Skyfall has five bird types, and none of them spawn with equal probability. Every bird carries a spawn weight alongside its points and speed, and those weights are what actually shape how a round feels far more than any single point value does.
Crows carry over half the total spawn weight in the game — they're slow, worth a modest 10 points, and they're the baseline the whole round is built around. Red swifts are meaningfully rarer and faster, worth double a crow at 20 points. Golden birds are rarer still and worth 40, moving at nearly double a crow's top speed. The avoid-dove sits at a similarly low weight to golden birds, and the Phantom — the fastest, highest-value, and only erratically-moving bird in the game — is rarer again and doesn't enter the spawn pool at all until wave 3.
That distribution is deliberate: a round where golden birds and swifts were as common as crows would inflate scores far faster than the wave and combo systems were tuned around, and it would erase the "high-value target, are you willing to go for it" tension that makes a golden bird worth noticing in the first place. Keeping crows dominant means the average moment-to-moment decision is simple, and the interesting decisions — chase the fast swift, commit to the rare golden bird, track the dove so you don't tap it by mistake — stay genuinely occasional rather than constant.
The pale dove is the only bird in the game worth negative points, and it's built to look and move differently enough from the other birds that a player who's paying attention can tell it apart before their finger moves. Its entire purpose is to force a half-second of active reading into what would otherwise be pure reflex — you're not just tapping everything that crosses the screen, you're checking first.
The Phantom bird is the dove's opposite number: it's the only erratic mover in the roster, meaning its path isn't the same smooth arc every other bird flies, and it's gated to wave 3 onward specifically so it's introduced only after players have had two full waves to get comfortable reading everything else first. It's also the single highest point value on the board outside a boss kill, at 60 points, which is what makes tracking an erratic target under wave-3 spawn pressure feel worth the risk instead of just an annoyance.