Chordates • Earth.com

Razorbill

(Alca torda)

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Description

The razorbill has white underparts and a black head,neck,back and feet during breeding season.A thin white line also extends from the eyes to the end of the bill.Its head is darker than that of a common murre.During the nonbreeding season,the throat and face behind the eye become white,and the white line on the face becomes less prominent.The thick black bill has a blunt end.It is large for an alcid and its mean weight ranges from 505 to 890 g (17.8 to 31.4 oz).The female and male adults are very much alike,having only small differences such as wing length.The wing length of adult males ranges from 201–216 mm (7.9–8.5 in) while that of females ranges from 201 to 213 mm (7.9 to 8.4 in).This species has a horizontal stance and the tail feathers are slightly longer in the center in comparison to other alcids.This makes the razorbill have a distinctly long tail which is not common for an auk.Their mating system is female-enforced monogamy;the razorbill chooses one partner for life.It nests in open or hidden crevices among cliffs and boulders.It is a colonial breeder and only comes to land to breed.The annual survival rate of the razorbill is between 89-95%.Though the razorbill's average lifespan is roughly 13 years,a bird ringed in the UK in 1967 has survived for at least 41 years — a record for the species.

Taxonomic tree:

Domain:
Kingdom: Animalia
Phylum:
Class: Aves
Order:Charadriiformes
Family:Alcidae
Genus:Alca
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