Fig. 1. Jackass penguins sea along indicate islands penguins breed und - PDF document

Fig. 1. Jackass penguins sea along indicate islands penguins breed underwater sprint; (2) (3) 'normal' underwater travel; (4) travel; (5) home island (C) speed meter; Speed (km calculation, Source Jackass Penguin Jackass Penguin Jackass Penguin fledgling Jackass Penguin Jackass Penguin Jackass Penguin groups Jackass Penguin Jackass Penguin Jackass Penauin Penguin groups Jackass Penauin Little Blue Little Blue This study This study This study This study This study Sci. 1979 et al. Bemis 1979 Bemis 1979 Ecol. Prog. timed over m course pool. Vertical moult (Fig. are shown When travelling The under- Jackass Penguins in the bay was similar to radiographic speed distance These underwater speeds surface travelling speed. The spent on travelling Jackass Penguin was (Siegfried et Jackass Penguins swimming on the actual components, was 4.4 km actual travelling generally leave their islands around dawn and return in afternoon (Frost guin during the approximately period is fitted with distance meters km (SD 22.0) which means birds did venture further caught per distance travelled transects, no in Saldanha the bay. Penguins were found outside in water 30 to deep. Few the mean Penguins was the mean When disturbed a boat, the birds typically mean time 15 forag- the autoradiographic Maximum speeds Jackass Penguin 10 cm Webb 1975 Zweifel 1971 Etrumeus teres fishing vessel) Penguin dive This study Humboldt Penguin Spheniscus humboldti Gentoo Penguin et al. Gentoo Penguin Chinstrap Penguin Fishing 91 al. unpubl. Adelie Penguin anchovy ingested distance travelled Jackass Penguins breeding depth gauge in Fig. recorded was birds did at shallow depths. The mean spent deeper birds were assumed rather than full stomachs than anchovies and prey availability ability to enhances the Jackass Penguin in the Saldanha region is anchovy with full, partially full, empty stomachs t school, 50 t school schools 4 (13 stomachs 8 during such dives outside reflects a travelling Gentoo Chinstrap Penguins duration compared their foraging dives al. unpubl.). Penguins can al. 1971, Conroy Croxall 1983) in proximity with that no published data are available on species, e.g. occur within et al. Vilchez 1980) the Jackass Penguin necessitates a distributionally This condition is satisfied by a large, spatially many small prey is highly The Cape Anchovy occurs in small, Stuttaford 1983). fed on single, large, spatially predictable the same foraging trip irrespective how much spatially predictable was made birds would distances that no relation ingested. However, prey encounters, a positive correlation distance travelled seen in animals have decreases with increasing size causing dator-prey encounter rate makes feeding less planktivores (Eggers be feeding echo-sounder, set at hull mounted The trace was made are lantern Ecol. Prog. Ser. the even higher incidence Jackass Penguins implies that Jackass Penguins its limited National Geographic Memorial fund Research Institute their echotraces anchovy schools undertake research Thanks are to C. Nuclear Development Corporation D. Duffy manuscript. The was conducted while Gentoo Penguin Condor 85: Swimming speed E. M. light on vertical migrations the sea. Soc. Lond. Galapagos Penguin. Bird 15: schooling: a factor in reducing predation. Explor. Mer. Lond. 188: (1972). Diving Gentoo Penguin (Pygoscelis papua) Bull. 30: (1978). Moult resource division among Benguela upwelling Distribution, availability Bull. Un. ecology. Academic Press, London, (1980). Food, Linn. Soc. Lond. 14: H. (1977). on fish schools with Cons, int. (1968). Why Lond. 218: H. (1955). Rep. Div. C. (1983). The foraging on rate (1981). Oil Biochem. Physiol. 69: P. G. W. R., the Jackass Penguin between breed- Benguela region. Mar. Strand, S. R. W. (1983). Behavior Euphausia superba: their prey. systems in Sports fish- (Engraulis mordax). Bull. U.S. other fishes. Bull. U.S. 69: D., Parker, Frey, H. fishery: biological Technical Memorandum SWFC NO. (1980). Note the coastal waters Peru, with special reference tional Oceanographic Commission (IOC) Workshop Rep. Nino'. Guayaquil, Pesca 185: (1975). Behaviour In: Stonehouse, (1982). Diving Drabek, C. (1971). Diving S. (in Penguins at Island. South Orkney Islands. Zool., Lond. S., Croxall, Chinstrap Penguin The speed Ibis 97: South America. a pelagic predator school size density and volume. Mar Biol. 54: the Cape (Spheniscus demersus) South western Un. S. Experimental investigations respiratory function diving mammals (1982). A comparative study dicular musculature Smithson. contr. (1981). A note on Fish. Bull. Un. S. Afr. 14: (1975). Social schools in the upper mixed layer Sound Scattering Warrington, Virginia, Jackass penguins 75: 524 (1983). Anchovy Ship. News Euphausiid crustaceans in the West Afri- upwelling area. In: Boje, Lond. 255: (1975). Hydrodynamics W. R. eating penguins. Rec. 20: 159-162 A. (1907). Vertebrata. Section Aves. In: Antarctic Expedition Natural history, (1985). Seasonality in diet the Jackass Penguin, Diurnal foraging Jackass Penguin, penguins at sea. London, p. paper was presented by Professor