Correct Feeder Research Articles

Effects of variable durations of food availability on interval time-place learning with pigeons Columba Livia

We assessed the effects of variable durations of food availability on an interval time-place learning task. 3 pigeons were exposed to a task in which food could be obtained for responses in one of four feeders according to an RI 25 s during 3 min, after which, food could be obtained on a different feeder according to the same schedule. The correct feeder changed following a fixed sequence that was repeated four times throughout the session. After 50 training sessions, an Open Hopper Test was conducted, after which, the second training condition ensued. This condition was like the first one with the exception that the availability period could be either 1,2,3, or 6 min long. A second test was conducted after 50 sessions of this training. Another group of 3 birds experienced these conditions in the reverse order. Data suggest that birds solved the task via interval timing under the fixed duration condition, and via ordinal timing when faced with variable durations. Birds learned the fixed sequence involved in the task under both conditions. Although the present data agree with previous research exploring variability in TPL tasks, they do not necessarily support previous claims for an asymmetrical role of spatial and temporal information in these tasks.

Social inhibition maintains adaptivity and consensus of honeybees foraging in dynamic environments.

To effectively forage in natural environments, organisms must adapt to changes in the quality and yield of food sources across multiple timescales. Individuals foraging in groups act based on both their private observations and the opinions of their neighbours. How do these information sources interact in changing environments? We address this problem in the context of honeybee colonies whose inhibitory social interactions promote adaptivity and consensus needed for effective foraging. Individual and social interactions within a mathematical model of collective decisions shape the nutrition yield of a group foraging from feeders with temporally switching quality. Social interactions improve foraging from a single feeder if temporal switching is fast or feeder quality is low. When the colony chooses from multiple feeders, the most beneficial form of social interaction is direct switching, whereby bees flip the opinion of nest-mates foraging at lower-yielding feeders. Model linearization shows that effective social interactions increase the fraction of the colony at the correct feeder (consensus) and the rate at which bees reach that feeder (adaptivity). Our mathematical framework allows us to compare a suite of social inhibition mechanisms, suggesting experimental protocols for revealing effective colony foraging strategies in dynamic environments.

Evidence of non-circadian timing in a low response-cost daily Time-Place Learning task with pigeons Columba Livia

Previous research has shown that rats require high response cost in order to display circadian timing in daily Time-Place Learning (TPL) tasks. For many possible reasons, no explicit effort to explore the effects of response cost on the performance of other species in these tasks has been made. Therefore, the present paper explores the effects of response cost on pigeon’s performance on a daily TPL task. Head entry responses were reinforced according to a Random Interval schedule of reinforcement on one feeder during morning sessions and on another feeder during afternoon sessions. Feeders were located 8 cm apart for one group of birds (Group Near) and 56 cm apart for another group (Group Far). After 50 training sessions, testing began. Test sessions consisted of skipping either the morning or the afternoon session. Results show that most birds in the near group respond primarily on the opposite feeder during the first 20 s of the test sessions and then they switch to the correct feeder. On the other hand, most birds in Group Far respond at the same rate on both opposite and correct feeders during 20 s, and then they respond primarily on the correct feeder. The possibility of these data revealing non circadian timing for birds in a low response-cost daily TPL task is discussed along with the implications of such a finding for previous literature that claims that this type of performance could be unique to rats.

Effects of variable sequences of food availability on interval time-place learning by pigeons

The effects of within session variability of the sequences of food availability in a 16 period Time Place Learning (TPL) task on the performance of pigeons were assessed. Two groups of birds were exposed to two conditions. For group 1 (N=3), the first condition consisted of a TPL task in which food could be obtained according to a Random Interval (RI) 25s schedule of reinforcement in one of four feeders, the correct feeder changed every 3min. The same sequence was repeated four times within every training session (Fixed Sequence). The second condition was exactly the same as the first one with the exception that the sequence in which the correct feeder changed was randomized, yielding a total of four randomized sequences of food availability each session (Variable Sequence). An Open Hopper Test (OHT) was conducted at the end of each condition. Birds in group 2 (N=3) experienced the same conditions but in the reverse order. Results showed high percent correct responses for both group of birds under both conditions. However, birds were able to time the availability period’s duration only under the Fixed Sequence condition, as shown by anticipation, anticipation of depletion and persistence of visiting patterns on the OHT. The implications of these results to Gallistels (1990) tripartite time-place-event memory code model are discussed, pointing out that these results are in line with previous findings about the important role that spatial parameters of a TPL task can play, for accurate timing was precluded when a variable sequence was employed.

