As of yesterday, Moltres is no longer available in Pokémon Go. Instead, the Electrifying Zapdos has started spawning in gym raids across the globe. Given that Zapdos will only be around until August 21st-ish, here are some tips for defeating and capturing one if you are lucky enough to spot a raid.
First up, while the raid has a recommended team size of 20 players, experimentation this morning has suggested groups of as few as eight can take down the behemoth with plenty of time to spare. A Zapdos raid has already been beaten with a team of just three maxed out players in Japan, so group size mainly comes down to how well prepared your players are. As always, local Pokémon Go Raid Facebook groups seem to be the easiest way to organise a team for a particular raid instance.
Regarding team selection, you're going to want as many Rock/Ground Pokémon as possible in your party. As with all previous legendaries, Golem should be the highest priority addition to your team, as Rock Throw and Stone Edge deal massive damage and the Pokemon's high defence stat keeps those moves in play as long as possible.
Tyrannitar is still a little tougher to get a hold of than Golem, but its very high HP and ability to learn Stone Edge gives it a similar ability to stay in the fight longer while dealing high damage.
Rhydon also lines up well with the type matchups, and has a high attack stat, but doesn't shine quite as spectacularly as Golem or Tyranitar.
Failing these, Ice and Dragon type Pokémon seem to fare well against Zapdos and can help fill out a full raid team.
When it comes to catching a defeated Zapdos, it's worth noting that Zapdos tend to spawn fairly close to the player, making curve balls easier to land hits with, but it also moves around much more erratically than previous legendaries. Its movement pattern most closely resembles that of Magnemite, so it may be worth watching Magnemite movement footage online to get an idea of how best to use your Premier Balls.
Good luck, and happy legendary hunting.