Grosbec core breaker, big billed passerine


The core-breaker grosbec does not owe its name to chance. The sparrow in the body compact has sufficient beak and mandibles mighty for breaking pits of cherries and olives. Portrait of a stocky but strong bird.

Identity card of the core breaker Grosbec

The core-breaker Grosbec is a species of bird belonging to the order Passeriformes and to the family of Finches (finches, goldfinch …), of which it is the most imposing representing. The sparrow measures 16 to 18 cm and weighs between 48 and 62 gr. It is found on all continents, with the exception of the‘Oceania.

Colorful plumage for the stone-busting grosbec

The core breaker grosbec is distinguished by a profile stocky marked by its conical beak, broad head, lack of neck and short tail. The breeding male is very colored. The head, crown, neck and cheeks are colored orange-brown, with the back of the crown light brown. The blue bill is surrounded by a black circle, narrow at the forehead but wider around the eye and the bib. The bird wears a dark brown coat and the pale buff rump ends in a white stripe. The upperwing shows a white spot, the flight feathers are black while the deep blue primaries display stunning spiked ends. arrow shiny dark blue. Lower abdomen and undertail coverts are white. The eyes are tinged with a pinkish brown and the legs pink. The adult female is identical male but with more plumage dull.

Grosbec core breaker: a force of nature

The most obvious morphological characteristic of the species is its imposing beak. Behind this attribute hides a powerful musculature mandibular, explaining the large head of the bird. The sparrow’s jaws exert such force that they can break cores. It is estimated that more than 45kg the pressure exerted by its mandibles. On the other hand, the interior of its beak has raspy streaks which help him to wedge the food well before breaking it. The stone-breaker grosbec can thus open the hard husks of fruit (cherries, olives) to eat the seeds or almonds that are there.

The core breaker Grosbec, a forest species

The core breaker Grosbec lives in westernEurope as far as temperate Asia via central Siberia. The European population is sedentary or partial migratory while the Russian and Asian numbers migrate south in winter. In France, during the breeding season, the bird frequents the north-eastern quarter, the northern Alps and the vast forests of the center of the country. The Stone Cracker Grosbeak frequents mainly the forests of sheets, mixed or coniferous. Little by little, its habitat has extended to orchards, parks and gardens, depending on the presence of the seeds on which it feeds. The species occupies all vegetation strata, from soil to canopy, depending on the season and the resources available.

Samaras for the core breaker Grosbec

The core-breaker grosbec mainly consumes winged seeds (samaras) produced by hornbeams, maples, lime trees, beeches or ash trees, which it takes from the ground or directly from the trees. In spring, it can also feed on buds, young shoots of trees and theninsects in summer. In the fall, berries of blackthorn, hawthorn, rowan, dogwood and holly complete its menu. In winter, he does not disdain to peck a few sunflower seeds made available on the feeders. As seen previously, the bird is also able to open the pits of cherries or olives to eat their contents.

The stone-busting grosbec, a fierce bird

Shy and discreet, the core breaker Grosbec is difficult to observe. It flies above the canopy and often perches high in trees, hidden by foliage dense forests. A noise will make it fly higher and it will not come back down until the place is safe. It is in winter, on the posts of feeding, that he shows himself more willingly but always furtively. During the breeding season, the stone-breaker Grosbec is fairly territorial and aggressive. However, he agrees to nest with a few handpicked mating pairs.

The parades of the amorous grosbec

The breeding season begins towards the end of April and the species monogamous usually only raises one brood per year. In the mating season, the male sings to attract a female and then begins to parading, rocking right and left while screaming. It inflates the feathers of the head and the chest, spreads its tail and performs bows with the wings lowered to expose the iridescent blue flight feathers. The male also offers offerings of food directly into its partner’s beak.

Young core-breaker grosbecs: farewell parents!

The male chooses the nesting site, usually in the fork of a leafy tree more than 3 m in height. The nest forms a chopped off made up of twigs, grasses and lichens then garnished with rootlets. The female deposits there 3-5 eggs pale blue or greenish, slightly spotted with black. She broods them for 9 to 14 days while the male takes care of providing her with food. The chicks are fed by their parents with a mixture of insects and seeds regurgitated. They leave the nest when they are 12 to 13 days old, but remain under the addiction adults for another fortnight. The young people emancipate themselves after a month and leave their families to join other groups.

No threat to the core breaker Grosbec

Adults and young stone-breaking Grosbecs are the preys usual for domestic cats and some birds of prey such as the northern goshawk and the European hawk. Classified in category Least concern by the International Union for the Conservation of Nature (IUCN), the species is not considered threatened. Without being abundant, the sparrow remains common in our forests. The longevity of the core breaker grosbec is 10 years.

Photo credit: Martin Mecnarowski