Great Spotted Woodpecker - Ecology

Ecology

It is an inhabitant of woodlands and parks, depending for food and nesting sites upon old trees. Its actions are jerky, and it hops rather than climbs, leaping forward with one foot just in advance of the other. When a space is crossed the flight is easy and undulating.

The food mainly consists of insects and grubs but also seeds, fruit, scraps, eggs, chicks and small rodents. The woodpecker usually alights on the trunk, working upwards, from side to side, but sometimes will perch in passerine style, when it sits well upright. During the ascent it taps the bark, breaking off fragments, but often extracts its prey from crevices with the tip of its sticky tongue. Beechmast, acorns, nuts and berries are eaten when animal food is scarce.

The nesting hole, neat and round, is bored in soft or decaying wood horizontally for a few inches, then perpendicularly down. At the bottom of a shaft, usually from six to twelve inches in depth, a small chamber is excavated and lined with wood chips. This woodpecker shows no marked preference for particular tree taxa, building its nest in gymnosperms and angiosperms alike.

In Japanese forests for example, nests were observed in Fagales (Grey Alder, Alnus hirsuta ssp. incana; Japanese White Birch, Betula platyphylla; Japanese Hop-hornbeam, Ostrya japonica), Lamiales (Japanese Tree Lilac, Syringa reticulata), Malvales (Japanese Lime, Tilia japonica), Malpighiales (willows, Salix sp.), Pinales (Japanese Larch, Larix kaempferi), Rosales (Sargent's Cherry, Prunus sargentii) and Sapindales (Usugumo Maple, Acer pictum subsp. mono– Painted Maple). Mongolian Oak (Quercus mongolica, Fagales) and Prickly Castor-oil Tree (Kalopanax pictus, Apiales) were rarely if ever used for nesting however.

Nesting trees chosen by this woodpecker almost invariably have soft heartwood and tough sapwood, often due to parasites or diseases that weaken the heartwood only. It is unknown how D. major finds suitable trees, though it is entirely possible that they do so by drumming, making use of the different speed of sound in materials with differing elastic modulus and density. Tree species which are rarely or never used for nesting might simply not have wood with the required properties.

The creamy-white eggs, five to seven in number, are laid in the second half of May. The young cluster at the mouth of the hole and keep a continuous chatter when the parents are feeding them, but when alarmed slip back into the hole. The nest hole is rarely used again, but not infrequently other holes are bored in the same tree.