Supporting Information Wilmshurst et al. 10.1073/pnas.0801507105 SI Text separate areas described by Worthy (2) and named 1: Test pit; 1. Stratigraphic Provenance of Seeds from South Island Sites. We 2: South Excavation; 3: Baulk (material between the Test Pit and (J.M.W. and T.F.G.H.) sampled over 1,600 seeds from peat or South Excavation and added to the Test Pit sample); 4: Enlarged sandy deposits preserved in five former swamp forests which Test Pit (lower faunal layer of units 1 and 3); 5: North Excavation have been drained, cleared, and converted to pasture over the (which contained a single infilled tuatara (Sphenodon sp.) or last 100 years. One of these sites, Nguroa Bay (172°38ЈE; 40°32’S) petrel burrow, not considered to have experienced recent or contained rat-gnawed as well as intact and bird-cracked seeds. continuous bioturbation (3); and 6: Against Cliff (mostly de- Waitoetoe-B (1), Wharariki (172°40ЈE; 40°30’S), Cannibal Bay scribed as ‘‘disturbed sediments’’, the lower faunal layer of this (169°44ЈE; 46°27’S), and Long Beach (170°38ЈE; 45° 45’S) con- unit was added to the Enlarged Test Pit sample). The relative tained only intact and bird-cracked seeds. All sites were about positions of these units are shown in Fig. S1. 1–2 km from the coast and at all sites except Nguroa Bay and The first sequence of bone AMS radiocarbon determinations Taranaki seeds were preserved in stratigraphic order and by age. published from these excavations (4) included three Pacific rat All species of seeds dated from the peat deposits are eaten by rats (Rattus exulans) bones and two bird bones, the latter were today including Prumnopitys taxifolia, P. ferruginea, Elaeocarpus reported as being from the same depths and were used as ‘‘paired hookerianus, and E. dentata. We selected a subsample of seeds samples’’ to provide independent support for the age of the rats. from each site for AMS radiocarbon dating by the Oxford However, the ages and depths of these determinations were Radiocarbon Accelerator Unit and Waikato Radiocarbon Dat- published with very little information regarding their exact ing Laboratory (the latter undertake chemical pretreatments, position (4). In response to criticism about the veracity of the old CO2 production and graphitization, and the graphite is analyzed rat bone ages, an attempt was made to validate the results by at Rafter). All seed dates and details of stratigraphy are pre- presenting three more rat bone dates after the 1995–1996 period sented in Table S2. (which were all less than 700 years BP), and two OSL dates from At Nguroa Bay, a reworked sandy deposit 2.25 m long, 35 cm the enclosing sediments (3). Although additional information wide, and Ϸ50 cm deep on the bank of a natural creek running was given about the stratigraphy, the exact locations of the bones along the length of a drained valley swamp was excavated in were still not made clear in all cases. Anderson & Higham (5) 10-cm spits and sieved for seeds (Ϸ300 collected). The highly critically reviewed the bone dating and stratigraphy in detail, and localized sand lenses were embedded in peat and overlay organic highlighted the problems with assumptions and stratigraphy. peats which contained wood. Seeds were most abundant in the 2.2 Reexcavation of Earthquakes #1 in 2006. Our (J.M.W., A.J.A., sand lenses, particularly in the upper 10 cm. The sand deposit T.F.G.H., and T.H.W.) reexcavation of Earthquakes #1 had thinned away from the side of the creek to less than 5 mm on the three components (Fig. S1): surface of the drained swamp. Sand lenses had poorly defined 1. A working pit. This consisted of the ‘‘North’’ excavation and boundaries suggesting the sand had been reworked by high- part of the ‘‘Test pit’’ excavation (2), plus Ϸ0.2mby0.3mtothe rainfall events, and during these periods the seeds have been west of the North excavation. All this appeared to be fill from the entrained and buried in the sand. Rat-gnawed seeds made up 1995 excavation and it was spaded out. 13% of the total seeds collected. Three seeds were also dated 2. The result was a 1-m-long by 0.7-m-deep northern wall of from test pits 600 m upstream at 10–20 cm depth (Nguroa Bay material undisturbed by excavation which was component 2. Road). North of this our main excavation, called ‘‘North Extension’’, At Wharariki, 113 seeds were collected, from a peat deposit extended 0.5 m north to south. buried under 50 cm of clay topsoil. The site was a valley peat 3. Immediately east of the working pit was an area of the which had deposited behind dunes and was at least 4m deep. ‘Against Cliff’ excavation, but east of it again was a strip of Seeds were sieved from 10-cm