My "New World" Campaign (Devil Bat)

Devil Bat (From Deadlands D20)
Large Magical Beast
Hit Dice: 5d10+15
Speed: 10ft., fly 45 ft. (poor)
Armor Class: 14 (-1 size, +2 Dex, +3 natural), touch 11, flat-footed 12
Base Attack/Grapple: +5/+13
Attack: Claw +8 melee (1d6+4)
Full Attack: 2 claw +8 melee (1d6+4) and bite +3 melee (1d8+2)
Space/Reach: 10ft./10ft.
Special Attacks: Improved grab
Special Qualities: -
Saves: Fort +7, Ref +5, Will +1
Abilities: Str 18, Dex 13, Con 16, Int 4, Wis 10, Cha 6
Skills: Hide +10, Listen +10, Move Silently +10
Feats: Alertness, Stealthy
Environment: Temperate hills
Organization: Pack (1-6)
Challenge Rating: 5
Treasure: None
Alignment: Neutral evil
Advancement: 6-8 HD (Large); 9-15 HD (Huge)
Level Adjustment: -
The Sioux call the winged terrors “kinyan tiwicakte” or “flying murderer.” Devil bats are nocturnal predators who hunt in packs of one to six. They attack by racing from the night and grabbing prey with their taloned feet, then dropping them to the ground and eating the gooey remains.
These flying horrors are batlike humanoids with leathery skin and tremendous wings. They eat lesser prey alive by rending it with their claws and savage teeth. Larger prey is dashed to the ground as described above and shared by the pack.
Combat
Death From Above (Ex): When a devil bat scores a hit, it makes an immediate grapple check using its improved grab. If this is also successful, the creature rises its normal flying speed (45 feet) into the air and drops its prey for additional falling damage (typically 4d6).
The best thing for a traveler to do once she’s in the grasp of a devil bat is to grab hold of its ankles and hang on for dear life. Should this occur, make a second grapple check between the two. If the character wins, he holds on. If not, the thing shakes him off and he falls to the ground as above.
Echo Location (Ex): Like real bats, devil bats use echo location to “see.” Prey which remains stock still (no movement whatsoever) among solid obstacles gains +5 to Hide checks, and may hide even in the middle of a fight (unless actually in melee or adjacent to the thing).
Skills: Devil bats receive a +8 racial bonus to Hide and Move Silently when flying (which they use to descend upon their prey from above).