Technically, I'm not a student right now, and I'm not currently working in the field or on any specific project. But I'm not far removed from fieldwork, and I still enjoying spending time romping around outdoors, even if I'm not working on research.
Most of my "must have" supplies are derived from the Ten Essentials, a list of ten items generally recommended as necessities for traveling in the backcountry. If you ever work in the field (or do any sorts of recreational activities outdoors) then these ten things should always be in your pack, even for short day hikes. I'll admit I do take some liberties with the list (e.g. I won't take a map for someplace I've been tens of times) but I typically carry everything along. And, of course, I've tailored it to suit my personal style!
- Map- I prefer self-made maps using a GIS program, like ESRI's ArcGIS. My favorite maps are satellite photos with overlays of important features like roads. Satellite photo-based maps are particularly useful in the field, because oftentimes you can see trails or other geographic features on a photo that would be difficult to find on the ground.
- Compass- I always carry a compass. It's important not to keep a compass someplace it will get tossed around a lot, or anywhere near electronic equipment-- otherwise it might become uncalibrated.
- Sunglasses and sunscreen- What? You want to burn your retinas? Or get melanoma? I never go anywhere without sunglasses. Even if it's overcast.
- Extra clothing- Unless I know I'm going to be somewhere far from easily accessible roads or local communities, I often won't pack more than a rain jacket and/or hooded sweatshirt. The longer the trip, or the farther from civilization, the more extra clothing I'll carry. I almost always carry a pair of gaiters in my field pack, though. Dead useful for a whole host of situations-- everything from snow to mud to prickly, evil shrubs.
- Headlamp/flashlight- Er... I don't really carry my headlamp with me all the time. I should.
- First-aid supplies- I think I have two little first-aid kits in my field pack right now. Adhesive bandages are a necessity.
- Firestarter- I've never carried a firestarter.
- Matches- If they're not waterproof, they're not worth having.
- Knife- I prefer a multitool. Right now I carry a Leatherman Wave. I never go anywhere in the field without a pair of pliers and a knife, and this little piece of engineering has a crapload of other built-in gadgets, too, like a nail file, saw, and both Phillips- and flat-head screw-driving bits. The last thing I used it for? Pulling a frayed shoelace tip (sans aglet) through an eyelet in my trail-running shoes. I never could have done it without those pliers on-hand. You might be surprised how useful these things actually are.
- Extra Food- Mmmm... trail snacks. I love food, and I always carry a little something extra in my pack, even if I don't plan on eating it. One of my favorite field staples are Primal Strips, a meatless, vegan jerky (I'm vegetarian) that pack easily and have a long shelf-life. They have good texture and provide a lot of protein and a nice dose of salt. My favorite flavors are Hickory Smoked and Texas BBQ, but the Teriyaki and Mesquite Lime are pretty good, too.
- Duct tape- For all the jokes surrounding its innumerable uses, this stuff really has, well... innumerable uses.
- Flagging- I'm talking about plastic or fibrous flagging, the kind about an inch in width that comes in a roll. If you need to a) mark a location visually, b) if you find yourself in a tricky, heavily vegetated area in which you don't want to get turned around, or c) if you need to return to a spot for something later on, brightly-colored flagging (neon pink has always worked well for me) tied to a tree branch or shrub is simple and highly effective.
- Something to write on, and with- I prefer fine-tipped Sharpies and Rite in the Rain notebooks, even if they are a little pricey.
- GPS- Even though people have been trudging around the wilderness for centuries without technology, I'm really enamored by today's GPS units. They're unbeatable for everything from marking study sites and sampling locations to finding your way around unmarked dirt roads and two-tracks in rural Wyoming. I would have literally been incapable of finishing my workload with the BLM last summer were it not for a trusty Trimble Juno SB.