Looking for a monster

[NRSASD]

This is a standard pseudo-medieval fantasy game.

Here's the setting: there's a ruined fortress built on a coral atoll, completely covering it. It's several days out to sea and inaccessible from the water without ropes or a ladder. The whole place is a crumbling ruin and a nest for a trio of harpies and a couple wyverns. What I'm looking for is a swarm/colony of small winged creatures that can serve as the weaker, numerous threat that follows the harpies or wyverns whenever they leave to hunt.

I was thinking something bat-like maybe...? It doesn't matter what game or edition since I homebrew almost of my monsters anyways (monster manuals are "just guidelines"), just looking for inspiration.
Thanks for the help!

[Seto]

Giant bats is possible, or flying Monkeys if you feel like doing a shout-out to the Wizard of Oz, or scavenger birds of any sort (you can make them more monstrous by adding weird colors, bulging eyes and teeth). Young Arrowhawks maybe ? Or Vargouilles.

But I'd probably go with small flying (or gliding) snakes, it fits the wyvern theme.

[the_david]

It might be helpfull if you told us which game you play, and if it's D&D the edition might help too...

Harpies, as depicted in D&D, are actually more like sirens. (The original greek version of the siren, at least.) So traditionally, they would use their song to lure sailors to the reefs. Tactically, it might actually be better to let the harpies lure innocent adventurers to a nearby monster that is immune to sonic effects.
Another option is a harpy that attracts seamonsters towards ships and then stops singing so the monsters can attack the ship.

If you're using Pathfinder you can very easily add the Sorcerer or Bard template from the Monster Codex to make a harpy more dangerous.
Trailblazer has options for D&D 3.5 to do the same.

[NRSASD]

Technically the edition I play is a hybrid of 2nd and 3.5 D&D. I do like the idea of young arrowhawks, or maybe one of the weirder strains of giant bat or bird. I love flying snakes but I've got a plan for them already, so I don't want to use them just yet. Thanks for the input!

[Regitnui]

You want something small that flies around and scavenges? Seagulls.

What? A little more monstrous? A wyrmling dragon who one day intends to drive the other creatures off and claim the atoll as its own.

[Ninja_Prawn]

Why not stirges? Or even dire stirges?!

[Atarax]

Gargoyles? Imps?

[Studoku]

You want something small that flies around and scavenges? Seagulls.

What? A little more monstrous? A wyrmling dragon who one day intends to drive the other creatures off and claim the atoll as its own.

Dire Seagulls.

[Lvl 2 Expert]

Dire Seagulls.

Ahhh, I was gonna say that.

Although I also like the idea of something a little more exotic looking, seagulls are in many ways a great fit for the scenario. They live in colonies of as big as you like, they make loads of noise, they are fully capable of attacking creatures in and probably under water (if not, dire seagulls are) and especially the bigger ones can be pretty vicious, for such a common bird. I ones saw one getting ice cream by flying low over a 12 year old boy screaming and scaring the kid into raising his hands as cover and dropping the ice cream. That's pretty impressive given the size difference (these gulls are about 2 foot long and weigh 6 pounds at the most). A D&D-small (or tiny, if that's the flavor you're looking for) flying creature with a good peck attack, a decent dexterity bonus, an exaggerated version of that ice-cream kind of behavior and maybe some attack where they drop a rock or something from just outside of melee range, that'd be pretty cool. For extra flavor, make them work in pairs. One distracts while the other attacks, and when you kill one of them the other one goes absolutely mad.

[Firest Kathon]

If you have "only" non-monstrous creatures, you could use a swarm to make them more dangerous (Ravens, Stirges, Beetles, intelligent Beetles, Flies, bloodsucking Mosquitos, etc.)

[Atarax]

Attack them with a flock of seagull and they'll just run. They'll run so far away a a

[NRSASD]

Hahaha you guys have convinced me! I was intending to go with stirges, but dire seagulls are too great not to pass up. Picturing that scene from Finding Nemo now

[Lvl 2 Expert]

Let us know how it went.

[Atarax]

Let us know how it went.

Yeah. I'd be interested to hear how it turns out.

[NRSASD]

It went very well! I had a demented druid who had been thrown out of his order for being convinced that seagulls were the epitome of all lifeforms. He was very fond of wildshifting into a skua and hurling spells out of the swirling mass of seagulls. They swarmed PCs and nearly ko-ed 2 of them, also pushed one off a cliff and into the ocean. The PCs managed to overcome the birds with a few improvised molotovs and a lot of chopping. They've not quite forgiven me for this latest horror, and are a trifle suspicious whenever I mention seagulls haha. Mission accomplished! Thank you guys for all your help!

[Lvl 2 Expert]

*scribble, scribble*