NORTHERN GANNET

Morus bassanus

English: Northern Gannet.
German: Basstölpel.
French: Fou de Bassan.

Clasificación/Clasification

Order: Suliformes.
Family: Sulidae.

Longitud/Length

87-100 cm.

Envergadura/Wingspan

165-180 cm.

Aves relacionadas/Similar species

The Northern Gannet cannot be confused with any other species in the Iberian Peninsula.

Sexo/Sexing

In terms of plumage, there is no sexual dimorphism in this species, although generally, the male is slightly larger than the female.

Edad/Ageing

It is possible to recognize 5 different ages:

Juvenile specimen: these individuals have a completely brown plumage. The secondary coverts (greater, median and lesser) show a white brush on their tip. This same detail is observed in all the feathers of the head, throat, scapulas and back. The rectrices are the same brown tones and show the same white brush, only it is appreciable for a very short time, due to the great wear that these feathers suffer. The lower parts, the chest, belly and undertail coverts are dyed in light tones.

1st winter specimen: they still maintain almost all the plumage from the previous generation. They begin to lighten some areas (throat and nape) without reaching a white tone. The undertail coverts begin their molt in the innermost area (axillars).

2nd winter specimen: at this age, some areas appear completely tinted white: the lesser coverts (the innermost and closest to the body), the head, nape, throat and chest. Several central secondary coverts are still retained from the juvenile generation, showing great wear. Some uppertail coverts spotted with white. The rectrices are still of the juvenile type.

3rd winter specimen: they have an intermediate plumage and there is a great overlap between individuals.

4th winter specimen: they show a plumage quite close to the adult plumage. These specimens retain some secondary coverts, greater coverts and some – or most – of the rectrices (even some specimens only retain the central pair). The plumage of the head, nape and throat begins to show yellowish tinges already very close to the adult plumage.

Adult specimen: These specimens have a general plumage color of white, with the exception of the primaries that are dyed a dark brown (in some specimens it can even extend to the first secondary coverts). The plumage of the head, nape and throat with yellowish tinges. The rest of the body has a white plumage, including the undertail coverts, chest, mantle and rectrices.

Muda/Moult

Configuración del plumaje/Plumage configuration

Primaries: 10 per wing.
Secundaries: 27-30 per wing.
Rectrices: 12.

Observaciones/Remarks

La obtención de este material ha sido posible gracias al permiso necesario de la Junta de Andalucía.

AUTORIZACIÓN DE LA DIRECTORA GENERAL DE MEDIO NATURAL, BIODIVERSIDAD Y ESPACIOS PROTEGIDOS DE LA CONSEJERÍA DE AGRICULTURA, GANADERÍA, PESCA Y DESARROLLO SOSTENIBLE DE LA JUNTA DE ANDALUCÍA, PARA LA CESIÓN DE MUESTRAS BIOLÓGICAS DE ESPECIES DE FAUNA (ARTÍCULO 9 DE LA LEY 8/2003, DE 28 DE OCTUBRE, DE LA FLORA Y LA FAUNA SILVESTRES).

Medidas/Measures

Biometría/Biometrics

Juvenile specimen:
Beak tip to pupil center: 119mm
Tarsus: 54mm

Juvenile specimen

alcatraz atlántico 10

alcatraz atlántico 11

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1.- Right wing primaries. 2.- Primaries. 3.- Details of the outer and inner vanes of the outer primaries. 4.- Details of the outer and inner vanes of the inner primaries. 5.- Details of the tip of the outer primaries. 6.- Details of the tip of the inner primaries. 7.- Details of the vanes of the primaries. 8.- Details of the calamus of the primaries. 9.- Details of the calamus of the primaries. 10.- Details of the primaries. 11.- Secondaries (S1-S10). 12.- Secondaries (S11-S20). 13.- Secondaries (S21-S30). 14.- Secondaries and tertials of the right wing. 15.- Details of the outer and inner vanes of the secondaries. 16.- Details of the outer vanes of the secondaries. 17.- Details of the tip of the secondaries. 18.- Details of the secondaries. 19.- Details of the calamus of the secondaries. 20.- Details of the secondaries. 21.- Details of the secondaries. 22.- Details of the tertials. 23.- Primaries, secondaries and Tertials of the right wing. 24.- Primaries, secondaries and tertials of the right wing. 25.- Primaries, secondaries, and tertials. Primary coverts and greater coverts. 26.- Primaries, secondaries, Tertials. Primary and secondary coverts (G, M, and L). Alulas. 27.- Details of the primary coverts. 28.- Details of the primary coverts. 29.- Details of the primary coverts. 30.- Details of the greater coverts. 31.- Details of the secondary coverts. 32.- Tertiary coverts. 33.- Details of the secondary coverts. 34.- Rectrices. 35.- Details of the vanes of the rectrices. 36.- Rectrices. 37.- Details of the rachis of the rectrices. 38.- Details of the tip of the rectrices. 39.- Details of the tip of the central rectrices. 40.- Rectrices + uppertail coverts. 41.- Details of the uppertail coverts. 42.- Uppertail coverts. 43.- Rectrices + undertail coverts. 44.- Details of the undertail coverts. 45.- Primary infra-coverts. 46.- Secondary infra-coverts. 47.- Right axillary feathers. 48.- Primary coverts. 49.- Secondary Coverts. 50.- Alulas. 51.- Assembly of the right scapula. 52.- Scapula feathers. 53.- Assembly of the right flank. 54.- Flank feathers. 55.- Assembly and feathers of the back. 56.- Assembly and feathers of the belly. 57.- Assembly and feathers of the nape. 58.- Assembly of the crown. 59.- Assembly of the crown. 60.- Crown feathers.

NORTHERN GANNET

Medidas/Measures

Juvenile specimen

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