The Effect of Social Hierarchy on Captive Coyote (Canis latrans) Foraging Behavior

AbstractForaging efficiency of individuals in pack forming species may be influenced by social dynamics within a pack. The effects of social hierarchy in particular may influence individual foraging behavior in canids, such as coyotes (Canis latrans). To examine the impact of social hierarchy on foraging behavior, we tested 16 captive coyotes in eight naturally established dominant–subordinate pairs, using the guesser–knower paradigm. We measured the efficiency of subordinate coyotes to relocate a food resource when alone and then allowed pairs to forage together, such that subordinates had prior knowledge of food location but dominants did not. To determine whether (1) subordinates used a direct or discursive strategy to obtain food in the presence of a dominant and (2) dominants used an exploitative or independent strategy to obtain food in the presence of a subordinate with previous knowledge, we measured their search efficiency (e.g., correct choice of area, feeder, and latency to correct feeder). Results showed subordinates learned to relocate food and increase efficiency when alone. In a social context, however, subordinate efficiency decreased. That is, subordinates approached the correct area, but searched more feeders before finding the correct one. Dominants initially used an independent search strategy but then quickly displaced the subordinate and monopolized the resource, reducing subordinate efficiency further. Despite continual displacement and reduction in efficiency, subordinates did not alter their foraging strategy over time. Our results suggest prior information can improve individual foraging advantage, but that social status strongly impacts individual foraging efficiency in social species such as coyotes.

Honeybee recruitment to scented food sources: correlations between in-hive social interactions and foraging decisions

Information exchange of environmental cues facilitates decision-making processes among members of insect societies. In honeybee foraging, it is unknown how the odor cues of a resource are relayed to inactive nest mates to enable resource exploitation at specific scented sources. It is presumed that bees need to follow the dance or to be involved in trophallaxis with a successful forager to obtain the discovered floral scent. With this in mind, we evaluated the influence of food scent relayed through in-hive interactions and the subsequent food choices. Results obtained from five colonies demonstrated that bees arriving at a feeding area preferred to land at a feeder carrying the odor currently exploited by the trained forager. The bees that landed at this feeder also showed more in-hive encounters with the trained forager than the individuals that landed at the alternative scented feeder. The most frequent interactions before landing at the correct feeder were body contacts with the active forager, a behavior that involves neither dance following nor trophallaxis. In addition, a reasonable proportion of successful newcomers showed no conspicuous interactions with the active forager. Results suggest that different sources of information can be integrated inside the hive to establish an odor-rewarded association useful to direct honeybees to a feeding site. For example, simple contacts with foragers or food exchanges with non-active foragers seem to be enough to choose a feeding site that carries the same scent collected by the focal forager.

Effects of hippocampal lesions on acquisition and retention of spatial learning in zebra finches

We tested the role of the hippocampus in spatial memory of zebra finches. The birds were trained to find the location of a food site among four identical feeders arranged on the aviary floor. Extra-maze cues were present. The birds had to perform the task from four different starting points. Successful visits and the time to find the food were recorded. Hippocampal lesions made before acquisition led to a decrease in correct choices. Hippocampal lesions following training disrupted the retention of the spatial memory. Surprisingly, birds with hippocampal damage reached the food as quickly as intact birds, but they needed more visits to find the correct feeder. Therefore, the birds with hippocampal damage used an alternative, nonspatial memory-based strategy to find the food.

Effects of supplementary hay in the diet of concentrate fed early weaned lambs

Early weaned lambs have been successfully reared to slaughter on ad libitum concentrate diets for many years, mainly in systems involving out of season lamb production where high market prices offset the comparatively high feed costs. In these systems maximum growth rates are required to enable lambs to reach acceptable slaughter weights before market prices fall.Feeding systems may be based on whole cereals supplemented with small, high protein pellets, a technique developed from Rowett studies (Orskov et al, 1974) or home made blends of processed cereals and by-products or proprietary concentrates. Component selection Is a common problem with diets based on whole grains and although this can largely be overcome by correct feeder design this incurs considerable expense. Diet selection can be reduced by processing grain (eg on farm rolling) or by pelleting. Cereal processing and pelleting however can have deleterious effects on rumen function as described by Orskov (1973), the effects being attributed to both inadequate saliva production and reduced rumen surface stimulation by roughage.

Attempts to condition homing pigeons to magnetic cues in an outdoor flight cage

An attempt was made to train 9 homing pigeons to respond to the presence or absence of bar magnets by turning either left or right after flying the length of a 20-ft outdoor flight cage. During initial training, color cues were placed in front of feeding stations on the left and right sides of the cage. The color cues were paired with magnetic cues by attaching either bar magnets or brass bars to the backs of the birds. The color cues were then deleted, leaving only the magnetic cues. Each pigeon received about 300 trials of color training followed by about 200 trials of magnet testing. When only magnetic cues remained, none of the pigeons were able to choose the correct feeder at greater than chance levels of probability.

