Laurel Pigeon - Ecology

Ecology

It prefers areas with steep slopes, escarpments and gullies, where it occurs in dry forest, laurel forest and Canary pine forest, as well as cultivated areas4. Nests are on the ground - in fissures, holes or small ledges, at the bases of trees, and under rocks or fallen tree trunks - in steep, rocky, shady areas with abundant shrubby vegetation4. The breeding season varies between islands, but extends from January to September, with a peak between April–June. At least on Tenerife, breeding success appears to be low, as a consequence of intense nest predation1,4.

Pigeons can breed from their first year, and nesting occurs throughout the year, although mainly from February to June. The displays are similar to those of the Common Wood Pigeon; the male climbs quickly in flight, gives a loud wing-clap, and then glides down with his wings and tail spread. The display may be repeated two or three times before the bird returns to a perch. On the ground the male performs a bowing display with his neck inflated to show off the iridescent neck patches; meanwhile, the tail is raised, fanned, then closed again. This display is usually accompanied by calling. The nest is a typical pigeon construction, a flimsy structure of twigs and grasses usually placed high in the floor of canyon walls with lots of vegetation. Nestled among the crevices in rocks, in gullies of the hills. The usual clutch has a white egg one smooth white egg. Breeding success and nest predation have effects on the two Canarian endemic pigeons, Bolle's Laurel Pigeon Columba bollii and White-tailed Laurel Pigeon Columba junoniae. Nest predation was the more important cause of nesting failure of both species (88%), but principally affecting the White-tailed Laurel Pigeon. It showed a greater predation on the ground than in trees and a lower predation in the February–March period than in June–July and September October. The abundance of predators, estimated by bait consumption, showed a similar seasonal pattern, while fruit availability decreased over time from the first to third period. Predators identified by automatic cameras showed that Black Rat Rattus rattus was the major nest predator of both pigeons. These general patterns of nest predation alfect the White-tailed Laurel Pigeon which breeds on the ground mainly during April–July, much more than Bolle's laurel Pigeon, which breeds in trees especially in February–June. All seems to indicate that rats are the key factor causing the scarcity of the White-tailed Laurel Pigeon on Tenerife.

The Laurel Pigeon is exclusively herbivorous. Nearly 60% of its diet is fruit, with most of the rest being leaves, and just 1% is flowers. The fruits of Til, Azores Laurel and Persea indica, and the fruits and leaves of Small-leaved Holly are the most frequently detected food items. Most seeds pass through the digestive system intact, apart from those of Azores Laurel, which are usually damaged. Fruit is the main component of the diet when it is readily available in autumn and winter, and leaves are consumed in spring and summer when fruits are scarce. In one study, 27% of the leaves consumed came from native trees, especially Small-leaved Holly, 61% from herbs and shrubs, and nearly 10% from introduced trees, mainly apples and peaches. This pigeon will feed in agricultural areas, where cabbage is the most commonly taken crop plant.

However, when the fruit crop of Til and Azores Laurel is poor, large numbers of pigeons may leave the forest to feed on cabbage, flowering cherries and vine shoots. Competition for food with rats can be significant in parts of the island.