Photographing at sunset has many benefits besides the golden light and potential for dramatic landscapes. It's also an ideal time to capture wildlife as the search for their last meal of the day.
Since the light is low, a high ISO is usually necessary for this kind of shooting, as is a fast shutter speed, and wide aperture.
Of course with all wildlife photography, the number one rule is to be kind to the animals and their environment.
In order to avoid disrupting or altering their natural behavior, I wear muted colors, stay low and quiet, and approach very slowly. I also use a long lens of 400mm which allows me to photograph from a distance so the creatures don't feel threatened.
By the way, I've created an Instagram page to share my iphone "photo journal" including the behind the scenes day-to-day of my photography adventures. Follow along here.