i use the pibella.
it is the smallest and most leakproof one (plus you can use it to squeegee yer squishies after), but it has the steepest learning curve. i practiced with mine at home for a couple of days before taking it outside, but i am now DONE with straining my knees to squat and peeing into my shoes.
It depends a bit on where I am (different environments require slightly different gear), but some universals are:
Pocket knife, multi-tool, folding trowel, compass (old school), GPS (usually a Garmin), 10x hand lens (doubles as a macro-lens for a smartphone), larger magnifying lens (nice for larger things, not needing to squint, and as an emergency macro lens for a normal sized camera), pocket sized spotting scope/semi-microscope (this is small enough that I have it with me even if I have binoculars with me), flashlight or headlamp, thick plastic bags (for samples, to keep dry when sitting on something wet, or to keep equipment dry), bandannas (many uses), heavy cord/light rope (3-5 meters), hat, camera (type and lenses vary), smartphone with a collection of useful apps, small umbrella (sometimes a raincoat is too hot, and it’s good for shade and for a dry area to work), steel water-bottle, sunglasses, power bank (for smartphone and to recharge flashlight if needed), notebook (waterproof) and pen/pencil, lighter (and sometimes a magnesium bar), rain-fly for pack, and a folding fan (nice to have in hot weather, and you can use it to gently blow dirt off of things).
While that’s a long-ish list, none of it other than the camera and water-bottle takes up much room. It all easily fits into a standard day-pack with room to spare. Most of it stays in a secondary shoulder-bag inside the pack.
For a pack, I prefer a top-loading type with a drawstring closure and a small sipper top panel that closes over the entire pack. This type tends to be more durable, comfortable, doesn’t get caught on brush, and the top pocket sticks up a bit ensuring that the rain-fly stays on properly. Admittedly, accessing what is inside is not as easy as with some other pack styles, but if you’ve organized your bag and gear well it’s not an issue.
Since I often am alone and in black bear, cougar and wolf country I carry bear spray
My shoulders are garbage so I travel as light as possible. I have a little string backpack that I might shove a lightweight raincoat, water bottle and a small plastic container into. I try to put as much kit in my pockets as I can without looking like a lunatic on public transport. I also have a cheap bumbag for extra kit, or summertime when the heat necessitates wearing less pocket clothing.
Kit:
Sony A6000
Long lens for birds etc
Raynox macro lens. This clips onto the end of the long lens for instant long to macro conversion. I can snap away at insects and whip it off in a heartbeat if a good bird flies by. Means I don’t have to carry a standalone ‘proper’ macro lens.
Smartphone with clip-on macro lens
Powerbank, not that I need it much I’ve found
Stainless steel chopsticks. Good for prodding things.
Hat and sunnies all year round. This is Australia after all!
Washable shoes. I’d rather just get my feet wet/dirty than wear heavy boots.
Pocket change, for that all important post-ramble coffee and cake ^_^
Interesting thread!
When I’m out running, I always take
When I’m biking, I’ve also got my bluetooth microphone (a Sony ECMAW4 Wireless Microphone) which I clip onto my helmet so I can make observations (geotagged, timestamped audio notes) while riding. I use a Bic ballpoint pen as a scale for all my roadkill photos (one day I should swap it out with a short ruler but the pen does the job).
If there’s a chance of rain (or if it is raining), I have a clear plastic bag so I can keep using my iPhone in any weather. Taking photos with an iPhone is a bag in the rain doesn’t work well but I can continue to make audio notes of everything I’m seeing and hearing.
When I’m out walking, I take my DSLR kit with a 28 mm lens, 90 mm macro lens with 50 mm extension tubes, and a 300 mm lens. And plenty of vials and plastic bags. If it’s available, I take my wife’s Garmin GPSMAP64 for more accurate GPS tracking. Otherwise that gets done by my iPhone.
But no chopsticks. I’d not thought of chopsticks!
Just curious, does the bear spray actually work (hopefully you never have to use it!)?
Interesting how much a field kit can change in a year! Right now whenever I go out on lengthier excisions I bring:
A camera bag holding all of my equipment
A newer DSLR with the same macro and telephoto lenses
A small Olympus TG-5 for general photos and underwater stuff (which happens a lot more often than you think!)
My phone with an app that creates a gps file so I can apply location metadata to any photo I take in the field
misc. minor things (cleaning kits, extra batteries, snacks for really big trips, etc.)
Olympus TG-5
iPhone X
Sunglasses, sun hat, sunscreen (the joys of living in Egypt)
Sanitiser
Nikon Binoculars
Snacks!
Welcome to the forum, @youssefelnahas!
It’s nice to see someone from a neighbouring country.
Thanks. We need to pick up our game, I’m always jealous when I look at the map and see how many observations there are in Israel and Palestine compared to us!
We had one occasion where just the sound of the safety being pulled was enough to cause an unsuspecting approaching grizzly to change course by 90 degrees and high tail away.
Of course the main is husband with flashlight. :D
But usually at daytime it’s 2 cameras with macro and tele lenses (Nikon D750/5100). If on a vacation I take a bag with me for cameras, food, water, smartphone for quick plant shots. If anyone asked me I also bring containers for collecting insects.
A few things that haven’t been mentioned, which I keep in the car:
With the exception of the space blanket, all of these have either been used to get out of a sticky situation, or were bought because they would have gotten me out of such a situation much faster/easier if I’d had them available at the time. Always good to be prepared if you are going solo out on rugged roads and/or out of cell coverage.
Small kit: 10x Coddington loupe, forensic scale, smartphone.
Large kit: as above but add; longer ruler, 14x hastings triplet loupe, pad and pencil, micro tweezers from the hardware store, scalpel, piece of cork, mounting pins, reading glasses
You carry a phone and a phone? 
Yes, one is a xylophone.
I have a net, petri dishes (for close up shots), kneeling pads, a magnifying glass, notepad, pens, pencils, headlamp, Canon Rebel T6 a macro lens and a 75-300MM Lens, I also have a nature vest with extra pockets to carry a whole number of things like a first aid kit, tissues, and certain tools. I also have a fanny pack full of extra stuff. I also have a trusty hiking stick to point out things to other naturalists and people. I even have wide range of hats just in case. I never leave home without my phone just in case the camera dies or if I have an emergency. I also have a pair of hiking boots from Colombia which are pretty good. I also carry around with me my pair of Bushnell Binoculars. I have a binocular harness and a new camera shoulder strap for better range of motion of the neck and body. I That is basically all the gear I have that helps me on a hike. I gave you the full list of what I carry around. I also wear long pants when I go bushwhacking. It is not a lot but it is good. I do sometimes carry a few guides on my just to use in the car just as reading material to and from my destination.
What app do you use for gps files? I haven’t been able to find a good one - I have an iPhone.
Something called Geotag photos. It’s free for 3 tracks then it costs $12 for unlimited tracks