Geolocation (Global Location Sensing or GLS logging) using archival light-recording tags offers considerable potential for tracking animal movements, yet few studies of flying seabirds have exploited this technology. Our study evaluated its effectiveness for determining foraging ranges of black-browed albatrosses Thalassarche melanophrys fitted simultaneously with GLS loggers and satellite-transmitters (Platform Terminal Transmitters, PTTs). After some preliminary validation, the position of an albatross could be determined by geolocation with a mean error ± SD of 186 ± 114 km (SDs of 1.66°and 1.82°of latitude and longitude, respectively). Errors from identical static loggers were lower (mean ± SD of 85 ± 47 km, with overall SDs of 0.61°and 0.99°of latitude and longitude, respectively) and less variable, with the difference attributable to variation in sensor orientation, intermittent shading by plumage, and the difficulty of correcting for extensive, potentially non-linear movements of flying birds. Iterative smoothing reduced both the mean error and the inflation of kernel ranges derived from GLS data, but over-smoothing contracted the extremes of the range. This reduced the overlap with radial cores apparent in the control data, and should be avoided for multinuclear GLS fix distributions. The accuracy of GLS tags is more than adequate for tracking migration and breeding-season foraging ranges of pelagic species, and for identifying broad-scale habitat preferences, overlap and potential conflict with commercial fisheries.

The precise relationship between the stem cells for the lymphoid system and those for the blood-forming system is unclear. While it is generally assumed that the hemopoietic stem cell, the spleen colony-forming unit (CFU-S), is also the stem cell for the lymphoid system, there is little evidence for this hypothesis. To investigate the stem cells in these two systems, we irradiated bone marrow cells to induce unique chromosome aberrations in the stem cell population and injected them at limiting dilution into stem cell-deficient recipients. Several months (between 3 and 11) were allowed for the injected cells to repopulate the hemopoietic system. At that time, the bone marrow, spleen, and thymus were examined for a high frequency of cells having the same unique chromosome aberration. The presence of such markers shows that the marker was induced in a cell with extensive proliferative capacity, i.e., a stem cell. In addition, the splenic lymphocytes were stimulated with phytohemagglutinin (PHA) or lipopolysaccharide (LPS) to search for unique chromosomes in dividing T and B cells, respectively. Finally, bone marrow cells were injected into secondary irradiated recipients to determine if the marker occurred in CFU-S and to determine whether or not the same tissue distributions of marked cells could be propogated by bone marrow cells in a second recipient. After examination of 28 primary recipients, it was possible to identify three unique patterns of stem cell regeneration. In one set of mice, a unique chromosome marker was observed in CFU-S and in PHA- and LPS-stimulated cultures. These mice provide direct evidence for a pluripotent stem cell in bone marrow. In addition, two restricted stem cells were identified by this analysis. In three recipients, abnormal karyotypes were found only in myeloid cells and not in B and T lymphocytes. These mice presumably received a marked stem cell restricted to differentiate only into myeloid progeny. In three other recipients, chromosome aberrations were found only in PHA-stimulated cells; CFU-S and cells from LPS cultures did not have cells with the unique chromosome. This pattern suggests that bone marrow contains cells committed to differentiation only into T lymphocytes. For each of the three types of stem cells, secondary recipients had the same cellular distribution of marked cells as the primary recipients. This observation provides further evidence that unique markers can be induced in both pluripotent and restricted stem cells.

We used satellite telemetry to examine the foraging ranges, feeding locations and travel speeds of 17 chick-rearing gannets Morus bassanus from the Bass Rock, SE Scotland. Regurgitates indicated that birds at the colony exploited a wide range of prey, frequently including 0-group sandeels (

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Consistent with an ordered immunoglobulin (Ig) gene assembly process during precursor (pre‐) B cell differentiation, we find that most Abelson murine leukemia virus (A‐MuLV)‐transformed pre‐B cells derived from scid (severe combined immune deficient) mice actively form aberrant rearrangements of their Ig heavy chain locus but do not rearrange endogenous kappa light chain variable region gene segments. However, we have identified several scid A‐MuLV transformants that transcribe the germline Ig kappa light chain constant region and actively rearrange the kappa variable region gene locus. In one case progression to the stage of kappa light chain gene rearrangement did not require expression of Ig mu heavy chains; furthermore, this progression could not be efficiently induced following expression of mu heavy chains from an introduced vector. As observed in pre‐B cell lines from normal mice, attempted V kappa‐to‐J kappa rearrangements in scid transformants occur by inversion at least as frequently as by deletion. The inverted rearrangements result in retention of both products of the recombination event in the chromosome, thus allowing their examination. scid kappa coding sequence joins are aberrant and analogous in structure to previously described scid heavy chain coding joins. In contrast, the recognition signals that flank involved coding segments frequently are joined precisely back‐to‐back in normal fashion. The scid VDJ recombinase defect therefore does not significantly impair recognition of, site‐specific cutting at, or juxtaposition and appropriate ligation of signal sequences. Our finding that the scid defect prevents formation of correct coding but not signal joins distinguishes these events mechanistically.