The effect of cerebral ischaemia or intracarotid injection of methohexitone on short term memory in goats

Eight goats were surgically prepared with bilateral carotid loops and cranial implants connected to cortical and sub-cortical sites. The goats were trained in 3 delayed response tasks in which they had to choose the correct feeder from 3 situated in a large room. Training continued until the goats were performing successfully in the 3 tasks, usually with delays of up to 10 min. At this stage, the effect of a short period of disruption of brain electrical activity occuring during the delay period was investigated. Unconsciousness and frequently a temporary flattening of the cortical and subcortical EEG was produced either by means of cephalic ischaemia or by intra-carotid injection of methohexitone, a rapidly metabolised barbiturate. It was shown that a period of unconsciousness and temporary flattening of EEG occurring during the delay period did not impair the performance of the goats in the delayed response tasks. Assuming that isoelectric EEG implies absence of unit neuronal activity it is concluded that the type of recent memory involved in delayed response tasks does not require prolonged reverberatory neuronal activity but depends upon some intraneuronal chemical change.

Delayed response in blind cats before and after prefrontal ablation

Eleven cats were blinded by bilateral section of the optic nerve and trained on delayed response (DR) after 70 days' postoperative recovery. Six learned DR as well as normal cats; the remaining 5 animals either did not learn to approach the correct feeder, signalled by a continuous auditory cue, or failed to maintain correct approach behavior when a brief delay intervened between stimulus offset and response. Comparable failures were not observed in intact cats. The blind cats which met criterion on 30 sec delay were subjected to the bilateral ablation of the proreal and anterior orbital gyri. They showed the same deficits in postoperative retention of DR as sighted cats with these cortical lesions. This experiment demonstrates [1] that vision is necessary for immediate or delayed auditory localization by some cats, and [2] that prefrontal decortication has an equivalent effect on DR retention by cats that learned DR with or without vision.

The economics of direct current railway distribution: With particular reference to the automatic substation

The comparatively recent development of the full automatic substation and also the automatic substation combined with remote control, has served to re-open the entire subject of the economics of distribution. But quite aside from the questions that the automatic substation has presented, the great fluctuations in the prices of materials and of labor have made necessary renewed study of this subject. In other words, the proper design of a distribution system should represent a balance between all of the different items of cost that go to make up the total cost of power. Any change in the relative cost of materials as against labor or of a certain class of materials as against another class of materials tends to upset such a balance. Now that we begin to emerge from the unsettled conditions of the past few years during which the old relationships have been substantially changed, it is necessary to ask the question whether or not the rules by which distribution systems have been planned in the past still apply. More specifically, it is the purpose of this paper to determine, first, the relations that govern the size of feeders and the correct feeder layouts for any given arrangement of substations, and second, the principles underlying the correct location, size, and type of substations, assuming the fullest development of automatic and semi-automatic control. There is involved also the important question of stray currents. Regardless of the merits of the electrolysis controversy, the minimizing of stray currents is certainly to be desired by the electric railways. The most effective method of accomplishing this is increasing the number of distributing points. If a large number of distributing points be justified from an economic standpoint, and if furthermore this be found practicable from an operating standpoint, then the problem of electrolysis may perhaps cease to exist. Thus the inquiry is doubly pertinent. The cost of distribution in large cities of the size of Cleveland, Detroit, or St. Louis, comprising the carrying charges on the feeder, the heating losses in the feeders and the carrying charges on the equipment necessary to supply these losses, is considerably in excess of $200,000 per year. It is apparent that a careful study of this item of cost will more than likely be justified by the savings that will result. There are not at the present time sufficient accurate data on cost and performance of automatic substations to make possible a precise analysis of specific cases. In lieu of this it is the authors' purpose to show limiting conditions and by example to illustrate the relation of the various determining factors to the final cost.

The Economics of Direct-Current Railway Distribution With Particular Reference to the Automatic Substation

The comparatively recent development of the full automatic substation and also the automatic substation combined with remote control, has served to re-open the entire subject of the economics of distribution. But quite aside from the questions that the automatic substation has presented, the great fluctuations in the prices of materials and, of labor have made necessary renewed study of this subject. In other words, the proper design of a distribution system should represent a balance between all of the different items of cost that go to make up the total cost of power. Any change in the relative cost of materials as against labor or of a certain class of materials as against another class of materials tends to upset such a balance. Now that we begin to emerge from the unsettled conditions of the past few years during which the old relationships have been substantially changed, it is necessary to ask the question whether or not the rules by which distribution systems have been planned in the past still apply. More specifically, it is the purpose of this paper to determine, first, the relations that govern the size of feeders and the correct feeder layouts for any given arrangement of substations, and second, the principles underlying the correct location, size, and type of substations, assuming the fullest development of automatic and semi-automatic control. There is involved also the important question of stray currents.