Migratory dark-eyed juncos, Junco hyemalis, have better spatial memory and denser hippocampal neurons than nonmigratory conspecifics

Abstract The evolution of migration in an animal population produces a suite of physiological, behavioural and cognitive adaptations. Migratory birds, in particular, require the ability to return annually to breeding and wintering sites after long journeys, and thus might be predicted to have evolved enhanced spatial memory. In a comparison of two sparrow subspecies that co-occur in winter, the migratory subspecies (dark-eyed junco, Junco hyemalis hyemalis) performed better than the nonmigratory subspecies (J. h. carolinensis) on a room-scale spatial memory test. The migratory juncos also had more densely packed hippocampal neurons than did nonmigrants. Among nonmigrants, we looked for hippocampal differences between birds that occupied two home ranges annually and those that remained on their breeding territory year-round, to determine whether migration, per se, is related to neuroanatomical differences. However, we were unable to reach any conclusions because of low statistical power. A denser hippocampus could be the basis for better spatial memory in migrant juncos. Further testing of spatial memory on a landscape scale is needed to strengthen this argument and to understand cognitive differences between migrants and nonmigrants. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.

[1]  S. Healy,et al.  Development of hippocampal specialisation in two species of tit (Parus spp.) , 1994, Behavioural Brain Research.

[2]  M. Colombo,et al.  Is the avian hippocampus a functional homologue of the mammalian hippocampus? , 2000, Neuroscience & Biobehavioral Reviews.

[3]  Performance of Four Seed-Caching Corvid Species in the Radial-Arm Maze Analog , 1994 .

[4]  S. Healy,et al.  A larger hippocampus is associated with longer-lasting spatial memory , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[5]  P Ioalé,et al.  The homing pigeon hippocampus and the development of landmark navigation. , 1998, Developmental psychobiology.

[6]  Verner P. Bingman,et al.  Homing behavior of hippocampus and parahippocampus lesioned pigeons following short-distance releases , 1990, Behavioural Brain Research.

[7]  Sara J. Shettleworth,et al.  Matching location and color of a compound stimulus: Comparison of a food-storing and a nonstoring bird species. , 1995 .

[8]  S. Healy,et al.  Hippocampal volume in migratory and non-migratory warblers: effects of age and experience , 1996, Behavioural Brain Research.

[9]  A C Kamil,et al.  Differences in hippocampal volume among food storing corvids. , 1996, Brain, behavior and evolution.

[10]  T. Smulders,et al.  Seasonal variation in hippocampal volume in a food-storing bird, the black-capped chickadee. , 1995, Journal of neurobiology.

[11]  D. Sherry,et al.  Females have a larger hippocampus than males in the brood-parasitic brown-headed cowbird. , 1993, Proceedings of the National Academy of Sciences of the United States of America.

[12]  D. Brodbeck Memory for spatial and local cues: A comparison of a storing and a nonstoring species , 1994 .

[13]  T. Smulders,et al.  Effects of captivity and testosterone on the volumes of four brain regions in the dark-eyed junco (Junco hyemalis). , 2000, Journal of neurobiology.

[14]  Jacob Cohen Statistical Power Analysis for the Behavioral Sciences , 1969, The SAGE Encyclopedia of Research Design.

[15]  J. Krebs,et al.  Memory for spatial and object-specific cues in food-storing and non-storing birds , 1994, Journal of Comparative Physiology A.

[16]  P. Lavenex,et al.  Sex differences, but no seasonal variations in the hippocampus of food‐caching squirrels: A stereological study , 2000, The Journal of comparative neurology.

[17]  E. Ketterson,et al.  Geographic Variation and Its Climatic Correlates in the Sex Ratio of Eastern‐Wintering Dark‐Eyed Juncos (Junco Hyemalis Hyemalis) , 1976 .

[18]  Food storing does not affect hippocampal volume in experienced adult willow tits , 1996, Behavioural Brain Research.

[19]  Hippocampal volume and migration in passerine birds , 1991, The Science of Nature.

[20]  S. Shettleworth,et al.  Hippocampal lesions impair memory for location but not color in passerine birds. , 1996, Behavioral neuroscience.

[21]  S. Healy,et al.  Hippocampal specialization of food-storing birds. , 1989, Proceedings of the National Academy of Sciences of the United States of America.

[22]  F. Nottebohm,et al.  The telencephalon, diencephalon, and mesencephalon of the canary, Serinus canaria, in stereotaxic coordinates , 1974, The Journal of comparative neurology.

[23]  S. Healy,et al.  New tests for departures from random behavior in spatial memory experiments , 1996 .

[24]  J. Krebs,et al.  Hippocampal growth and attrition in birds affected by experience. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[25]  F. Nottebohm,et al.  Seasonal recruitment of hippocampal neurons in adult free-ranging black-capped chickadees. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[26]  D. Sherry,et al.  The hippocampal complex of food-storing birds. , 1989, Brain, behavior and evolution.

[27]  Russell P. Balda,et al.  Predicting Cognitive Capacity from Natural History , 1996 .

[28]  J. Blondel,et al.  Breeding time, food supply and fitness components of Blue Tits Parus caeruleus in Mediterranean habitats , 1996 .

[29]  C. Harley,et al.  Hippocampal Volume Is Related to Complexity of Nesting Habitat in Leach’s Storm-Petrel, a Nocturnal Procellariiform Seabird , 1999, Brain, Behavior and Evolution.

[30]  S. Siegel,et al.  Nonparametric Statistics for the Behavioral Sciences , 2022, The SAGE Encyclopedia of Research Design.

[31]  S. Volman,et al.  Relative hippocampal volume in relation to food-storing behavior in four species of woodpeckers. , 1997, Brain, Behavior and Evolution.

[32]  S. Shettleworth,et al.  Hippocampal volume and food-storing behavior are related in parids. , 1995, Brain, behavior and evolution.

[33]  P. Berthold,et al.  Genetic basis of migratory behavior in European warblers. , 1981, Science.

[34]  K. N. Rabenold,et al.  Variation in altitudinal migration, winter segregation, and site tenacity in two subspecies of Dark-eyed Juncos in the Southern Appalachians , 1985 .