I am a Zoology graduate who initially took a job training dogs but since I found out I wasn't a massive fan of the environment, I'm actually doing more admin based roles and maybe eventually would like to align my animal and admin interest by working in a Zoological museum or as a zoo registrar.
Gaining a degree is literally the first step in the process; you need to have a good think early on about where you want it to take you and its good you already are starting to do that. You will have to volunteer a long time before you get something decent pay wise for the kind of job you are looking for. I spent 4 years volunteering with animals in various capacity every weekend; this was through first my local animal sanctuary and then when I was old enough at my zoo both in the education department and with the Pets keepers. Any animal experience helps. Trainee keeper jobs hardly ever came up when I was there; not that I would do one now with this particular zoo after seeing all the management changes that occurred but that's another story. Even for a zoo keeper job, a degree is quickly becoming the standard as opposed to a Level 3 animal qualification. Some of the keepers who worked where I volunteered even had Masters degrees. Chester Zoo for example list a degree for almost every zoologically related job. With that said they, they are the best zoo in the country and so its easy to see why they ask for that kind of calibre.
For a conservation role in the UK, even as an entry level ecologist, they will want to see experience, possibly to already have wildlife licenses (Great Crested Newt, Bats etc.), habitat survey experience and maybe even extra training like with GIS systems. Competition is just so fierce. I think generally you will have to specialise at some point or another unless you do that kind of broad surveying as conservation projects will have some kind of focus; that's how they get their funding.
Please do not pay money upfront to volunteer abroad; this seems to do more harm than good in my eyes. Why would those kind of organisations ever take on paid staff if they can get a steady stream of volunteers willing to pay. Obviously be dubious of all sources but I remember reading this post by a Guest Blogger on the subject who lives in South Africa and can't even afford to volunteer in his own country because of all the money making schemes going on out of this: https://africageographic.com/blog/ca...nteer-country/
I would start by volunteering locally with a conservation group; you may be able to have someone you habitat surveys. If you are also thinking of ecology, also take courses in botany; I did a module in Plant Identification at my university which opens the door to completing a qualification with the official Botanical Society. Our lecturer taught us in our unis botanical gardens and leads the local botanical group; incredibly clever man and very interesting to learn from. Always found it fascinating that he could look at a small patch of grass and see so much there, running off so many latin names. Hopefully if you do decide to do zoology you will have passionate lecturers wherever you go!
I did see a job opening once through ZSL that is probably along the lines of something you are after; I think it was working with Giant Salamanders abroad. However the essential and desirable criteria was absolutely huge; you needed to speak the local language fluently, have all of the animal and conservation experience required and even management experience I believe.
Following on, to give yourself a good idea of how much work is required to obtain one of these jobs, look at job descriptions and person specifications. You will want to aim to give yourself enough experience to at least cover all of the essential criteria and some of the desirable criteria. Environment Jobs and BIAZA are generally my go to's but there are others just a Google search away. I've posted the links to them below. Good luck