My education and work history are way more geared towards management of wild populations than zoos, but the idea of working in the latter environment has been a fun dream since I was a kid. Off the top of my head:
I spent a year on a project that was monitoring red-winged blackbirds, and by extension a small local population of endangered tricolored blackbirds. Mainly assessing population density, resource use between marshland and neighboring dairies (they REALLY love the free grain), and interspecific competition observed in mixed flocks that also included brewer's blackbirds, brown-headed cowbirds, European starlings, etc. etc.
Spent three field seasons with the University of California as an agricultural tech, and bounced around several projects in the process. This is where I got a lot of my entomology experience, as pest + pollinator surveys are a constant need during the spring/summer growing season, and I spent a lot of hours camped out in the entomology field lab ID'ing insects from field sweeps. We did some trials regarding invasive plant removal and crop pathology, mainly in black-eyed peas, which was something fun and different. Last but not least (and funnily enough the most "prestigious") was a study that took up the entirety of my final season, involving management of spider mite populations in silage corn crops using chemical control in tandem with predatory mites.
The better part of two years while I was still in school, I did informal bird guiding that earned a bit of money - and birding was what I would have been doing on the weekends anyway. I lived in the midst of a Pacific Flyway hotspot and had been birding the region for a few years at that point, so when a friend of a friend would show up during migration season I generally knew where to go for local rarities and chased a few vagrant species.
My health has been on-and-off crap for the past few years, and so a lot of the wildlife biology jobs that feature remote field sites, or last only a season and require a move (aka many of them) unfortunately don't work for me, so I've pivoted to a mix of agricultural entomology and science education, which worked out pretty well. The current world pandemic situation hasn't been fantastic in regard to any of that, haha, but what can you do
