Please be aware that the use of Fipronil - the ingredient in Frontline - is extremely dangerous to humans who eat the eggs or meat of the birds treated. There was a huge "recall/culling" of birds in EU last summer. If you have used this product - there is a lengthy withdrawal time...
I have no idea - I was planning on 2 tablespoon's in 3.3 gallons - I would only measure in ml if I was administering a specific medication that required use of a syringe. This is going in a sprayer.
I also wanted to add that for those who have been using Frontline/Fipronil for Any pest - DON'T !! Read the recall that occurred in Europe... https://en.wikipedia.org/wiki/2017_Fipronil_eggs_contamination
You are correct in reading the label for the Elector - but you miss the directions that say to dilute it ... So - actually - the Monterey Spray could stand to be diluted as well !!
Dilute 3 fl. oz. of product in 10 gallons of water. Spinosad concentration in the dilution: ~1035 ppm** = mg/L...
Also - please take great care to not cross-contaminate !! Wash hands and utensils - even change shoes or step in a bleach solution before going from one pen to the other - just to be safe.
I would recommend calling a wildlife rehabber in your area - these people are very in tuned with reports of diseases in wild birds. If you are in a rural area - I would also make contact with any local farmers who have poultry - as this does sound like something that crosses species. I do hope...