Coastal Wairarapa/Wellington

I have separated out the sites in the coastal fringe of the Wairarapa- Wellington region as the moa fauna of this zone indicates a different environment to that immediately inland. There was a thin zone of dune grassland and coastal scrub that backed onto a broadleaf forest (karaka/kohekohe) along much of this coast. The fossil sites are all in the dunes or swamp deposits behind beach ridges. Fossil faunas are only just beginning to be developed from the sites in this zone, as in the past only moa bones were routinely collected. As a result, very small non-moa faunas are as yet available. 

  A diverse fauna from high dunes north of the Mataikona River, deposited under a coastal forest or scrub with no associated wetlands at about 100 m asl, includes Brown Teal. In contrast, at Te Kaukau Point a swamp deposit behind a raised beach ridge preserves a mixture of wetland and terrestrial species, including Brown Teal. Most recently, Brown Teal has been recorded from a coastal swamp deposit at Tora on the Wairarapa coast (A. Tennyson, pers. comm.). So it may be expected that Brown Teal used the coastal forest and swamps along the foot of the hill behind coastal terraces along the Wairarapa coastline.

Takaka Hill

All the Brown Teal listed for the Takaka region are from pitfall sites on Takaka Hill (Worthy & Holdaway 1994). None of these sites are near streams and the area was or is vegetated in a silver beech (Nothofagus menziesii) forest with some cedar (Libocedrus bidwilli) and rare podocarps such as totara (Podocarpus totara) contributing to the canopy. The most important site is Hobsons Tomo, which had a spectacular assemblage of small birds including many ducks. Radiocarbon dating of the main deposits (Worthy & Holdaway 1994) indicates deposition has occurred from the present day back in time to at least 14,000 ¹⁴C yrs BP. The old date was on a Finsch’s duck bone, and it is assumed that all four Finsch’s duck individuals, none of which where visible on the surface, were of pre-Holocene age. But there were also three blue duck and 38 Brown Teal present, most if not all of which will be of Holocene age. There is no wetland of any sort near the site and the nearest is over 1 kilometre distant. The evidence of this and several similar sites with fewer birds show that Brown Teal and blue ducks were using areas far from streams on Takaka Hill.

Mt Arthur and Mt Owen, northwest Nelson

These two localities have been separated out because they provide samples from the subalpine zone above the treeline, an area otherwise rarely represented in fossil deposits. No Brown Teal are known from sites close to or above the treeline in New Zealand, but that Finsch’s duck did use these habitats is shown by its presence in at least three sites. This is not just a function of taphonomy as other similar sized birds such as kakapo (Strigops habroptilus), weka (Gallirallus australis) and kiwi (Apteryx spp.) are common in subalpine sites.

West Coast karst

The data for the West Coast in Table 1 does not include any individuals from the Honeycomb Hill Cave System in the Oparara River headwaters. Some 20 km of surveyed passages in this system contain at least 70 discrete fossil sites known to be up to 20,000 years old (Worthy 1993). Brown teal are known from some of these sites, but summary data are not available. Similarly, Megamania Cave in the Gunner River has many discrete fossil sites and I observed Brown Teal in several of these in 1998, though most were not collected.  Both these cave systems lie in a mixed podocarp/ beech forest in a high rainfall area (c. 3000 mm per annum) at low altitude. The main canopy trees are rimu and red beech (Nothofagus fusca) with kamahi and rata on higher or steeper slopes, and there is a dense understorey with abundant lianas (kiekie Freycinetia banksii and supplejack Rhipogonum scandens), and moss covers most surfaces.

 The rest of the data from the West Coast are derived from studies in the Punakaiki karst, mainly between Charleston and Fox River (Worthy & Holdaway 1993). Anatids were rare in the combined fauna from this area, which may be partly due to the fact that rich pitfall faunas of birds smaller than moa were lacking. The Holocene vegetation is assumed to be much like that present in the area now and is very similar to that in the Gunner River and the Oparara, described above.

Coast of northern South Island

Around the coast of the northern South Island from Nelson to Marlborough there are a number of fossil sites in dunes. The most significant of these are Delaware Bay, Marfells Beach, and an eroding dune south of Mussel Point, just east of Marfells Beach. All have Brown Teal remains in them.  The Delaware Bay site is on a spit between the estuary and the ocean, so the presence of Brown Teal indicates probable use of the estuary.  The Marfells Beach site is similarly located on a spit seaward of an extensive shallow lagoon, while the site south of Mussel Point is on a coastal flat beside a rocky shore.  All three sites indicate the late Holocene use of coastal habitats by Brown Teal. The extensive data for the Marfells Beach site in particular (Worthy 1998c) shows that Brown Teal were the most numerous anatid in a very diverse fauna (Table 2). It was markedly more common than any of the more aquatic ducks, and only the paradise shelduck (Tadorna variegata) approached it in abundance, perhaps reflecting the presence of a large area of saltmarsh in which to graze.

Inland North Canterbury

Within the North Canterbury region I am including sites on Mt Cookson and others around Waikari described in Worthy & Holdaway (1995, 1996).  Holocene Hole is a pitfall trap on the Mt Cookson plateau and the surrounding area was vegetated in a mountain beech forest in the late Holocene, while this deposit accumulated.  No wetland is near this site, in which two Brown Teal were present. All the other records come from sites near Waikari. Three (Glencrieff, Pyramid Valley, and The Deans) are wetlands – a spring, a lake, and a swampy earth flow respectively.  The fourth site, Waikari Cave, is a pitfall (the only one in the area), but is within a few tens of metres of a stream.

