afaik, 0 for Birb 
(based on what grimtools pet database shows and yes, it varies from pet to pet)
Think of it more like, Lightning strike for example deals the amount of damage listed in the skill itself and a percentage of any flat damage bonus to pets from sources like devotions, items and auras.
That makes a lot of sense, thank you! 
@Maya Hello! I’m starting to play for the first time. I want to try pet. Please tell me what should I choose? I want to play as a necromancer. Should I choose a ritualist? The fact that I don’t see a cabalist in the list of guide, why? And where can I find a guide on how to level up from the begining?
I really hope for your help.
First of all, welcome to the forums and to the game 
If starting for the first time, I would recommend Conjurer (shaman + occultist), since Necromancer is a bit more advanced.
Regarding guides, the pdf at the top of the thread is the only one I have. Rest are all endgame builds that contain very little info for new players.
Cabalist, I am not a fan of atm due to heavy item investment required to make it perform adequately, to my standards.
Update for the current Playtest build. (Note that this is based on my experiences with my own builds)
First things first, Zantai essentially wrote a love letter to pet builds atm.
Now, Beastcaller, Trinkets, Diviner are all performing similarly for me.
Ghol Blightfiends feel like they took a heavy nerf (based on kill time vs callagadra)
Lost Soul Skeleton Cabalist has went on to become my best pet build atm with 1:50 min callagadra kill and around 5:20 min naked Crucible with extra spawn (both using mogdrogen’s elixir however)
The Calcium kind -
(around 3 minute callagadra and 5:30 minute sr75-76 with lucky mutators)
Ever wanted to play with Skeletons, but Cabalist just didn’t vibe enough with you?
Ever wanted to play as a Pet Ritualist, but not a fan of smelly Zombies?
.
Note - was tested on current playtest patch, so subject to changes in the future once patch goes live
.
Edit - also 5:30 minutes for Crucible 150-170 without Blessings/Banner/Beacon and with Extra Spawn
I’ve been running a similar build, but a Cabalist version. I’ve been enjoying the Vitality/Bleed synergy with my skeletons. Here I thought I had a unique build, and you drop this one today.
I wanted to see how setless Skeletons fared atm, Bleed felt like a good choice with how high we could get Primal Bond to
It is also possible that I may have sent a birb to spy on your build and report back 
My build came into existence from necessity. I was trying to build towards The Lost Souls Cabalist, but the game refuses to drop the plans for this set. I used the random pieces of gear I’ve got to make my build as I saw an opportunity to make a Vitality/Bleed pet build instead.
It turns out that my new build can easily handle all the content I’ve encountered in Ultimate, SRs, and the Crucible. I’m enjoying playing my build so much, I may not even go to the Lost Souls set if I ever manage to get the entire set.
Wanted to try and see how the build fared with full Vitality -
1:50 minute Callagadra kill
10 second Crate kill
1:30 minute Ravager of Flesh
1 minute Mogdrogen
It feels like Bleed without Briarthorns still have some catching up to do 
Note - This is based on Playtest patch, not live.
