Crow Fiend

[Calmar]

Hi! :)
This is my first monster in a long time and my first pathfinder monster, so I'm pretty sure there aree a few things that need fixing. Please tell me you opinions.
Particularly I am not sure if the challenge rating is too low, and if it needs more HD.

Spoiler:

Crow Fiend

This black-winged creature looks like a hideous female human with the head of a crow and vicious claws instead of hands and bird's legs.

Crow fiends, also known as crow witches or daughters of Brân, are servants of the demon queen of slaughter and destruction. They are sent into the mortal world to advance the cause of their horrible mistress by bolstering her worshipers and slaughtering her opponents. Sometimes, these creatures appear as inconspicious, or even beautiful women that infiltrate mortal society, luring mortal men into their doom.
In battle, these demons usually call upon lightning to decimate their enemies and shred their opponents to pieces with their powerful claws.

CROW FIEND CR 5
CE Medium outsider (chaotic, demon, evil, extraplanar)
[B]Init +3 Senses darkvision 120 ft., low-light vision; Perception +11
Languages Abyssal, Celestial, Common, Draconic, telepathy 100 ft.
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AC 18 (+3 Dex, +4 natural, +1 Dodge), touch 14, flat-footed 14
hp 57 (6d10+24 HD); DR 10/cold iron or good
Immune electricity and poison
Resist acid 10, cold 10, fire 10; SR 16
Fort +9, Ref +5, Will +7
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Speed 30 ft. (6 squares), fly 50 ft. (average)
Melee 2 claws +10 (1d6+4), bite +5 (1d8+2)
Melee 2 claws +8 (1d6+8), bite +3 (1d8+4) with Power Attack
Space 5 ft.; Reach 5 ft.
Base Atk +6; CMB +10; CMD 23
Atk Options rage 8 rounds/day, rend (2 claws, 1d6+6)
Special Actions none
Combat Gear none
Spell-Like Abilities (CL 6th; concentration +8):
1/day—call lightning (DC 15)
3/day—summon swarm (murder of crows only)
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Abilities Str 19, Dex 16, Con 18, Int 13, Wis 15, Cha 14
SQ none
Feats Dodge, Flyby Attack, Power Attack
Skills Bluff +11, Fly +12, Intimidate +11, Knowledge (planes) +10, Perception +11, Sense Motive +11, Stealth +12
Possessions none
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Rage (Ex): A crow fiend you can enter a fearsome rage, like a 1st-level barbarian, for a number of rounds per day equal to 4 + its Constitution modifier. This ability is in all regards identical to that of a 1st-level barbarian.

Crow fiends are often barbarians, sorcerers, or bards.

The crow fiend has Good Fort and Will saves.

Its class skills and base ranks are:
Bluff +6, Craft +0, Fly +6, Intimidate +6, Knowledge (religion) +0, Knowledge (planes) +6, Perception +6, Sense Motive +6, Stealth +6, Survival +0 (should have two more, but I can't think of any useful skills)

I want it to be able to assume the shape of a Small (or smaller) crow and a humanoid (similar to a green hag). Should I give it alter self as a spell-like ability, or the change shape ability?

[Mauril]

Darkvision should probably be 90, which is rather long range for darkvision.

Bite attacks are primary attacks, and so its bite ought to be Bite +10 to attacks and +4 to damage. Also, both attack types are listed as a damage die too high. Medium claws deal 1d4 and medium bites deal 1d6. If you want them to deal d6/d8, they will need to take Improved Natural Attack or have some sort of special ability in their stat block about dealing damage as a creature one size larger.

"Atk Options" should just be listed as "Special Attacks".

Formatting-wise, usually power attack entries are not listed separately. Also, it should be "Immune electricity, poison" without the "and", but that's just an incredibly minor thing. "Special Actions" and "Combat Gear" should be dropped from the entry. As should SQ if they have none.

Otherwise, it looks good. Tough, especially when you consider that this thing is a viable opponent for a level 2 party.

As far as shapechanging into a crow, I'd go with the Change Shape special ability, noting that it acts as Alter Self and Beast Shape II (crows only). Crows are tiny animals according to the rules, and tengu are medium humanoids, so you'd need both to assume either form.