20 November 1996        5c, 10c, 20c, 90c, + 2 x $2.00             Mint and CTO        $5.25
                                                                                                              FDC                       $5.75

        Release Date:                  20 November 1996
        Tablet Values:                 5c, 10c, 20c, 90c, + 2 x $2.00
        Artists:                            4 x WWF Birds - Andrew Robinson
                                               2 x Birds           - Norman Arlott
        Printer:                            Walsall Security Printers Ltd
        Process:                          Lithography
        Paper:                             CA Spiral Watermark
        Stamp Size:                     48.26 x 31.75 mm
        Perforation Gauge:           13.7 holes per 20 mm
        Pane Format:                   50 (2 x 25)
        Mint and CTO:                $5.25
        First Day Cover:              $5.75

The World Wide Fund for Nature stamps featured in this issue, colourfully depict the four species of land bird found on Henderson Island.  Henderson Island is designated a World Heritage Site.  Its remote location and relatively inaccessible coastline and terrain have ensured minimal human interference.  It is likely that the introduction of the Polynesian rat (Rattus Exulaus) perhaps as early as the 8th century ADC led to the extinction of other species.
 
The Henderson Island Reed Warbler (Acrocephalus vaughani taiti) is an identifiable sub-species of the Pitcairn Warbler (Acrocephalus vaughani vaughani), Pitcairn's only surviving land bird.  Known locally as the sparrow, this warbler is quick enough to avoid the wild cats of Pitcairn.

The 10c stamp shows our Stephen's Lorikeet (Vini stepheni).  Stephen's Lory feeds on nectar, pollen and fruits, the main source of nectar being the flowers of Scaevola sericea and Timonius polygamus.  Our Lory has a substantial population on Henderson Island.  The four other members of genus Vini in the South Pacific, have had their populations reduced as a result of changes in their habitats and the introduction of predators such as cats and hawks.

The Henderson Island Rail (Porzana atra) is most closely related and a likely descendant of the Spotless Crake (Porzana tabuensis) found across the Pacific and closest to Henderson, on Oeno Island.  Although similar in colour and plumage, the Rail has about twice the body mass but much the same skeletal size and wing size as the Spotless Crake.  These features render the Henderson Island Rail flightless.  In March 1992, scientists of the Sir Peter Scott Commemorative Expedition to the Pitcairn Islands estimated the Rail population at just over 6,200 adult birds.  Although these birds co-exist alongside the Polynesian rat, it is likely there are egg losses to these predators.  Henderson Island Rails are aggressive towards rats and have been frequently seen chasing them.  They feed on insects, spiders, caterpillars, snails and even the eggs of skinks which may be attached to the underside of fallen Pandanus leaves.  Pitcairners know the Rail as the Chicken Bird.
 
The Fruit Dove (Ptilinopus insularis) featured on the 90c stamp, is a colourful bird which for the last 400 years has been the sole frugivore on Henderson.  Before the Polynesian settlement of Henderson between 800 and 1600 AD, two other dove species, a Gallicolumba ground-dove and a Ducula pigeon coexisted with the Fruit Dove.  The cause of their demise cannot be certain but may relate to the Polynesian occupation.  The population of the Fruit Dove is estimated at around 3,200 birds and it is suggested that the availability of fruit is the control factor in terms of population size.  Most types of ripe fruit are eaten according to seasonal availability by this bird, known locally as the Wood Pigeon.

The two additional birds in this issue, the Masked Booby (Sula dactylatra) and the Fairy Tern (Gygis alba pacifica) are both sea birds and breed on Ducie, Henderson and Oeno Islands.  The Fairy Tern also breeds on Pitcairn, laying its eggs on the bare branches of trees.

In presenting this background information, we acknowledge the work of members of the Sir Peter Scott Commemorative Expedition to the Pitcairn Islands, particularly T.G. Benton, T. Spencer, M. de L Brook and P.J. Jones.