Should I go for a physics degree or a biology/conservation degree?

Shouldn't you be studying engineering if you want to specialise in robotics? Also I'm just curious, how are robots going to help animals?

i will be finishing my biology bachelors degree in a few weeks. if youre in it because you want to work at a petting zoo you will be unpleasantly surprised that its actually a science degree. many people drop out in the first few semesters when this hits them.
on the other hand if you kind of want a bit of everything biology is just right in my opinion. we had courses in mathematics, physics, tons of chemistry, anatomical biology and of course ecology. it was quite modular too, i took a course in bionics (designing machines based on biology basically) and you can focus during your masters later.
look into the programs offered to you and see if they have courses involving robotics/engineering etc. and decide from there.
i personally loved every minute of biology and it gives you a quite nice toolkit to switch into all kinds of master programs and fields. quite fun practicals and field work too.

if this sounds too soft for you i recommend just going full on engineering and picking ecology stuff on the side.

i also want to mention that you know jack shit at 18 and you will change a lot personality wise in the next couple of years so if you want to hear my 2ct you should keep your options open as much as possible.