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Author Shettleworth, S.J.; Westwood, R.P. openurl 
  Title Divided attention, memory, and spatial discrimination in food-storing and nonstoring birds, black-capped chickadees (Poecile atricapilla) and dark-eyed juncos (Junco hyemalis) Type Journal Article
  Year 2002 Publication Journal of experimental psychology. Animal behavior processes Abbreviated Journal J Exp Psychol Anim Behav Process  
  Volume 28 Issue 3 Pages 227-241  
  Keywords Animals; Attention/*physiology; Behavior, Animal/physiology; Birds; *Discrimination (Psychology); *Food Habits; Memory/*physiology; Space Perception/*physiology; Spatial Behavior/*physiology  
  Abstract Food-storing birds, black-capped chickadees (Poecile atricapilla), and nonstoring birds, dark-eyed juncos (Junco hyemalis), matched color or location on a touch screen. Both species showed a divided attention effect for color but not for location (Experiment 1). Chickadees performed better on location than on color with retention intervals up to 40 s, but juncos did not (Experiment 2). Increasing sample-distractor distance improved performance similarly in both species. Multidimensional scaling revealed that both use a Euclidean metric of spatial similarity (Experiment 3). When choosing between the location and color of a remembered item, food storers choose location more than do nonstorers. These results explain this effect by differences in memory for location relative to color, not division of attention or spatial discrimination ability.  
  Address Department of Psychology, University of Toronto, 100 Saint George Street, Toronto, Ontario M5S 3G3, Canada. shettle@psych.utoronto.ca  
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  ISSN 0097-7403 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:12136700 Approved no  
  Call Number refbase @ user @ Serial 370  
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Author Gibson, B.M.; Shettleworth, S.J.; McDonald, R.J. openurl 
  Title Finding a goal on dry land and in the water: differential effects of disorientation on spatial learning Type Journal Article
  Year 2001 Publication Behavioural brain research Abbreviated Journal Behav. Brain. Res.  
  Volume 123 Issue 1 Pages 103-111  
  Keywords Animals; Cues; Environment; Male; Maze Learning/*physiology; Orientation/*physiology; Rats; Rats, Long-Evans; Spatial Behavior/*physiology; Water  
  Abstract Two previous studies, Martin et al. (J. Exp. Psychol. Anim. Behav. Process. 23 (1997) 183) and Dudchenko et al. (J. Exp. Psychol. Anim. Behav. Process. 23 (1997) 194), report that, compared to non-disoriented controls, rats disoriented before testing were disrupted in their ability to learn the location of a goal on a dry radial-arm maze task, but that both groups learned at the same rate in the Morris water maze. However, the radial-arm maze task was much more difficult than the water maze. In the current set of experiments, we examined the performance of control and disoriented rats on more comparable dry land and water maze tasks. Compared to non-disoriented rats, rats that were disoriented before testing were significantly impaired in locating a goal in a circular dry arena, but not a water tank. The results constrain theoretical explanations for the differential effects of disorientation on different spatial tasks.  
  Address Department of Psychology, University of Toronto, 100 St. George Street, Toronto, Ontario, Canada M5S 3G3. gibson@psych.utoronto.ca  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition (up)  
  ISSN 0166-4328 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:11377733 Approved no  
  Call Number refbase @ user @ Serial 372  
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Author Hampton, R.R.; Shettleworth, S.J. openurl 
  Title Hippocampus and memory in a food-storing and in a nonstoring bird species Type Journal Article
  Year 1996 Publication Behavioral neuroscience Abbreviated Journal Behav Neurosci  
  Volume 110 Issue 5 Pages 946-964  
  Keywords Animals; Appetitive Behavior/*physiology; Attention/physiology; Birds/*physiology; Brain Mapping; Feeding Behavior/*physiology; Mental Recall/*physiology; Organ Size/physiology; Orientation/*physiology; Retention (Psychology)/physiology; Species Specificity  
  Abstract Food-storing birds maintain in memory a large and constantly changing catalog of the locations of stored food. The hippocampus of food-storing black-capped chickadees (Parus atricapillus) is proportionally larger than that of nonstoring dark-eyed juncos (Junco hyemalis). Chickadees perform better than do juncos in an operant test of spatial non-matching-to-sample (SNMTS), and chickadees are more resistant to interference in this paradigm. Hippocampal lesions attenuate performance in SNMTS and increase interference. In tests of continuous spatial alternation (CSA), juncos perform better than chickadees. CSA performance also declines following hippocampal lesions. By itself, sensitivity of a given task to hippocampal damage does not predict the direction of memory differences between storing and nonstoring species.  
