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Material contained herewith may not be used without the prior written permission of FAUNA Paraguay.
Photographs on this web-site were taken by Paul Smith, Hemme Batjes, Regis Nossent,
Alberto Esquivel, Arne Lesterhuis, José Luis Cartes, Rebecca Zarza and Hugo del Castillo and are used with their permission.
CUCULIDAE - CUCKOOS
Thirteen species in this global family reach Paraguay. Cuckoos can be split into six subfamilies, three of which are represented in Paraguay and their characteristics are discussed below. The oldest known fossil cuckoos date from the Lower Oligocene, though fossils with cuckoo-like characteristics have been found in the Eocene. The modern cuckoo assemblage is diverse in form, but DNA studies have revelaed them to have no close living relatives.
Cuckoos are medium-sized birds with slender body form. They have soft, loose-fitting plumage and zygodactyl feet - two toes face forwards and two backwards. Typically the legs are short with scutellate tarsi, and the tail is long, in many cases greater than body length. Long eyelashes and a musty smell are characteristic of some species. Cuckoos have 10 primaries, 9-13 secondaries and, with the exception of Crotophaga, 10 retrices. The wing is eutaxic, there is a secondary feather for each secondary covert. Feather aftershafts are small or absent. A naked, bi-lobed oil gland is present.
Many of the skeletal characteristics of cuckoos are plesiomorphic (primtive) and contain numerous characters retained from their ancestors. Cuckoos have a holorhinal nasal septum, small vomer, a desmognathous palate, two bony canals in the hypotarsus and 14 cervical vertebrae. They lack a basipterygoid process. Skeletal characteristics do not necessarily correspond well with the current subfamilial treatment.
Breeding systems vary widely in this family and the stereotypical "brood parasite" cuckoo is by no means the norm, at least amongst New World cuckoos. Young are altricial and downy feathers are limited to the apteria. Nesting cuckoos are socially monogamous, even in co-operative breeding species where pair bonds are formed within groups. In brood parasitic species the young are intolerant of host chicks and kill them shortly after hatching with the hooked tip of the upper mandible.
Subfamily Coccyzinae "New World Cuckoos" (Coccyzus and Piaya)
Build their own, saucer-shaped nests. Silhouette hawk-like with pointed wings and graduated tail. Strong, direct flight. Some species are migrant. Fairly long, slightly downcurved upper mandible. Arboreal insect eaters, particularly caterpilars. Young with contrasting paillae on the inside of the mouth. Little or no sexual size difference.
Subfamily Neomorphinae "Ground Cuckoos" (Dromococcyx and Tapera)
Long-legged and long-tailed. Crested and cryptically-plumaged. Three Paraguayan representatives are the only brood parasitic members of this subfamily. Semi-terrestrial ground feeders. Extremely secretive behaviour. Males slightly larger than females.
Subfamily Crotophaginae "Social Cuckoos" (Crotophaga and Guira)
Has in the past been treated as a separate family Crotophagidae. Social, semi-terrestrial in behaviour. Co-operative breeders, nestlings with pink gapes with white markings. Open country species. Movements clumsy and weak flap and glide flight. Crotophaga has dense, smooth, glossy plumage and 8 retrices. The bill is deep and laterally compressed. Females slightly larger than males.
REFERENCES
Campbell B & Lack E 1985 - A Dictionary of Birds - T & AD Poyser.
Payne RB 1997 - Cuculidae Handbook of the Birds of the World Volume 4 - Lynx Ediciones.
