Ulson, S. L., and H. F. James. 1996. Prehistoric status and -.- ..I distribution of the IIawaiian hawk (Buteo soliturius), with the first fossil record from Kaua'i. Bishop Museum BISHOF Records of the Hawaii Biological Survey for 1996-Part Notes 65 Occasional Papers 49:65-69. 2: ~le1. Average point count ,,..,...-- ,-. Prehistoric Status and Distribution of the Hawaiian Hawk ~aiiduring November 1996. Sampling at 610 m. above diversion. (Buteo solitarius),with the First Fossil Record from Kauai Species Density (m') STORRSL. OLSON' & HELENP. JAMES' (Department of Veflebrate Zoology. National Museum of clcs Cascade Pool Slde Pool Rlme Run Natural History, Smithsonian Institution, Wnshington DC 20560, USA) ripes concolor 0 0.3 0 0 0 Introduction ~elleri 0 0 0 0 0.3 Although listed as an endangered species, the Hawaiian Hawk or 'io (Birreo soli~ar- lnrki 0 0.3 0 0 0 ius Peale, 1848) is widely distributed on the island of Hawaii (Scott er al., 1986), where oida bisulcarn 29 * 29 223.5 * 34.8 118 *25.8 124.3 * 32.3 263.8 * 37.8 it now feeds mainly on introduced rodents and thus may even have benefited from anthro- palagrion spp. Absent Absent Absent Absent Absent pogenic changes in the fauna and flora. That this relatively large, seemingly vagile preda- tor has not been recorded with certainty in the historic period on any of the other Hawaiian islands has long been puzzling. The diverse deposits of fossil birds in the Hawaiian rcolor could navigate the ditch intake during baseflow, as streamflow is quite low. Islands (Olson & James, 1982, 1991; James & Olson, 1991) have hitherto yielded scant The second major factor is that there were several permanent pools and shallow runs information on the Hawaiian Hawk, the only record away from the island of I-Iawaii being ~taininghigh densities of Xiplrophorus lrelleri in the diverted stretch of Lalakea Stream. a single occurrence on Molokai (Olson & James. 1982). y postlarval Let~ripesconcolor stranded in these pools would face heavy predation by :cn swordtails. l'his is due to thcir diurnal behavior and propensity of postlarval Flrst Kauai Occurrence nripcs concolor to swim near the surface of the water (Tate. 1995). Introduced parasites Here we report the first fossil record of Hawaiian Hawk for Kauai, from the same lm green swordtails are another problem threatening Lcnlipes concolor in Lalakea area in the Makawehi dunes near Poipu where almost all other fossil birds have been .earn. Lcnripcs concolor have been exposed to parasites brought with recent introduced found so far on Kauai (Olson &James, 1982). Fossils from these dunes represent an inter- h species (Font & Tate. 1994). The increase in disease exposure of Lcnripes concolor esting but far from complete avifauna, most of which was recovered in 1976 and 1977, rm parasitism undoubtedly adversely impacts the survival rates for these fish (Font & with little new being added in subsequent years. te, 1994). On 1 March 1996, Olson, with D.A. and L.P. Burney, located a new fossil site in the Makawehi Dunes, here designated K-4 (coordinates taken by Global Positioning System terature Cited = 21 "52'48"N, 159°26'03"W). This site faces south on a cliff overlooking the ocean where ~ker,J.A. & S.A. Foster. 1992. Esritnaring density and abundance of endetnicjishes in it is exposed to onshore winds. Near the top of the cliff, these winds are eroding uncon- Hnwniirrtr srreottrs. Hawaii Division of Aquatic Resources. 50 p. solidated, clean, yellowish sand that is overlain by an extremely indurated layer of light cvick, \V.S., J.M.Fltulmons & R.T.Nlsl~lmoto. 1992. Cortservarion of Hawaiian grayish sandstone about 25 cm thick. The wind creates hollows undcr this indurated layer. fishwarerfishes. Hawaii Division of Aquatic Resources. 26 p. which is sometimes held up temporarily by pillars of more consolidated sand, until the ~nt.W.F. & D.C. Tate. 1994. Helminth parasites of native Hawaiian freshwater fishes: indurated layer becomes too cantilevered to support the overlying strata and breaks off in large blocks that litter the slopes of the cliff. an example of extreme ecological isolation. J. Parasirol. 80: 682-688. Bones at this site are weathering out of the hollows beneath the indurated layer and lacdonald, G.A., A.T. Abbott & F.L. Peterson. 1983. Volcanoes in rhe sea: geology occur both in place and scattered through the sand that has cascaded down the slope. They of Hawaii. University of Hawaii Press, Honolulu, Hawaii. 517 p. appear to be mineralized and are heavily encrusted with sand. Although the naturc of rte, D.C. 1995, ncllavioral nnd ~l~orphologicaldevelopment of immature Hawaiian dunes makes it notoriously difficult to derive meaningful stratigraphic inferences, wc freshwnter fislies. Ph.D. dissertation, Louisiana State University. 