Any of today's digital cameras will take decent pictures of large birds, sitting still in good light, and not far away. These conditions are of course rare, especially when birding in Ecuador. Equipping yourself with the right gear is essential if you want to capture usable images of birds under real-world conditions.

Some of the problems you'll face in Ecuador are:

• You will spend much of your time under the forest canopy, or birding at dawn or dusk, when the light is dim. The small sensors in compact digicams will yield images with unacceptable noise levels. The large sensors of DSLR cameras are the only practical way to cut down the noise. You might want to use flash as well, to reduce the noise even further and increase shutter speeds. 
• You will often find yourself pointing up to shoot birds, and images will be no more than silhouettes. The only way to solve this problem is to use an external flash that reaches far enough to illuminate the subject. Shooting up often involves high-contrast scenes, where compact digicams will show chromatic aberrations (purple fringing) or will loose detail in the highlights. A decent DSLR with flash will help avoid these problems.
• Small birds tend to move quickly and unpredictably, and you'll probably shoot some birds in flight. This means you need a responsive camera that doesn't take 2 seconds to focus. Compact digicams are faster than they used to be, but again the best solution is to use a DSLR. The lower noise levels of a DSLR will also let you use higher ISO settings and faster shutter speeds, to minimize motion blur.
• You will find yourself using the full extent of your telephoto lens for most shots, so a camera with image stabilization is essential. The alternative of a tripod is unattractive because of the added bulk and weight. Also, many birds do not sit still long enough to get the tripod set up. In this respect, a tripod is worse than an unresponsive camera.
• When using flash, a fast recycle time is important so that you can shoot the same subject multiple times in quick succession. This requires the use of an external flash unit instead of your camera's built-in flash.
• An experienced birder or guide will spot small birds at a great distance. Even with a long telephoto lens, your subject will fill only a tiny fraction of the frame. That is, your cropped bird photos will have too few pixels to provide decent image quality. The only way to capture these subjects is through a high-power spotting scope. This requires lugging heavy and expensive gear, so you might decide to forego photos of this type.
• You'll probably spend much of your time hiking on steep or muddy trails, under hot and very humid conditions. It will probably rain on you as well. This calls for taking no more photo gear than you really need.

Anticipating these issues, I decided to replace my Panasonic FZ10 compact superzoom camera with a Nikon D40 DSLR for the Ecuador trip. I added the new Nikon 55-200mm VR telephoto lens (for a 300mm-equivalent) and the SB400 flash. I did not take a tripod. This was a combination that solved the problems pretty well, while keeping within my budget.

During the trip, I found myself using the SB400 flash a lot. In hindsight, I should have taken rechargeable batteries. As it was, I got through more than a dozen alkaline batteries.

Surprisingly, few birds are perturbed by camera flash. You'll find yourself able to take several pictures of the same subject when needed. But be aware that flash will distort the appearance of birds with iridescent feathers, such as hummingbirds. You'll also experience "red-eye", although it's often not red in birds.