Having been born with smaller but sharper beaks the Birdlin gains a 1d4+ Str mod natural weapon

  A Birdlin can slow descent vertically up to 60 ft; to heights up to 120 ft, or to glide horizontally 30 ft, an Athletics check can be made at the DM's discretion
(Note you cannot glide in medium and heavy armor)

 Due to fragile bird-like bones, these creatures aren't as durable as their goblin ancestry. This does however allow them to glide but not fully fly with relative ease from the right height

Birdlins reach adulthood at age 8-12 and live up to 60 years.

Birdlins are typically neutral evil, as they care only for their own needs. A few goblins might tend toward good or neutrality, but only rarely.

Birdlins are between 3 and 4 feet tall and weigh between 40 and 80 pounds. Your size is Small.

Your base walking speed is 30 feet.

You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can’t discern color in darkness, only shades of gray.

When you damage a creature with an attack or a spell and the creature’s size is larger than yours, you can cause the attack or spell to deal extra damage to the creature. The extra damage equals your level. Once you use this trait, you can’t use it again until you finish a short or long rest.

You can take the Disengage or Hide action as a bonus action on each of your turns.

You can speak, read, and write Common,Goblin, and Auran.