While garter snakes are generally solitary creatures they generally hibernate in large numbers to prevent heat loss and keep their bodies warm.
Garter snake in house siding.
They prefer to live in a warm and damp environment.
These are individuals that needed to be relocated.
Through gaps between brick and siding osborne also warns that snakes can get inside by slipping between bricks if mortar is missing and also between bricks and siding on the exterior of your home.
I had a family of garter snakes living inside my siding exactly same situation as you had when i put the deck on i removed siding to attach the ledger and half a dozen snakes came out of the lower trim piece just like you describe.
Visually inspect your siding for openings through which the snakes can find access.
Garter snakes living in vinyl siding removal.
The snakes climb up into the openings and use the space behind the siding.
The most distinguishable feature of garter snake is a light shaded stripe running along its back.
Yards and gardens easily become their cozy homes so they can feed themselves on earthworms tadpoles insects mice lizards and other reptiles found in this area.
If the affected panels of your siding are easy to remove doing so will allow the snakes a quick exit before.
Lifting up the loose edges allows for some of the snakes to drop out.
That one does not look like any of those so most unlikely it is poisonous.