. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. "DISTANCE EFFECT" IN ORIENTATION 517 scatter in their bearings (mean LMV =) but the mean vector is always oriented considerably west of the true home direction (mean HDC = ). Some re-analysis of Schmidt-Koenig's data in terms of homeward directedness of the mean vector and scatter of the bearings is possible. Thus, for example, if we look at the original data of Schmidt-Koenig (1966, page 41) from which Wall- raff (1967, page 340) graphed the homeward component of Schmidt-Koenig's releases from the west, we
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. "DISTANCE EFFECT" IN ORIENTATION 517 scatter in their bearings (mean LMV =) but the mean vector is always oriented considerably west of the true home direction (mean HDC = ). Some re-analysis of Schmidt-Koenig's data in terms of homeward directedness of the mean vector and scatter of the bearings is possible. Thus, for example, if we look at the original data of Schmidt-Koenig (1966, page 41) from which Wall- raff (1967, page 340) graphed the homeward component of Schmidt-Koenig's releases from the west, we discover that the nearly identical values for the home- ward component shown for the releases at 30 km and 40 km in Wallraff's curve result from very different behavior on the part of the pigeons. The homeward component of for 30 km is the average of the values (+ and —) for two releases both of which had bearings that were distributed nonrandomly (P < ) but in which the mean vectors were oriented in nearly opposite directions, one homeward and one away from home. By contrast, the homeward component 000. cP FIGURE 5. Release (A) showing very great scatter of the vanishing bearings, contrasted with a release (B) with little scatter but a mean deviating by a large angle from the home direction; A, Jersey Hill Fire Tower, New York, miles from the loft, August 2, 1968, home bearing 85°, mean bearing 269° (random, P — ) ; B, Castor Hill Fire Tower, New York, miles, July 31, 1969, home bearing 200°, mean bearing 272° (nonrandom, P = ). of for 40 km is the average of the values (+ and —) for two releases both of which yielded random bearings. Thus emphasis on the homeward com- ponent has resulted in lumping together as similar examples of poor homeward orientation at intermediate distances values resulting from fundamentally different behavior. (Values for distances and for homeward components mentioned here are estimate
Size: 2310px × 1082px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
