.
Maximum stats are calculated with 252 EVs, IVs of 31, and a helpful nature, if applicable.
Spearow Line Ratings
What Nature do I want? Adamant is far and away the best. Any Attack-lowering nature is extremely bad, and any Special Attack-lowering nature is perfectly acceptable. Even stuff like Lonely and Naughty works, since its bulk is basically nonexistent.
At what point in the game should I be evolved? Probably by the time you board the S.S. Anne. Before Misty is possible if you take her on after seeing Bill. However, you’ll probably want to wait until level 25 to evolve Spearow, as it learns Aerial Ace at that level whereas Fearow doesn’t. Otherwise, you’ll be lacking a good Flying STAB move until Fly or Drill Peck, which comes at level 40.
How good is the Spearow line in a Nuzlocke? It provides Flying STAB. That is its sole use. If you picked Squirtle, its coverage may prove useful; otherwise, stronger Pokémon will probably come to take its place. Its shining moment is against Erika, but after that it will probably only come out to mop up weak Pokémon, Grass-types, and Fighting-types (though beware of Rock-type coverage moves on the latter, as with Bruno’s Hitmonchan and Machamp). It's all right, and useful in the early-and-mid-game, but there are better Pokémon to use later on.