page_title: Capricorn silvereye
section_title: Description
hierarchical_section_title: Capricorn silvereye / Description
context_page_description: The Capricorn silvereye, also known as the Capricorn white-eye or green-headed white-eye, is a small greenish bird in the Zosteropidae or white-eye family. It is a subspecies of the silvereye that occurs on islands off the coast of Queensland in north-eastern Australia, and which is sometimes considered to be a full species.
context_section_description: The Capricorn silvereye is the only bird endemic to the Great Barrier Reef.  It was first described by Archibald Campbell and Samuel White in The Emu from specimens collected during an expedition by the Royal Australasian Ornithologists Union to the Capricorn Group in October 1910.  They wrote:
  Zosterops were numerous, and appeared to breed on the islands, judging by a few old nests.  As at some of our more southern camps, it was delightful to listen to the subdued chorus of the birds’ sweet warbling songs at daybreak.  Regularly on Masthead they commenced to warble from 10 to 5 minutes before 5 o’clock.
  White-eyes were observed in great numbers on North-West and Tryon Islands, where, also, the nesting season had not yet commenced.  Several skins were procured – the first by Mr J.W. Mellor.
  
  From a critical examination of these skins it is at once noticeable that they are not referable to Z. caerulescens, but are more in agreement with the description of Quoy and Gaimard’s Z. westernensis.  Should further research prove them different, we venture to suggest the name Z. chlorocephalus, or Green-headed White-eye (on account of the “clean-cut” markings of that colour), the following being the general description: – Male. – Distinct ring of silvery-white round the eye, succeeded by a black line under the eye; head, mantle, upper wing coverts, and upper tail coverts bright olive-green; back grey, blending into the greenish mantle; wings and tail dark brown, the primaries and tail feathers edged with bright olive-green; chin, throat, and under tail coverts greenish-yellow; rest of the under surface grayish-blue, darkest on the chest, and approaching grayish-white on the abdomen.  Bill dark brown, the basal half of the lower mandible lighter coloured; tarsus dark grey.  Dimensions in inches: – Length, 4 ¾ [121 mm]; wing, 2 11/16 [68 mm]; bill, 7/16 [11 mm]; tail, 2 [51 mm]; tarsus, 11/16 [17 mm].
  The sexes of the Capricorn silvereye are visually indistinguishable.  The subspecies is substantially larger than Z. l. cornwalli, the taxon occupying the mainland coast opposite the Capricorn and Bunker Islands, from which it is derived, and from which it has been separated for not more than four millennia, or about 500 generations, following its colonisation of the islands.  The bird has been used as a model to investigate the hypothesis that passerines on islands have a tendency to evolve larger forms.  The lectotype is an unsexed specimen from North West Island, held by the American Museum of Natural History (AMNH 700956).
caption: Aerial view of 16-ha Heron Island from the south, site of a long-term study of the Capricorn silvereye
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