  Address Department of Psychology, University of Toronto, Ontario, Canada. robert@ln.nimh.nih.gov  
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  Series Volume Series Issue Edition (up)  
  ISSN 0735-7044 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:8918998 Approved no  
  Call Number refbase @ user @ Serial 375  
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Author Hampton, R.R.; Shettleworth, S.J. openurl 
  Title Hippocampal lesions impair memory for location but not color in passerine birds Type Journal Article
  Year 1996 Publication Behavioral neuroscience Abbreviated Journal Behav Neurosci  
  Volume 110 Issue 4 Pages 831-835  
  Keywords Animals; Appetitive Behavior/physiology; Birds/*physiology; Brain Mapping; Color Perception/*physiology; Discrimination Learning/physiology; Hippocampus/*physiology; Long-Term Potentiation/physiology; Mental Recall/*physiology; Orientation/*physiology; Species Specificity  
  Abstract The effects of hippocampal complex lesions on memory for location and color were assessed in black-capped chickadees (Parus atricapillus) and dark-eyed juncos (Junco hyemalis) in operant tests of matching to sample. Before surgery, most birds were more accurate on tests of memory for location than on tests of memory for color. Damage to the hippocampal complex caused a decline in memory for location, whereas memory for color was not affected in the same birds. This dissociation indicates that the avian hippocampus plays an important role in spatial cognition and suggests that this brain structure may play no role in working memory generally.  
  Address Department of Psychology, University of Toronto, Ontario, Canada  
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  ISSN 0735-7044 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:8864273 Approved no  
  Call Number refbase @ user @ Serial 376  
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Author Krebs, J.R.; Clayton, N.S.; Hampton, R.R.; Shettleworth, S.J. openurl 
  Title Effects of photoperiod on food-storing and the hippocampus in birds Type Journal Article
  Year 1995 Publication Neuroreport Abbreviated Journal Neuroreport  
  Volume 6 Issue 12 Pages 1701-1704  
  Keywords Animals; Birds; Eating/*physiology; Female; Hippocampus/*physiology; Light; Male; *Photoperiod; Seasons; Telencephalon/physiology; Time Factors  
  Abstract Birds that store food have a relatively large hippocampus compared to non-storing species. The hippocampus shows seasonal differences in neurogenesis and volume in black-capped chikadees (Parus atricapillus) taken from the wild at different times of year. We compared hippocampal volumes in black-capped chickadees captured at the same time but differing in food-storing behaviour because of manipulations of photoperiod in the laboratory. Differences in food-storing behaviour were not accompanied by differences in the volume of the hippocampus. Hippocampal volumes also did not differ between two groups of a non-food-storing control species, house sparrows (Passer domesticus), exposed to the same conditions as the chickadees.  
  Address Edward Grey Institute of Field Ornithology, Department of Zoology, Oxford, UK  
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  ISSN 0959-4965 ISBN Medium  
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  Notes PMID:8527745 Approved no  
  Call Number refbase @ user @ Serial 378  
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Author Hampton, R.R.; Sherry, D.F.; Shettleworth, S.J.; Khurgel, M.; Ivy, G. openurl 
  Title Hippocampal volume and food-storing behavior are related in parids Type Journal Article
  Year 1995 Publication Brain, behavior and evolution Abbreviated Journal Brain Behav Evol  
  Volume 45 Issue 1 Pages 54-61  
  Keywords Animals; Appetitive Behavior/*physiology; Birds/*anatomy & histology; Brain Mapping; Evolution; Food Preferences/physiology; Hippocampus/*anatomy & histology; Mental Recall/*physiology; Orientation/*physiology; Predatory Behavior/physiology; Social Environment; Species Specificity  
  Abstract The size of the hippocampus has been previously shown to reflect species differences and sex differences in reliance on spatial memory to locate ecologically important resources, such as food and mates. Black-capped chickadees (Parus atricapillus) cached more food than did either Mexican chickadees (P. sclateri) or bridled titmice (P. wollweberi) in two tests of food storing, one conducted in an aviary and another in smaller home cages. Black-capped chickadees were also found to have a larger hippocampus, relative to the size of the telencephalon, than the other two species. Differences in the frequency of food storing behavior among the three species have probably produced differences in the use of hippocampus-dependent memory and spatial information processing to recover stored food, resulting in graded selection for size of the hippocampus.  
  Address Department of Psychology, University of Toronto, Ontario, Canada  
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  ISSN 0006-8977 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:7866771 Approved no  
  Call Number refbase @ user @ Serial 379  
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Author Shettleworth, S.J.; Juergensen, M.R. openurl 
  Title Reinforcement and the organization of behavior in golden hamsters: brain stimulation reinforcement for seven action patterns Type Journal Article
  Year 1980 Publication Journal of experimental psychology. Animal behavior processes Abbreviated Journal J Exp Psychol Anim Behav Process  
  Volume 6 Issue 4 Pages 352-375  
  Keywords Animals; Behavior, Animal/*physiology; Cricetinae; Electric Stimulation; Female; Hypothalamus/*physiology; Male; Medial Forebrain Bundle/physiology; Mesocricetus; *Reinforcement (Psychology)  
  Abstract Golden hamsters were reinforced with intracranial electrical stimulation of the lateral hypothalamus (ICS) for spending time engaging in one of seven topographically defined action patterns (APs). The stimulation used as reinforcer elicited hoarding and/or feeding and supported high rates of bar pressing. In Experiment 1, hamsters were reinforced successively for digging, open rearing, and face washing. Digging increased most in time spent, and face washing increased least. Experiments 2-5 examined these effects further and also showed that “scrabbling,” like digging, was performed a large proportion of the time, almost without interruption, for contingent ICS but that scratching the body with a hindleg and scent-marking showed relatively little effect of contingent ICS, the latter even in an environment that facilitated marking. In Experiment 6, naive hamsters received ICS not contingent on behavior every 30 sec (fixed-time 30-sec schedule). Terminal behaviors that developed on this schedule were APs that were easy to reinforce in the other experiments, but a facultative behavior, face washing, was one not so readily reinforced. Experiment 7 confirmed a novel prediction from Experiment 6--that wall rearing, a terminal AP, would be performed at a high level for contingent ICS. All together, the results point to both motivational factors and associative factors being involved in the considerable differences in performance among different reinforced activities.  
