Thunderbird (CR 12)

Huge Magical Beast
Alignment: Always chaotic good
Initiative: +3 (Dex); Senses: darkvision 60 ft., Listen +13, and Spot +20

AC: 18 (-2 size, +3 Dex, +7 natural), touch 11, flat-footed 15
Hit Dice: 15d10+90 (172 hp)
Fort +15, Ref +12, Will +11
Speed: 20 ft., fly 80 ft. (good)
Space: 15 ft./10 ft.
Base Attack +15; Grapple +32
Attack: Talon +22 melee
Full Attack: 2 talons +22 melee and bite +20 melee
Damage: Talon 1d8+8, Bite 2d6+4
Special Attacks/Actions: Spell-like abilities
Abilities: Str 28, Dex 17, Con 22, Int 12, Wis 19, Cha 17
Special Qualities: immunity to electricity and sonic, resistance to acid 10 and fire 10, SR 25
Feats: Flyby Attack; Hover; Iron Will; Multiattack; Power Attack; Snatch
Skills: Intimidate +21, Knowledge (nature) +10, Listen +13, Spot +20, and Survival +4 (+6 aboveground)
Advancement: 16-30 HD (Huge); 31-45 HD (Gargantuan)
Climate/Terrain: Temperate deserts
Organization: Solitary
Treasure/Possessions: Standard coins; double goods; double items

Source: Sandstorm

Spell-Like Abilities: At will - call lightning (DC 16), fog cloud, shout (DC 17); 3/day - call lightning storm (DC 18), greater shout (DC 21), sandstorm, solid fog; 1/day - earthquake (DC 21). Caster level 15th.

Skills: Thunderbirds have a +4 racial bonus on Spot checks.

An angry thunderbird is a terrible opponent. It hovers over the battlefield, striking with talons and beak while its wings stir up storm winds on the ground below. With a blink of its flashing eyes, it can call down lightning from a clear sky and blast foes with crashes of thunder.