Passenger Pigeon
Some remarks on this catalogue of extinct and threatened birds
This ZMA catalogue not only includes details on extinct and threatened birds, but also data on near-threatened ones as far as listed in BirdLife International (2000). Though these near-threatened birds are at lower risk than threatened ones, they are included in the list because in the worst scenario the near-threatened birds of the present are the threatened ones of the near-future, and publishing data on them may help in their conservation.
Further, this catalogue lists also some extinct and threatened subspecies, a category not included in BirdLife International (2000). The reason to neglect them in the latter is quite obvious: many widespread species have populations on small islands which are taxonomically separable as subspecies, and many of these survive in such small numbers or in such small patches of habitat that they would qualify as threatened. Species widespread on (e.g.) the Moluccan Islands have separate subspecies on each island; though the species as a whole is not threatened, the population on each of the islands may be small and vulnerable and should qualify for inclusion in the Red Data Book. The number of threatened and extinct subspecies would rise the number of taxa to be listed to a hard-to-handle thousands when they were included.
However, taxonomists do not agree on the global number of bird species recognised, as this depends on the species-concept they use. In the Biological Species Concept (BSC), long in use in the 2nd half of the 20th century, about 9800 bird species were separated. Since the use of DNA-sequencing in taxonomy, it is quite clear that a fair number of the species recognised under the BSC are no natural units, and that superficial resemblance and range exclusion is no reason to combine two taxa in a single species. New species concepts have been developed, and it is clear now that if one wants to build a tree of relationships one should start from a base in which a single diagnosable taxon is the unit rather than a polytypic species. Subspecies can then no longer be recognised, and the total number of bird species would rise to an estimated 25,000. For this list, this latter species concept is not followed, but a number of well-differentiated threatened and extinct taxa have been included: though still listed as subspecies in our catalogue they are likely to be raised to species-level in the near-future, even by those scientist propagating the BSC.
The heading of each species lists the Scientific and English names (from BirdLife International 2000, 2001), as well as Dutch names from Walters (1997). It is followed by a short survey on the distribution, population size, and threats, based mainly on the books of BirdLife International (2000, 2001) and the not-yet-completed Del Hoyo et al. (8 volumes 1992-2004), added to give some background information on the species involved. Data on extinct birds were derived from Greenway (1967), Fuller (1987), and BirdLife International (2000). Though the information presented is a shortened version of the info given by these highly valuable sources, they are not acknowledged in the running texts. Any misinterpretations of the sources are my responsibility. For fuller and trustworthier data, the original books should be consulted. Occasionally some newer data on numbers or threats are added from recent literature (which is acknowledged). The paragraph also includes the subspecies recognised (if any). The list of specimens in the ZMA follows, arranged according to collection number, but numbers with (largely) similar data are often combined under a single entrance. Often, the species text ends with "Remarks", in which comments on the subspecies represented are given, or on the taxonomy followed, or on characters of the species, or on specimens no longer present in the collection, or a critique on its status as given in BirdLife International (2000).
The data provided for each specimen are those as given on the newest attached label. Some data given were not provided on the original label, and these are attached in square brackets. They derived from published and unpublished itineraries, information on the age of the stand, the type of handwriting which identified the collector, etc. Coordinates are added only for localities outside the Netherlands; within the Netherlands, the province gives a clue in what general area of the country the bird was found (see Abbreviations).
Several other European bird collections have published an overview on the extinct and/or threatened birds in their collection. These are, listed by locality and in sequence of year of publication: Paris (Berlioz 1935, Jouanin 1962), Vienna (Sassi 1939), Berlin (Stresemann 1954), Frankfurt am Main (Mertens & Steinbacher 1955, Steinbacher 1959), Wroclaw and Warszawa (Peters 1960), La Rochelle (Jouanin 1966), Exeter (Howes 1969), Dresden (Eck 1970), Cambridge (Benson 1972), Moscow (Neufeldt 1978, Tomkovich & Barisheva 1987), Liverpool (Fisher 1981), Miland, Genoa, & Florence (Violani et al. 1984), St Petersburg (Sokolov & Il'yashenko 1987), Tring (Knox & Walters 1994), Lviv (Tsaryk 2000), Newcastle (Jessop & Stobbart 2002), and Sofia (Boev 2003).