spits of peat, but were only found previously unexcavated material under a low limestone overhang at 50 cm and below. We selected seeds for dating from 50–60 cm, which we excavated as ‘East sampling area’. The East sampling where they were also most abundant. area and the North Extension were excavated by observed layers At Cannibal Bay, Ϸ300 seeds were collected from a 60-cm- and 10-cm spits. All material was sieved to 1 mm and everything deep organic peat deposit overlaying sterile sand. The peat retained for sorting and identification of faunal bones. deposits had accumulated in a depression between raised dunes. In summary, we excavated a sample of Earthquakes #1, which The seeds were sieved from the peat in 20-cm spits, from the contains stratigraphic units that are the continuation of Layers surface down to 60 cm. We dated a subsample of seeds from 0–20 1 and 3 as designated in the original excavations, and which might cm and 50–60 cm. Two seeds were also dated from a forest soil include Layer 2 as an unfossiliferous band that is unrecognizable under a P. ferruginea canopy in Cannibal Bay (20–30 cm depth). by color variation. Our excavation showed that bioturbation is At Long Beach, Ϸ500 seeds were sampled from a peat deposit extensive across the deposit (Figs. S2 and S3) and reaches from at least 90 cm deep which had formed in a depression behind the surface to at least 85 cm in depth, which is well below the sand dunes. Seeds were sieved from the peat in 10-cm spits from fossiliferous units of interest. As North Extension is located the surface down to 90 cm, but were only found at 20 cm and adjacent to the earlier North excavation, the extensive rabbit below. Seeds were most abundant at 30–40 cm. We dated a burrowing recognized across North Extension must have ex- subsample of seeds from 20–30 cm. tended at least some way into the North excavation seriously compromising the original stratigraphy from the top to the 2. Stratigraphic Provenance of Bones from Earthquakes #1. 2.1 Sum- bottom. Below is a detailed description of our excavation of the mary of previous excavation and radiocarbon dating. The faunal re- North Extension sampling area. mains found in a laughing owl (Sceloglaux albifacies) midden at Our observed stratigraphy of the North Extension is broadly the base of a small overhanging cliff at Earthquakes #1 rock similar to that recorded in the earlier excavations at Earthquakes shelter in North Otago were originally excavated in 1995 and #1 (Fig. S1). The general pattern in the original work consisted described in detail (2). The excavation was complex with six of 13–18 cm of Layer 1 (friable, fossiliferous, reddish silts), 8–12 Wilmshurst et al. www.pnas.org/cgi/content/short/0801507105 1of13 cm of pale unfossiliferous silts (Layer 2) overlying the reddish by rabbits (Figs. S2 and S3). These burrows contained mixed fossiliferous silts of Layer 3. Our excavation has the same total assemblages of bones including those from recently introduced depth of fossiliferous silts (excluding in areas of bioturbation) fauna (rats, rabbits, mice, skylark, blackbird), and species now and our Layer 3 is very comparable in material and extent to the extinct from the mainland (e.g., tuatara – one of which was dated original Layer 3. Our Layer 1, although we saw it as yellow-gray to 1029 Ϯ 25 yrs BP: OxA-15197), suggesting both recent and to yellow-brown rather than reddish, is otherwise comparable in significant bioturbation, which is contrary to the original inter- material and extent to the original Layer 1, but it is deeper pretation (3). because we saw no stratigraphic evidence of the earlier Layer 2. We dated bones of taxa considered to be rat-vulnerable (i.e., The color differences may reflect different weathering regimes extinct well before European arrival, or extant only on rat-free as our North Extension excavation was more sheltered under the islands in New Zealand) from the surface, and at 0–10 cm and rock overhang than most of the previous excavated area, which 10–26 cm below the surface, including from within the burrow in consequence was likely wetter more often. The three main fills (Table S1). Rat bones were also dated from the same levels. units we recognized in the North Extension stratigraphy (Fig. S1) Our dates from the rat-vulnerable fauna did not overlap with are described in detail below. dates on rat bones excavated from the same layers (apart from Layer 1: At the top, beneath about 5 cm of very loose silt and long- lived Tuatara – Table S1), and there was no chronological recent sheep droppings (which were swept off the surface and order with depth for any of the bones dated (Table S1).