50 with all uniques seems extremely swingy and hard to balance, Black Market at least makes you pay for the card. Why do the Birds scale? It would make more sense to have a static number, similar to black market, and maybe even just have 20 or 30 and use all of them every time. The concept is interesting, though. It feels like a promo.
Albatross doesn't need a dividing line, those are for effects unrelated to playing the card.
Bluejay can probably be a regular peddler, as that's a $4.5 effect and that's the price point most of these seem balanced at.
Bluebird is good, the reaction seems like it could be a card.
Catbird should have a pricing and/or type restriction.
Chickadee seems fine, although weak, since it only loses them a card or gives them one piece of junk.
With Crane the reaction is odd, but interesting, and the on play is good. Maybe too weak on the reaction side?
Dove is really good at shutting down attacks, it might make them non-viable or be centralizing.
Eagle is good.
Why does Falcon curse you? Self junkers are unpopular if they don't give you a way to deal with the junk, like Death Cart.
Finch is quite interesting.
Flamingo needs a dividing line.
Goose is pretty interesting as an attack.
Grackle is odd if it hits a good card, then it's bad. Can be political if you hit a victory card.
Grosbeak is very interesting.
Heron has no tracking.
Hummingbird is fairly good as a concept.
Ibis might be too important, cantrip cursing is really that good.
Junco is good.
Kingbird is definitely very underpowered, and is usually worse than great hall, because you're self-junking.
Lark is usually a Lab.
Loon is conceptually sound, but needs to be rephrased to match Crown.
Why does lyrebird reveal two but only take one?
Macaw has strange phrasing, it doesn't need to say distinct.
Mockingbird does need to be a command, plus it's often a Superlab, which is an issue, if any moat variant is the cheapest, it's a superlab.
Nightingale needs to be slightly rephrased to match Werewolf because of things like Scepter and some Menagrie events that play the card in the buy phase.
Nuthatch is quite interesting.
Oriole is too easy to activate.
Ostrich is unclear, does each player include yourself? It doesn't say each other player.
Owl needs a similar rephrase to Nightingale, cantrip boons were cut from Nocturne because of slowness.
Penguin is pretty interesting, but there are non +Card ways to draw, i.e. Scrying Pool and Envoy.
Puffin is a bit weak? It's pretty much worse than Owl.
Quail is fine.
Raven can hit Provinces, it needs a cost range.
Rhea is quite weak, especially if you can't trash it. Maybe make it a Market.
Extra turns are very strong, and the fact that birds are uniques makes Roadrunner very swingy.
Robin is pretty cool.
Shrike doesn't seem very cohesive.
Sparrow is quite weak in comparison to the many similar cards.
Starling is simple, but nice.
Stork is a bit of an odd bird (ha) but I like it.
Swallow is underpowered in comparison to Advisor, which is at the same price point.
Swan shouldn't hit victories.
Tanager might not play well? It forces you to have a dead card to gain it.
Titmouse, like Nuthatch, is nice.
Vireo needs a rephrase like Crown the dividing line is uneeded.
Vulture needs a way to put cards in the trash.
Warbler is interesting, but weak.
Woodpecker is a bit weak.
Wren is extremely interesting.
The Baby Chick line is interesting, but the power of the final stage and the fact that only one person has access to it is very swingy.
