The Groove-billed Ani is about 34 cm (13 in) long, and weighs 70-90 g (2.5-3.2 oz). It is completely black, with a very long tail almost as long as its body. It has a huge bill with horizontal grooves along the length of the upper mandible. It is very similar to the smooth billed ani, some of which have bills as small as the Groove-billed and with grooves on the basal half. The two species are best distinguished by voice and range. In flight, the ani alternates between quick, choppy flaps and short glides.
“A 28 m. (92 ft.) observation tower dedicated to the viewing of canopy birds and other wildlife. Placed in the center of the rainforest, The Nest offers unparalleled wildlife viewing opportunities. As you ascend the 146 stairs to the top, keep your eyes peeled for monkeys, toucans, and other wildlife moving through the lower levels of the trees. Once at the top, you will be treated to an incredible 360° panoramic view of Arenal Volcano, Arenal Lake, Cerro Chato, and the Tilarán Mountain Range. This is the perfect spot to scan the canopy for birds and other wildlife amongst the treetops. With a telescope, you may even find some aquatic birds in the areas surrounding the lake Arenal.”