Great Spotted Woodpecker
The great spotted woodpecker is a well established Wilden Marsh and Hoo Wood resident. Its call is a sharp kik, which may be repeated as a wooden rattling krrarraarr if the bird is disturbed. The courtship call, gwig, is mostly given in the display flight. The great spotted woodpecker drums on dead trees and branches, and sometimes suitable man-made structures, like steel electricity pylons and steel fixtures on wooden poles, to maintain contact between paired adults and to advertise ownership of territory.
The hammering of woodpeckers when drumming or feeding creates great forces which are potentially damaging to the birds. In the great spotted woodpecker and most of its relatives, the hinge where the front of the skull connects with the upper mandible is folded inwards, tensioned by a muscle that braces it against the shock of the impact when the bill is hammering on hard wood. The outer layer of the upper mandible is significantly longer than the more rigid lower mandible and absorbs much of the concussive force. Skeletal adaptations and strengthening also help to absorb the shock, and narrow nostrils protect against flying debris.
The great spotted woodpecker is omnivorous. It digs beetle larvae from trees and also takes many other invertebrates including adult beetles, ants and spiders. The bird also digs for Lepidoptera larvae like Acronicta rumicis. Crustaceans, molluscs and carrion may be eaten, and bird feeders are visited for suet and domestic scraps. The nests of other cavity-nesting birds, such as tits, may be raided for their eggs and chicks; nest boxes may be similarly attacked, holes being pecked to admit entrance by the woodpecker where necessary. House martin colonies can be destroyed in repeated visits.
Great spotted woodpeckers are strongly territorial, typically occupying areas of about 5 ha (12 acres) year-round, which are defended mainly by the male, a behaviour which attracts females. Pairs are monogamous during the breeding period, but often change partners before the next season. This woodpecker occurs in all types of woodlands and is universal in its diet, being capable of extracting seeds from pine cones, insect larvae from inside trees or eggs and chicks of other birds from their nests. It breeds in holes excavated in living or dead trees, unlined apart from wood chips. The typical clutch is four to six glossy white eggs. Both parents incubate the eggs, feed the chicks and keep the nest clean. When the young fledge they are fed by the adults for about ten days, each parent taking responsibility for feeding part of the brood.
I have watched GSWs excavate deep holes into the side of living oak trees. Some produce two holes, one 150mm above another, and join them together. I watched one particular GSW complete a double hole and then decide it wasn’t quite right for some reason, and immediately moved to another oak and tried again. A green woodpecker then moved into the deserted GSW nest. When the green woodpecker and its offspring had finished with the nest, hornets took over the hole and have nested there for the last three or four years.