98 p. believe that it is likely that the bones from this site are older than Holocene. Because they occur at the windward edge of a sea-cliff, there now exists no source for the sand under which the bones were buried. Therefore, the deposition of the bones must have taken place during a lower sea-level stand when the dunes originally formed and before the dunes became perched above cliffs by the erosion of a rising sea. Almost all of the bones collected at site K-4 are of Wedge-tailed Shearwaters (PuDnus pacificus). a seabird that still attempts to breed in the area. The only exception was a complete left coracoid of a hawk. This was originally heavily encrusted with sand. which was removed with dilute acetic acid. The specimen (Fig. 1) was found to be of a size compatible with females of Buteo solirariru (Table I). with which it agrees in all other details of morphology, so we identify it with that species. I. Research As~ociatcin Zoology. Dcpanmcnc of Natural Sclenccs, --Bishop Museum. Honol~ 66 BISHOP MUSEUM OCCASIONAL PAPERS: No. 49, 1997 Records of the Hawaii Biological Survey for 1996Part 2: Notes 67 Table 1. Measurements (mm) of comparative skeletons of Bureo soli~ariirsand fossils. Coracoid Humerus Length Width of Length Distal width sternal facet Females 34.2-34.8 12.6-12.9 82.0-84.6 14.6-14.9 Males 30.3-32.3 10.9-1 2.6 7 1.6-77.9 12.9-13.8 Kauai fossil 34.3 12.6+ Molokai fossil 83.7 14.6 Scurcity or the Hawaiian I-iawk in ihe Fossil Record Remains of the tlawaiian Hawk are encountered occasionally in lava tubes on the lccward slopes of tl~eislalid of Iiawaii (S. Olson & H.F. James, unpubl. data). In alniost all illstances, however, these are in an archeological context, among the refuse of human occupalion, suggesting that Hawaiians caught these birds and presumably ate them or tlscd their feathers. We have encountered only a single individual, a skeleton in a lava tube o11 Mt. Hualalai, that evidently was not preserved as a result of human agency. On Maui, natural accumulations of bones of birds have been found in numerous lava tubes on the leeward slopes of MI. Haleakala. Although a considerable variety of species is represcntcd, not a single bone of a hawk has yet been found. This negative evidence is i~~conclusivefor Bureo, especially considering that the endemic harrier Circus dossetlus, which is known from Molokai and probably occurred on Maui as well, is likewise absent I'rol~itile fossil rccord there. In the extensive dune systems of Molokai, where large samples of fossil birds have been obtained at the Moomomi Dunes and at llio Point, we have encountered remains of tlr~rcoonly once. These were 3 bones (see "Malerial examined") which may well have come from a single individual, found in a large, steep, sheltered depression in the dunes known as Site 6 (Olson & James, 1982). Large concentrations of bones of Bonin Petrel (P~erotlrott~nI~ypole~tca), along with remains of fish and shells of edible mollusks such as opil~iand pipipi. indicate former human occupation of this site, so that most bird bones here may derive from midden deposits. It is possible, though unlikely, that a hawk could have been broughl to Molokai from Hawaii. More probably it was a local bird that became illcorporatcd into the dunes as a result of human activity. Because its possible human asso- ciations makc the record somewhat equivocal, the fossil from Kauai, which must antedate the arrival of humans in the islands, becomes the more significant. The island of Oahu has a particularly rich fossil record. Bones of birds occur pri- marily in Holoce~lcsediments trapped in limestone sinkholes at Barbers Point, and in a Pleistocene lake bcd at Ulupau Head that is more than 120,000 yr old (James, 1987). In tile Pleistocene site, bones of B~treoare unusually common, the birds apparently having been attracted to the lakeshore environment. However, thesc bones are not identifiable as Fig. 1. Lefl coracoids of Hawaiian Hawk (Burro soliiarius) in ventral view. The larger specimen on Uirteo soli~ariitsbut are from a larger species of as yet undetermined affinities. Either the the leh (USNM 490733) is a fossil from the Mnkawehi dunes on Kauni, presuniably from a female, hawk represented at Ulupau evolved irito the modem Hawaiian Hawk, or the species contrasted with that from a modem skeleton of a male, which is the smaller sex (BPBM 147954). The scale is in mm. bccame extinct in tlie islands. In either case, not a single bone of Bit~eohas yet been found I.* 1- 68 BISHOP MUSEUM OCCASIONAL PAPERS: No. 49, 1997 Records of the Hawaii Biological Survey for 1996Part 2: Notes 69 in the very extensive accumulations of Holocene bones from Barbers Point.