The thunderbird appears as an enormous raptor with blazing, electric-blue eyes. Its feathers are a mix of dark gray and snowy white, resembling the clouds of a thunderstorm. Its wings periodically shed wisps of fog and arcs of electricity that become more abundant when it is angered or excited. The thunderbird measures 30 feet from beak to tail, and its wingspan can reach 120 feet.
Automatic Language: A thunderbird can speak Auran (the language of avian creatures).
Breath Weapon (Su): Every 1d4 rounds, a thunderbird can breathe a 60-foot-long cone of sonic energy as an attack action. Any creature in the cone takes 1d10 points of sonic damage per 2 Hit Dice of the thunderbird (8d10 for the typical adult specimen). A successful Reflex save (DC 10 + 1/2 the thunderbird’s Hit Dice + its Constitution modifier) halves the damage.
Fear Aura (Su): Any creature within 60 feet of a thunderbird must succeed on a Will save (DC 10 + 1/2 the thunderbird’s Hit Dice + its Charisma modifier) or be shaken for 1d4 rounds. Whether or not the save is successful, that creature cannot be affected again by that thunderbird’s fear aura for 24 hours.
Improved Grab (Ex): To use this ability, the thunderbird must hit a single opponent at least two size categories smaller than itself with both claw attacks in the same round. If it gets a hold, it automatically deals damage for two claw attacks and a bite attack each round that the hold is maintained. Immunities (Ex): Thunderbirds are immune to electricity and sonic damage.
Thunderbird (Chick): CR 3; Medium-size magical beast; HD 5d10+5; hp 32; Mas 12; Init +2; Spd 20 ft., 50 ft. (average); Defense 21, touch 12, flat-footed 19 (+2 Dex, +9 natural); BAB +5; Grap +5; Atk +6 melee (1d6, bite); Full Atk +6 melee (1d6, bite) and +1 melee (1d4, 2 claws); FS 5 ft. by 5 ft.; Reach 5 ft.; SQ breath weapon (2d10; DC 13), darkvision 60 ft., fear aura (DC 13), improved grab, immunities, low-light vision; AL chaos; SV Fort +5, Ref +6, Will +2; AP 0; Rep +0; Str 10, Dex 14, Con 12, Int 8, Wis 13, Cha 12.
Skills: Hide +6, Intimidate +5, Listen +5, Move Silently +6, Speak Auran, Spot +5.
Feats: Weapon Focus (bite).
Advancement: 6–7 HD (Medium-size); 8–15 HD (Large); 16–25 HD (Huge).
Thunderbird (Adult): CR 14; Huge magical beast; HD 16d10+80; hp 168; Mas 20; Init +0; Spd 30 ft., fly 100 ft. (average); Defense 22, touch 8, flat-footed 22 (–2 size, +14 natural); BAB +16; Grap +32; Atk +23 melee (2d6+8, bite); Full Atk +23 melee (2d6+8, bite) and +21 melee (2d4+4, 2 claws); FS 15 ft. by 15 ft.; Reach 10 ft.; SQ breath weapon (8d10; DC 23), darkvision 60 ft., fear aura (DC 20), improved grab, immunities, lowlight vision; AL chaos; SV Fort +15, Ref +10, Will +8; AP 0; Rep +0; Str 26, Dex 10, Con 20, Int 12, Wis 16, Cha 14.
Skills: Hide –2, Intimidate +10, Listen +12, Move Silently +6, Speak Auran, Speak Language (any one), Spot +12.
Feats: Cleave, Multiattack, Power Attack, Weapon Focus (bite), Weapon Focus (claw).