Pack light:  I find that my trips tend to be more pleasant when I am not lugging around a ton of baggage.  Usually birding trips only require casual dress so that will help reduce the load.  My typical configuration usually involves two bags.  One carry on camera bag with all of my camera gear, medications and other valuables are in.  Be sure to make sure that your camera bag complies with the carry-on requirements of the airline that you will be flying with.  The other is a checked bag that I carry my tripod, clothes, toiletries… in. 

What goes where:  It is important to keep in mind that lithium batteries are not allowed in checked baggage and it is also important that tools might not be OK to carry on.  I have had small screw drivers and even allen wrenches confiscated at airport security checkpoints so I always make sure they are in my checked baggage. 

Packing Checklist:  A checklist really comes in handy is when it comes to chargers, wires, batteries, memory cards and so on.  One thing about photography is that there are an awful lot of gadgets and parts that need to come along.  I always prepare a personal check list that includes all cables, power adaptors, memory cards, lens caps and batteries to make sure I haven’t forgotten anything.  Finding a place to buy a USB cable for your hard drive or a battery charger for your camera battery can be a real challenge on a birding trip.

Flashlight:  A flashlight is a must.  During trips there is usually at least one opportunity for a night hike.  During these hikes it is necessary to have a flash light and/or head lamp so you can see where you are going.

Meds:  Basic medications are another thing that everyone needs to have on hand.  Pain relievers, anti-diarrhea meds, antihistamine and so on can make a big difference on how comfortable you are while travelling.  Some people like to check with their doctor before travelling to get prescriptions for antibiotics or other medicines that they might need while travelling.  Again this is an area where a checklist can really come in handy.  If you take regular medications you definitely don’t want to be without them during the trip because you forgot them at home. 

Sun Screen and Insect Repellant:  Sun screen and insect repellent are definitely recommended.  The tropical sun can give a nasty sunburn so it is always a good idea to have plenty of sun screen handy along with a hat that has a wide brim.  Long-sleeve shirts are also usually a good idea to help with sun protection.  Nothing can spoil a trip like painful and itchy insect bites.  I always suggest bringing some insect spray/lotion.  Nothing I have used is effective as DEET so I do recommend DEET based insect repellant.  Sunglasses can also be a life-saver.

Footwear:  Comfortable shoes are a must.  We usually try to make sure the trips aren’t too strenuous so unless specified serious hiking boots are not necessary.  It is important to have comfortable walking shoes.  If you have some that are water-proof/resistant that is an extra plus.  Sometimes we might encounter a puddle or heavy dew on the vegetation that could result in wet feet.  Sometimes I will even bring rubber boots with me provided I have enough room in my checked bag.  They can come in very handy when the trails get muddy.

Clothing:  Weather can be unpredictable so it is always a good idea to have a light rain jacket and/or rain pants in your luggage.  I also carry a couple of plastic bags to cover cameras and other gear with in case of an unexpected shower.  I also carry an inexpensive rain poncho (the type you can buy at Walmart for less than $10) that I can keep with me at all times in case of rain.

One lesson I learned the hard way is to never leave home without some warm clothes.  While most trips don’t encounter extreme weather, it can get cold when in the mountains and sometimes a freak cold front can blow through unexpectedly.  I always bring a couple of sweaters/light jackets that I can layer on in case it gets cold. 

I always try to bring enough socks that I can have a fresh pair each day, athlete’s foot is no fun.  I usually also carry laundry detergent with me so I can wash socks and undergarments and even shirts and pants during the trip so I don’t have to carry quite so many.  

I prefer to wear long pants during birding trips so I don’t have to worry as much about biting insects and thorny or poisonous plants.  Long-sleeve shirts and a good shade hat can also be beneficial. 

Field Guide:  I usually like to bring a field guide with me on bird photography trips.  Sometimes Smartphone apps are available so you don’t have to lug a heavy book with you.  

Notebook and Pen:  Some people find it useful to bring a notebook to keep a record of the trip.  It can also be handy to have a pen with you on the airplane to fill out customs and immigration forms on your way to your destination.

Water Bottle:  I often like to carry an insulated water bottle with me on birding trips.

Day Pack:  It can be quite convenient to have a day pack to carry extra batteries, memory cards, cleaning cloth, rain poncho, snacks, water... while out for the day.

Binoculars:  Binoculars can come in handy to help identify birds when out in the field.

Camera Gear:  My typical gear on a trip like this consists of two camera bodies, a long telephoto lens, a telephoto zoom lens and a macro lens.  I used to also carry a wide-standard lens but now I tend to just use my iphone for people and scenery photos.

I find carrying two cameras to be a great idea.  One never knows when a camera might fail or when an accident might happen.  Unfortunately both have happened on previous trips and those who were carrying an appropriate back-up suffered the least from such occurrences.  When we are in a place like Costa Rica there aren’t camera stores handy so purchasing a replacement camera on the trip really isn’t an option.  I strongly encourage you to carry two camera bodies and both should be something you would be happy using for the whole trip.  In the past there was an incident where a backup camera was a very outdated rebel body that really wasn’t up to the demands of the trip causing considerable frustration for its owner when his main camera was knocked on the ground and broken.

My main lens is a 500mm f/4 lens that I often use along with a 1.4x teleconverter.  I usually use this lens hand-held but do always bring a tripod along as it can be a big help when the light is low or if we are photographing birds visiting feeders. 

I use a 100-400mm lens frequently to photograph hummingbirds, birds visiting feeders at close range and the occasional large mammal that we might encounter.  I also find it to be a nice lens for close-up types of shots of subjects like flowers, dragonflies, butterflies…

Recently I have started carrying a 35mm macro lens that I use along with a 420EX flash with a diffuser that I mount in the hot shoe of my camera.  I find that this setup works great on light walks and for subjects like insects, frogs and small flowers.

Some of the scenery encountered during birding trips is breathtaking and some people find it useful to carry a wide-normal lens like a 16-35mm or 24-70mm lens to cover this type of photography.

All of my cameras, lenses, battery chargers, memory cards, cables, card readers, laptop computer and other valuables are packed in a camera backpack and carried on the airplane with me.  I have found bags from companies like Thinktank or Lowepro… are great for this.  Make sure that your bag is small enough to fit in the overhead bin of that aircraft or under the seat to avoid having to check it.

Tripod:  In my checked bag I like to pack my tripod legs and gimbal head, usually padded by my clothes.