 The anatid fauna of Pyramid Valley lake (Table 2) is significant as it shows that, in this shallow pond that was surrounded by tall matai forest during the period of deposition, Brown Teal were the most common duck. The absence of an aquatic macroflora is probably the reason why black swans (Cygnus atratus) were absent. One of the significant aspects of recent reassessment of the fauna at Pyramid Valley was that it revealed that grey teal were present prehistorically (Worthy & Holdaway 1996; Holdaway & Worthy 1997) apparently living with Brown Teal. While the regional fauna appears to be dominated by Finsch’s duck, this is mainly due to the large numbers from the pitfall site of Waikari Cave.  Finsch’s duck was derived from the wood duck (Chenonetta jubata) of Australia and is inferred to have been a grazing duck of terrestrial habitats (Worthy & Olson 2002). The drier regions in the east of the South Island afforded far greater areas of open vegetation, for example, scrub and grassland on the extensive river beds and on the higher slopes of hills, or on poorer soils, on which a grazing duck could feed. The Waikari Cave sample shows that in the Waikari area, Finsch’s duck dominated anatid faunas away from wetlands: it is much less common than Brown Teal in Pyramid Valley.

Table 2. A comparison of the anatid faunas from Pyramid Valley and Marfells Beach.

Inland South Canterbury

The faunas for inland South Canterbury are derived from the limestone areas of the inland downlands (Worthy 1997a). The sites include a mixture of swamp springs, pitfall traps in caves, and many predator sites accumulated by laughing owls or falcons.  The area is gentle rolling hill country 200 - 400 m asl, and during the late Holocene was probably vegetated in podocarp (matai-dominant) forest, with river flats containing areas of shrubland and grassland.

 Most Brown Teal records came from the rich pitfall trap of Kings Cave. This site is located on the side of a hill about 100 m distant from a small valley and stream. Three dates are available from the site which all show a late Holocene period of accumulation (Worthy 1997a). Of the 281 birds represented in the fauna, 100 are Finsch’s duck, 68 are kiwi, 20 weka (Gallirallus australis) and 38 are kakapo (Strigops habroptilus), demonstrating the overall terrestrial nature of this fauna. The only typically dabbling duck was grey duck represented by one modern bone, but there were at least 3 blue ducks and 7 Brown Teal, illustrating the propensity of these species to be found distant from waterways.

North Otago

The North Otago faunas are derived from the area south of the Waitaki River that lies towards the coast from Duntroon in the limestone downlands (Worthy 1998a). Here, Brown Teal occur in at least two of the several fossil bearing swamp deposits that have been discovered in the valleys between low limestone hills.  In some valleys there are limestone cliffs in which predator accumulations have been found and Brown Teal are in two of these sites. There is only a single pitfall site (Ngapara), which is located a few hundred metres from any stream and is not near any ponds.  The Ngapara site accounts for most of the Finsch’s duck individuals, indicating that in this region, as in inland Canterbury, Finsch’s duck dominates the anatid fauna of terrestrial ecosystems.

 The rolling hills of this area were probably vegetated much the same as the inland South Canterbury region discussed above. However, in the broad swampy valleys that typically lie between the hills, a swamp forest probably dominated by kahikatea (Dacrycarpus dacrydioides) was present, though other wetland podocarps such as yellow silver pine (Lepidothamnus intermedius) may have been present.

Central Otago

The single record of Brown Teal for central Otago comes from Earnscleugh Cave near Alexandra (Worthy 1998a). The fauna in this site is derived from both a pitfall and a predator accumulation. The site is several hundred metres up the side of a slope from the nearest stream. This site trapped most of the individual Finsch’s duck represented in the combined fossil fauna of the region, again reaffirming the dominance of this duck in dry eastern terrestrial ecosystems.

Southland

In Southland, most of the Brown Teal bones come from pitfall sites in low limestone ridges east of Winton (Worthy 1998b). While no Brown Teal bones are known from the several fossiliferous swamps in the region, this is probably more due to inept collection of material than their absence, as virtually no birds other than moa have been obtained from such sites. The ‘site’ termed Forest Hill Tomos is a general name for an unknown number of tomos or vertical pitfalls at Forest Hills, from which all the separate faunas were amalgamated as one, by the time of their study in the Otago Museum in 1997 (Worthy 1998b). Castle Rocks is the only one of the Brown Teal-bearing faunas to have been dated: a large series of radiocarbon dates indicates deposition during the late Holocene (Holdaway pers comm.). However, as most of the other collections are from surface deposits, a Holocene age is probably applicable to all. During this period the limestone ridge east of Winton (wherein lie the Forest Hills and McKerchars Cave sites) was clothed in tall rimu dominated podocarp forest.

 In the regional avifauna, Finsch’s duck dominate the anatid fauna as they do in other eastern areas with low rainfall, because of their abundance in some tomos.

Stewart Island

Natural fossil sites are rare on Stewart Island with the main locality being the dunes of Mason Bay. However, there seabirds dominate with few land or freshwater birds recovered to date (Worthy 1998f). The most important site otherwise is a dune site on Native Island which is accessible from the main Stewart Island by wading at low tide (Worthy 1998d). There is no freshwater on Native Island, so the ducks present must have either been using the vegetated island habitat or the shoreline, which is very sheltered being within Paterson Inlet. On Native Island, Brown Teal were associated with mergansers, grey ducks, paradise shelducks, and black swan, all known to use or have used marine habitats. Finsch’s duck is not recorded from Stewart Island.