The greater ani and smooth-billed ani are two similar looking bird species found in the Americas. At a glance, they can appear nearly identical. However, there are some key differences between the two species that allow birders to distinguish them.
Range and Habitat
The greater ani has a more extensive range than the smooth-billed ani. The greater ani is found from southern Florida, Mexico and the Caribbean south to Argentina. The smooth-billed ani has a more limited range from eastern Mexico south to northwestern Peru and central Brazil.
Both species occupy open or semi-open habitats including grasslands, savannas, cultivated areas, pastures, and swamps. However, the greater ani is more likely to inhabit drier, more open areas while the smooth-billed ani prefers wetter, dense vegetation. This difference in preferred habitat can aid in identification.
Size and Shape
The greater ani is a larger bird than the smooth-billed ani. The greater ani measures around 20 inches (51 cm) long with a wingspan of 12.6–13.8 inches (32–35 cm). It weighs approximately 6.3–7.7 oz (180–220 g). The smooth-billed ani is smaller at 15.7–18.1 inches (40–46 cm) in length with a wingspan of 9.8–10.6 inches (25–27 cm). It weighs 3.5–4.2 oz (100–120 g).
Both species have long tails that make up around half their total body length. The greater ani’s tail is noticeably longer than the smooth-billed ani’s. The greater ani’s tail is around 9.8-11.8 inches (25-30 cm) while the smooth-billed ani’s tail is 6.7-8.3 inches (17-21 cm).
In terms of body shape, the greater ani has a slightly thinner, more streamlined profile. The smooth-billed ani looks bulkier and more pot-bellied in comparison.
Bill Shape
As their names suggest, the bill shape differs between these two species. The greater ani has a long, gradually downcurved bill that tapers to a point. The tip of the greater ani’s bill is sharply pointed.
In contrast, the smooth-billed ani has a shorter, stouter bill that is rounded at the tip giving it a smooth outline. The smooth-billed ani’s bill lacks the sharp point of the greater ani.
| Species | Bill Shape |
|---|---|
| Greater Ani | Long, tapered, sharply pointed |
| Smooth-billed Ani | Shorter, stouter, rounded tip |
Plumage
The plumage of these two ani species is very similar. Both have mainly black plumage with glossy blue highlights on the wings, tail, and head. The greater ani sometimes shows more purple-blue iridescence compared to the smooth-billed ani.
The most noticeable plumage difference is the white marking at the tip of the tail. On the greater ani, the white tail tip is very small, usually less than 0.4 inches (1 cm). The smooth-billed ani has a more extensive white tail tip band of 0.8-1.2 inches (2-3 cm).
The bare skin around the eye is also distinctive. The greater ani has blue skin around the eye. The smooth-billed ani has brown or reddish-brown bare skin around the eye.
Plumage Comparison
| Feature | Greater Ani | Smooth-billed Ani |
|---|---|---|
| Body Plumage | Black with blue iridescence | Black with blue iridescence |
| White Tail Tip | Very small, < 1 cm | Large, 2-3 cm |
| Bare Skin by Eye | Blue | Brown or reddish-brown |
Calls
The calls of the greater ani and smooth-billed ani differ significantly. This is often the easiest way to distinguish these otherwise similar looking birds.
The greater ani has a very loud, shrill, screaming call. It makes a noisy series of piercing shrieks described as “pi-pi-pi-pi-pi-piu”.
The smooth-billed ani’s call is described as a whinnying “an-teeee” or groaning “uuuuuh”. The tone is gurgling and guttural, very unlike the strident greater ani.
Below are examples of the call of each species:
Greater Ani Call
Smooth-billed Ani Call
Behavior
Both the greater ani and the smooth-billed ani are social birds that travel and roost in flocks. However, group sizes differ between the species.
Greater anis form large flocks of up to 100 or more birds. Groups often splinter off during the day while foraging then reassemble in the evening. Smooth-billed anis form smaller groups of around 10-30 individuals that remain fairly constant throughout the day.
Breeding
The breeding behavior of these species also varies.
Greater anis breed colonially with multiple nests clustered closely together in one tree, often with communal perches and sentry points. Smooth-billed anis nest singly or in loose colonies with nests further spaced apart.
Greater anis build large communal stick nests that are reused and added to over successive years. Smooth-billed anis construct a new cup-shaped nest out of twigs each breeding season.
Diet
Both the greater ani and smooth-billed ani are omnivorous, feeding on a combination of insects, small vertebrates, seeds, and fruit. However, they differ in their preferred food sources.
Greater anis feed more heavily on insects like grasshoppers, cicadas, beetles and caterpillars. Smooth-billed anis consume a higher proportion of vegetable matter including corn, grains, and berries.
The greater ani’s slender pointed bill is adapted for catching insects. The smooth-billed ani’s shorter bill allows it to more efficiently crack hard seeds.
Taxonomy
The greater ani (Crotophaga major) and smooth-billed ani (Crotophaga ani) were previously considered to be a single species – the ani. However, in 1945 the American Ornithologists’ Union determined they were separate based on differences in appearance, voice, behavior, and habitat.
Some authorities still lump the two as a superspecies, but most now recognize them as distinct. They are the only two members of the genus Crotophaga in the cuckoo family (Cuculidae).
Conclusion
In summary, while the greater ani and smooth-billed ani appear nearly identical at first glance, a closer look reveals several differences in size, bill shape, plumage, voice, behavior, and preferred habitat and diet. The two species occupy overlapping ranges in South and Central America, but can reliably be distinguished through careful observation.
The key identification points are:
- The greater ani is larger with a longer, more tapered tail
- The greater ani has a slender, pointed bill; the smooth-billed ani’s bill is shorter and rounded
- The greater ani has a tiny white tail tip; the smooth-billed has a broad white tail band
- The loud, shrieking call of the greater ani contrasts with the groaning call of the smooth-billed
- Greater anis occur in larger flocks and build communal nests unlike the smooth-billed
So in summary, while these cuckoo species may appear identical at first glance, experienced birders can confidently differentiate the greater and smooth-billed anis through careful observation of size, structure, plumage, voice, and behavior.