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  ISSN 0097-7403 ISBN Medium  
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  Notes PMID:6968817 Approved no  
  Call Number refbase @ user @ Serial 386  
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Author Mrosovsky, N.; Shettleworth, S.J. openurl 
  Title Further studies of the sea-finding mechanism in green turtle hatchlings Type Journal Article
  Year 1974 Publication Behaviour Abbreviated Journal Behaviour  
  Volume 51 Issue 3-4 Pages 195-208  
  Keywords Animals; *Animals, Newborn/physiology; Contact Lenses; Locomotion; *Orientation; Retina/physiology; *Turtles/physiology; Visual Fields; *Visual Perception; Water  
  Abstract  
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  ISSN 0005-7959 ISBN Medium  
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  Notes PMID:4447586 Approved no  
  Call Number refbase @ user @ Serial 389  
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Author Cameron, E.Z.; du Toit, J.T. doi  openurl
  Title Winning by a neck: tall giraffes avoid competing with shorter browsers Type Journal Article
  Year 2007 Publication The American naturalist Abbreviated Journal Am Nat  
  Volume 169 Issue 1 Pages 130-135  
  Keywords Acacia/growth & development; Animals; Feeding Behavior/*physiology; Neck/*anatomy & histology; Plant Leaves/growth & development; Ruminants/*anatomy & histology/*physiology; South Africa  
  Abstract With their vertically elongated body form, giraffes generally feed above the level of other browsers within the savanna browsing guild, despite having access to foliage at lower levels. They ingest more leaf mass per bite when foraging high in the tree, perhaps because smaller, more selective browsers deplete shoots at lower levels or because trees differentially allocate resources to promote shoot growth in the upper canopy. We erected exclosures around individual Acacia nigrescens trees in the greater Kruger ecosystem, South Africa. After a complete growing season, we found no differences in leaf biomass per shoot across height zones in excluded trees but significant differences in control trees. We conclude that giraffes preferentially browse at high levels in the canopy to avoid competition with smaller browsers. Our findings are analogous with those from studies of grazing guilds and demonstrate that resource partitioning can be driven by competition when smaller foragers displace larger foragers from shared resources. This provides the first experimental support for the classic evolutionary hypothesis that vertical elongation of the giraffe body is an outcome of competition within the browsing ungulate guild.  
  Address Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa. ezcameron@zoology.up.ac.za  
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  ISSN 1537-5323 ISBN Medium  
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  Notes PMID:17206591 Approved no  
  Call Number refbase @ user @ Serial 410  
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Author Cameron, E.Z. doi  openurl
  Title Facultative adjustment of mammalian sex ratios in support of the Trivers-Willard hypothesis: evidence for a mechanism Type Journal Article
  Year 2004 Publication Proceedings. Biological sciences / The Royal Society Abbreviated Journal Proc Biol Sci  
  Volume 271 Issue 1549 Pages 1723-1728  
  Keywords Age Factors; Animals; Body Constitution; *Evolution; Female; Glucose/metabolism/physiology; Litter Size; Male; Mammals/*physiology; *Models, Biological; Reproduction/physiology; Seasons; Sex Factors; *Sex Ratio; Time Factors  
  Abstract Evolutionary theory predicts that mothers of different condition should adjust the birth sex ratio of their offspring in relation to future reproductive benefits. Published studies addressing variation in mammalian sex ratios have produced surprisingly contradictory results. Explaining the source of such variation has been a challenge for sex-ratio theory, not least because no mechanism for sex-ratio adjustment is known. I conducted a meta-analysis of previous mammalian sex-ratio studies to determine if there are any overall patterns in sex-ratio variation. The contradictory nature of previous results was confirmed. However, studies that investigated indices of condition around conception show almost unanimous support for the prediction that mothers in good condition bias their litters towards sons. Recent research on the role of glucose in reproductive functioning have shown that excess glucose favours the development of male blastocysts, providing a potential mechanism for sex-ratio variation in relation to maternal condition around conception. Furthermore, many of the conflicting results from studies on sex-ratio adjustment would be explained if glucose levels in utero during early cell division contributed to the determination of offspring sex ratios.  
  Address Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa. ezcameron@zoology.up.ac.za  
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  ISSN 0962-8452 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:15306293 Approved no  
  Call Number refbase @ user @ Serial 413  
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