Longer Movements Research Articles

Adaptive search in juvenile plaice foraging for aggregated and dispersed prey

Juvenile plaice Pleuronectes platessa in a laboratory arena used intensive search behaviour, characterized by short movements and frequent turning, in the five movements before and after attacking a prey in an aggregated distribution. They used extensive search behaviour with, on average, longer movements and less turning at all other times. Intensive search was, apparently, triggered by a high local density of prey but not by isolated prey. This response to local prey density resulted in area‐restricted search when prey were aggregated and win‐shift behaviour when prey were dispersed. There was no evidence that the use of intensive search increased with experience of aggregated prey. It therefore appears that the fish were able to exploit encountered prey distribution patterns using their immediate perceptions rather than prior experience.

Adaptive search in juvenile plaice foraging for aggregated and dispersed prey

Juvenile plaice Pleuronectes platessa in a laboratory arena used intensive search behaviour, characterized by short movements and frequent turning, in the five movements before and after attacking a prey in an aggregated distribution. They used extensive search behaviour with, on average, longer movements and less turning at all other times. Intensive search was, apparently, triggered by a high local density of prey but not by isolated prey. This response to local prey density resulted in area-restricted search when prey were aggregated and win-shift behaviour when prey were dispersed. There was no evidence that the use of intensive search increased with experience of aggregated prey. It therefore appears that the fish were able to exploit encountered prey distribution patterns using their immediate perceptions rather than prior experience.

The relationship between uterine contractions, fetal movements and fetal heart rate patterns in the active phase of labor

The relationship between fetal movements, fetal heart rate and uterine contractions was studied with a computerized system in 18 parturients during the active phase of labor. 80% of FHR accelerations and 39% of uterine contractions were associated with fetal trunk movements. The probability of association was greater in longer movements and larger accelerations. 98% of fetal movements which lasted 10–15 s, 98% of accelerations with an amplitude of 25–30 bpm and 96.4% of accelerations with a duration of 40–50 s were associated with fetal trunk movements.

Growth and Survival of Willow Grouse Chicks in Relation to Home Range Size, Brood Movements and Habitat Selection

Spacing, movements and mortality of Willow Grouse Lagopus 1. lagopus broods were studied using radio-telemetry during three breeding seasons on a small island in northern Norway. Chicks survived worse during two cold summers with few insects than in a warm summer with many. In cold weather, many died at 3-5 days. Broods selected forests, bogs and fens, and shore vegetation which supported the largest number of insects. Mean differences between years in spacing and brood movements were small. Within years, growth was slower and survival lower among those broods with the greatest mobility and largest home ranges. Broods occupying small home ranges restricted their movements to areas especially rich in insects, whereas longer movements were made in poorer habitats. There appeared to be a dominance hierarchy among broods which effectively prevented them from occupying the same areas.

The Effect of Overt Rehearsal on Motor Short-Term Memory

The effects of different types of rehearsal on the recall of a blind motor movement were explored. Immediate recall and delayed recall (covert rehearsal) were compared to recall after the overt rehearsal of either movement distance or end-location. Spontaneous decay was evident in a large increase in variable error (VE) for all rehearsal conditions even though the location cue was reliable. Massed distance rehearsals yielded less VE than spaced, and VE increased with successive rehearsals, providing further support for spontaneous decay. Constant error showed a central tendency effect and decreased in overshooting over time. Longer movements yielded more VE than shorter, and the increase in VE over time was greater for longer movements, suggesting that retention characteristics may differ as a function of movement length.

Kinesthetic Recall And Information Bold>Reduction Activity

2 experiments are reported in which interpolated motor activity requiring either information reduction (1.86 bits) or no reduction was compared to a control to examine their effects on kinesthetic retention. Exp. 1 used an independent groups design and found only absolute error to increase over the delay intervals. Information reduction activity did not affect kinesthetic retention and there was increasing negative error for longer movements, with positive response sets for short movements and negative response sets for long movements. Exp. 2 replicated the retention interval conditions using a within-Ss design. No difference between conditions was found for either absolute or algebraic error, but an effect of Retention Intervals was found for absolute error. For both studies, the Interpolated Activity X Retention Interval interaction failed significance. No evidence was found to support interference or available processing capacity expalanation for the loss of retention.

Movements of Microtus pennsylvanicus in Relation to Depopulated Areas

Movements of individual voles were studied before, during, and after decimation of a segment of five Microtus pennsylvanicus populations. On each occasion a field was live-trapped and voles were marked; a central area of each field was then snap-trapped for 28 days. Snap-trap data demonstrated that 50% of all voles were live-trapped. Less than 11% of the marked voles moved into the central area after day three of the snap-trap period. Longer movements into this area were found with passage of time. A greater percentage of voles moved in from areas of high population densities, but distance of movement did not depend on density. Nonpregnant females moved farther than did pregnant females, but no significant difference was found between the number of each sex that moved into the area. From 80 to 100% of the residents were snap-trapped in the first three days. Two weeks were necessary to trap a number of incoming voles equal to the number of residents killed on that area. Time durations of stationary home ranges are presented. Comparisons are made between movements of Microtus and Peromyscus , and the effectiveness of trapping procedures is discussed.