Great Cuckoo-Dove

The Great Cuckoo-Dove is one of the most striking pigeons of the New Guinea region, a large, slender bird whose enormously long, graduated tail gives it an unmistakable, almost falcon-like profile as it sweeps across a forest clearing. Pale silvery grey on the head and underparts and rich chestnut above, it perches boldly on bare snags and exposed branches where few other forest pigeons choose to sit in the open, making it one of the more watchable members of a notoriously shy family.

It is the largest of the cuckoo-doves, and its scientific name honors the Dutch botanist Caspar Reinwardt, founder of the botanical gardens at Bogor. Widespread across mainland New Guinea, the Moluccas, and many satellite islands, it remains common enough to be listed as Least Concern. Birders traveling through the region often meet it at forest edges and along ridgelines, where its bounding display flights and deep, carrying coo announce its presence before the bird itself comes into view.

This is a big, long-tailed pigeon that is hard to confuse with anything else in its range. The combination of a whitish or pale blue-grey head and underparts, warm chestnut upperparts, blackish outer wings, and a remarkably long, strongly graduated tail creates a two-toned bird with a distinctive silhouette both perched and in flight. In good light the pale eye set in colored bare skin gives the face an alert, staring expression. Size alone separates it from most sympatric pigeons, and the long tail is diagnostic.

Male vs. female

The sexes are broadly alike and cannot be told apart with confidence in the field. Males average marginally larger and may show slightly more richly saturated chestnut on the upperparts, but the overlap is wide and any single bird is effectively unsexable by plumage alone. Unlike many fruit-doves and imperial-pigeons of the region, the Great Cuckoo-Dove does not carry bright sexual ornamentation, so a perched pair typically looks like two nearly identical birds.

Juveniles

Juveniles are duller and more heavily marked than adults. Young birds show buff or rufous fringing to the feathers of the upperparts and wing coverts, giving a scaled, less uniform appearance, and the grey of the head and underparts is washed with brown and looks less clean. The bare facial skin and eye color are duller than in adults. As with most pigeons the immature plumage is held only briefly before a molt into adult-like feathering, so scaly-looking young are seen far less often than crisp adults.

The Great Cuckoo-Dove gives a deep, resonant cooing that carries well through humid forest. A commonly heard call is a loud, emphatic note repeated in a rising or accelerating series, and displaying birds may combine these coos with the sound of the wings. Vocalizations are most frequent in the early morning and are often the first clue to the bird's presence, as it tends to call from an exposed perch or the canopy before it is seen.

The species is best known for a spectacular aerial display: a bird launches from a high perch, rises steeply on rapidly beating wings, then sets its wings and glides or plunges back down in a bounding, roller-coaster arc, sometimes calling as it goes. These display flights over the forest canopy and clearings are one of the most reliable ways to detect the bird from a distance.

The Great Cuckoo-Dove ranges across the New Guinea region and into eastern Wallacea. It occurs nearly throughout mainland New Guinea, absent mainly from the dry, treeless Trans-Fly lowlands in the south, and extends onto a long list of satellite islands including Waigeo, Salawati, Batanta, and Misool in the western Papuan islands, plus Yapen, Biak, Goodenough, and Fergusson. Westward it reaches the northern and central Moluccas, where island populations are sometimes treated as distinct subspecies.

Its preferred habitat is primary forest and its edges, together with forest clearings, regrowth, and the margins of gardens and cultivation carved out of the forest. It ranges from the lowlands well up into the hills and lower montane zone, in places recorded above 2,000 meters. Rather than skulking deep in the interior, it favors situations with open airspace, ridgelines, edges, and gaps, where its long-tailed silhouette and bounding flight are shown to advantage.

Like other cuckoo-doves, the Great Cuckoo-Dove is primarily a fruit and seed eater that forages in the forest canopy and mid-story. It works through fruiting trees and vines, plucking berries and small fruits while perched or clambering acrobatically among slender branches, its long tail helping it balance as it reaches for food at the tips of twigs.

It shows a notable association with plants in the family Araliaceae, especially climbing and shrubby species in the genus Heptapleurum (formerly placed in Schefflera), whose small fruits appear to be an important food. By swallowing fruit whole and later depositing the seeds elsewhere, the bird acts as a seed disperser for a range of forest plants, a role shared by many of New Guinea's pigeons and doves.

The nest follows the standard pigeon pattern: a flimsy, flattish platform of sticks, twigs, moss, rootlets, and ferns, built on a branch or in a tangle of vegetation. Into this the female lays a single white egg, the usual clutch for a cuckoo-dove, and both parents share incubation and the feeding of the chick on crop milk, as is typical throughout the pigeon family.

On New Guinea breeding appears to be possible in almost any month, with records of nests, eggs, and dependent young spread across much of the year and some evidence of a peak late in the calendar. This extended, aseasonal breeding is common among tropical forest pigeons whose fruit food supply is available year-round rather than concentrated in a single short season.

This is a wild tropical forest pigeon, not a bird you can draw to a garden, so the practical question is where and how to see one. The good news is that the Great Cuckoo-Dove is widespread and reasonably conspicuous, and a birding trip to New Guinea or the Moluccas stands a fair chance of encountering it.

• Look in New Guinea and its satellite islands, including well-birded areas such as the Arfak Mountains, Varirata National Park near Port Moresby, and the western Papuan islands like Waigeo (a stop on many Raja Ampat birding routes).
• Focus on forest edges, clearings, and ridgelines rather than closed interior forest, as the bird favors situations with open airspace where it perches in the open and displays.
• Search the early morning, when birds are most vocal and most likely to be perched on exposed snags or making display flights over the canopy.
• Watch for the bounding display flight, a steep rise followed by a set-winged glide, which often reveals the bird at a distance before you can see plumage detail.
• Scan fruiting trees and Araliaceae tangles, where feeding birds clamber among the branches, and check exposed perches along forest tracks and roadside clearings.
• In the northern and central Moluccas, look for the regional forms on islands such as Halmahera, where the species also occurs at forest edges and in hill forest.

• Pied Cuckoo-Dove: A related long-tailed pigeon of New Guinea's mountains, boldly black and white rather than grey and chestnut
• Brown Cuckoo-Dove: A long-tailed cuckoo-dove of Australia and New Guinea, uniformly warm brown and lacking the grey head