Venturing into Caro Lake on International Expeditions’ Amazon River tour, visitors are likely to spot some of the 13 species of primates that call this region home. Looking closely after the monkeys, however, offers an interesting opportunity for birders. Trailing behind are often flocks of greater ani, a distinctive black bird.

These birds feed primarily on insects, making monkeys a good foraging partner. As the mammals move and search for food, they stir up a feast for the greater ani. According to the Cornell University Lab of Ornithology, the birds forage from forest understory to canopy, most frequently in midstory along the water, offering adequate opportunities to view.

Look for a large black cuckoo with an especially long, black tail. Plumage is similar between sexes — glossy black with slight bronze-green edging on the back. The beak has a large ridge on the top. Greater ani swallow small vertebrates whole, but strike caterpillars against their perch to remove its insides before swallowing.

They are the most social members of the cuckoo family, traveling in flocks and even nesting communally. The birds are widespread and stable across the Amazon area.

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