25+ Interesting Facts About Cuckoos

1. There are around 150 species of cuckoos. Famous birds in this medium-sized family include common cuckoos, roadrunners, anis, koels, etc.
2. Cuckoos are present in all continents except Antarctica. They prefer forests and woodlands in temperate and tropical regions.
3. Most cuckoo species live in trees, while 15 species are terrestrial. Three ground-dwelling species are brood parasites: the pheasant cuckoo, the striped cuckoo, and the pavonine cuckoo. Two species of roadrunners are also among ground cuckoos.
4. Most cuckoos have short wings and long tails. However, few migratory species have long wings, which assist them in migrating far away easily and quickly.
5. In 2020, a cuckoo bird recorded one of the longest flights by any land bird. This cuckoo covered more than 7,500 miles (12,000 km) without stopping while migrating from southern Africa to Mongolia at 60 km/h. (Source)
6. The favorite food of cuckoo birds is hairy caterpillars and other insects. Various species eat fruits, baby birds, small-sized frogs, and mammals.
7. Nearly 100 cuckoo species are brood parasites. A study shows that cuckoos and other brood-parasitic birds target birds with smaller eyes (from cuckoos and related to their body size) for egg laying. Cuckoos’ eggs are similar to host eggs, and birds with small eyes cannot differentiate between them. (Source)
8. Several cuckoo species are brood parasitic that lay eggs in hosts’ nests. Studies have proved that these parasitic cuckoos are more diet specialists than nonparasitic species. (Source)
9. Nonparasitic cuckoos build their nests in trees, bushes, or the ground to lay eggs. 

   

   Guira cuckoos are known for communal nesting and infanticide

   
   
10. The anis and Guira cuckoo apply communal nesting. Guira cuckoos sometimes kill their smaller chicks.
11. Cuckoos have unique feet compared to several other birds. They have two claws facing forward and two others in the backward direction.
12. Nonparasitic cuckoos lay white eggs, while brood parasitic cuckoos lay colorful eggs according to the color of the host’s eggs.
13. Various parasitic cuckoos lay eggs of different colors, patterns, and sizes according to the eggs of their hosts. The color of cuckoo eggs entirely depends on the mitochondrial DNA of the female cuckoo. Each species lay eggs of a single type and target the host accordingly. (Source)
14. Various species lay two to eight eggs in a clutch. The incubation period is from 9 to 14 days.
15. Parasitic cuckoo eggs have thick eggshells with more calcium than eggs of other cuckoos. The purpose of this thickness is to reduce the risk of cracking when dropping them into the host’s nest and provide protection against puncture by the host. (Source)
16. The cuckoo egg hatches earlier than the host’s egg, which plays a vital role in its survival. According to a study, it happens because the female cuckoo releases the egg into the nest after keeping it inside her body for 24 hours. The idea of internal incubation initially appeared in 1802 and later proved in 2010. (Source)
17. Most cuckoo species are monogamous, but some species of coucal practice polyandry.
18. Channel-billed cuckoo is the largest species, reaching two feet (24 inches) in length and attaining 1.3 pounds. The smallest species is the little bronze cuckoo, which can acquire 6 inches in length and nearly half an ounce in weight.
19. Host birds try to protect their nests from cuckoos by attacking the birds and throwing their eggs after recognizing them. Laying eggs is more difficult for cuckoos with multiple hosts due to their eggs of different colors and sizes. In this case, the female cuckoo will lay average eggs that do not resemble any of the host eggs but match all or most of them. (Source)
20. Parasitic cuckoos throw a host’s egg to make space for its egg. If the host rejects the cuckoo’s egg, some cuckoo species may destroy the entire nestlings of the host.
21. Cuckoos are named after the calls of male birds. The females have a “bubbling chuckle” like call.
22. Along with mimicking the color and size of eggs, cuckoos also take other measures to ensure the laying and survival of their eggs in the host’s nest. These parasitic birds lay eggs at the right time of the day and time of the season according to the host’s egg laying.
23. Many parasite cuckoo chicks kill the babies of their hosts. However, great spotted cuckoos share the nest with chicks of carrion crows and protect them from predators through their smelly fluid, excreted from cloacae. (Source)
24. Research proves that several cuckoo species mimic hawks and other birds of prey to lay eggs in the host’s nests. These birds mimic the feathers of raptors in their locations to frighten away the host birds. This behavior has been seen in common cuckoos, Eurasian sparrowhawks, African cuckoo-hawks, and other cuckoo species. (Source)
25. Most parasitic cuckoos lay one egg per nest. However, a few species lay multiple eggs in a single host nest.
26. Snakes and raccoons are the main threats to cuckoo eggs. Birds of prey are the primary predators of adult cuckoos.
27. Cuckoos are solitary birds and rarely mix with others except during the breeding season. Most species are diurnal.