Interference with standard friendly mob spawn

I have the same issue. The birds seem to take up possible pig/cow/etc mob spawns. 

Issue:
1) birds are now taking up the majority of potential animal spawns
    a) cows, sheep, pigs are drastically spawning less

In the config I changed the nest rate from 60 to 10:

    # How frequently nests should spawn in the world. (0 = disabled) [range: 0 ~ 500, default: 60]
    I:genRate=10

Question
1)  Do I need to also change the bird spawn size max? 
    a) Most spawn between 2 and 5
    b) Would changing the max to 2 make the pigs, cows, etc spawn more frequently?
2) Does the nest rate increase the amount of bird entities there are? (ie the higher the nest rate, the lower the pigs, cows, etc?)

    seagull {
    # Allow seagulls to spawn [default: true]
    B:allowSpawning=true

    # Seagull spawn rate. (0 = Rare, 100 = Common) [range: 0 ~ 100, default: 12]
    I:spawnRate=12

    # Seagull maximum group size [range: 0 ~ 50, default: 5]
    I:spawnSizeMax=5

    # Seagull minimum group size [range: 0 ~ 50, default: 2]
    I:spawnSizeMin=2
    }


Thank you.


Edit: I am going to test by trying this:
1) changing the min to 1 and the max to 2 for all birds
2) see if the nest gen rate makes a difference after doing the above change

Edited Dec 10, 2019

Another Related Question: 
If I delete these lines of code from the config:
1) will the vanilla minecraft parrots still spawn?
2) will the peafowls from the mod Animania still spawn?

parrot {
# Allow parrots to spawn [default: true]
B:allowSpawning=true

# Parrot spawn rate. (0 = Rare, 100 = Common) [range: 0 ~ 100, default: 6]
I:spawnRate=6

# Parrot maximum group size [range: 0 ~ 50, default: 5]
I:spawnSizeMax=5

# Parrot minimum group size [range: 0 ~ 50, default: 2]
I:spawnSizeMin=2
}

 

and

 

peafowl {
# Allow peafowls to spawn [default: true]
B:allowSpawning=true

# Peafowl spawn rate. (0 = Rare, 100 = Common) [range: 0 ~ 100, default: 6]
I:spawnRate=6

# Peafowl maximum group size [range: 0 ~ 50, default: 5]
I:spawnSizeMax=5

# Peafowl minimum group size [range: 0 ~ 50, default: 2]
I:spawnSizeMin=2
}

 

Thank you.

Two screenshots from my world, taken of neighboring areas in the same biome, right after the area freshly loaded.  All white/grey creatures are birds, the brown ones are butterflies from another mod.

 

* Spawn rates for all birds set to between 1/10 and 1/20 of their original value

* Number of birds minimum/maximum per group left at default values

 

 

* Spawn rates for all birds set to between 1/10 and 1/20 of their original value

* Min/max set to 0-1 birds per group

 

 

Does anyone know if the configuration accepts decimals between 0 and 1, for any of these numbers?

 Any ideas for how I can get the natural spawnrate of birds down to maybe 1/3 or less of picture 2's amount?

Any updates on this? Thank you.

I'm very sorry, I had a similar issue reported to this and I confused the two. Apologies for not responding to this issue at all. 

Unfortunately the behaviour you're experiencing is an unfortunate side effect of the mod. As there are 40+ new birds added, the spawns are additive and do tend to interfere with the base spawns of the minecraft animals. The only fix I can recommend is to install something like CustomSpawner (or a similar mod that is used to control the spawns of creatures)

I've updated a lot of the config in recent versions. If you wish to turn the birds off, you will still be able to find their eggs in nests, which hopefully could be a good compromise.