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Lysann Wagener, Andreas Nieder
Songbirds possess acute vision. How higher brain centers represent basic and parameterized visual stimuli to process sensory signals according to their behavioral importance has not been studied in a systematic way. We therefore examined how carrion crows (Corvus corone) and their nidopallial visual neurons process global visual motion information in dynamic random-dot displays during a delayed match-to-sample (DMS) task. The behavioral data show that moderately fast motion speeds (16 degrees of visual angle/second) result in superior direction discrimination performance...
October 8, 2016: European Journal of Neuroscience
Jonathan D Kennedy, Michael K Borregaard, Knud A Jønsson, Ben Holt, Jon Fjeldså, Carsten Rahbek
Regional variation in clade richness can be vast, reflecting differences in the dynamics of historical dispersal and diversification among lineages. Although it has been proposed that dispersal into new biogeographic regions may facilitate diversification, to date there has been limited assessment of the importance of this process in the generation, and maintenance, of broad-scale biodiversity gradients. To address this issue, we analytically derive biogeographic regions for a global radiation of passerine birds (the Corvides, c...
October 6, 2016: Evolution; International Journal of Organic Evolution
Brooke Maslo, Thomas A Schlacher, Michael A Weston, Chantal M Huijbers, Chris Anderson, Ben L Gilby, Andrew D Olds, Rod M Connolly, David S Schoeman
Coastal birds are critical ecosystem constituents on sandy shores, yet are threatened by depressed reproductive success resulting from direct and indirect anthropogenic and natural pressures. Few studies examine clutch fate across the wide range of environments experienced by birds; instead, most focus at the small site scale. We examine survival of model shorebird clutches as an index of true clutch survival at a regional scale (∼200 km), encompassing a variety of geomorphologies, predator communities, and human use regimes in southeast Queensland, Australia...
2016: PeerJ
Jayden O van Horik, Nathan J Emery
Physical cognition has generally been assessed in tool-using species that possess a relatively large brain size, such as corvids and apes. Parrots, like corvids and apes, also have large relative brain sizes, yet although parrots rarely use tools in the wild, growing evidence suggests comparable performances on physical cognition tasks. It is, however, unclear whether success on such tasks is facilitated by previous experience and training procedures. We therefore investigated physical comprehension of object relationships in two non-tool-using species of captive neotropical parrots on a new means-end paradigm, the Trap-Gaps task, using unfamiliar materials and modified training procedures that precluded procedural cues...
November 2016: Animal Cognition
Christian Rutz, Barbara C Klump, Lisa Komarczyk, Rosanna Leighton, Joshua Kramer, Saskia Wischnewski, Shoko Sugasawa, Michael B Morrissey, Richard James, James J H St Clair, Richard A Switzer, Bryce M Masuda
Only a handful of bird species are known to use foraging tools in the wild. Amongst them, the New Caledonian crow (Corvus moneduloides) stands out with its sophisticated tool-making skills. Despite considerable speculation, the evolutionary origins of this species' remarkable tool behaviour remain largely unknown, not least because no naturally tool-using congeners have yet been identified that would enable informative comparisons. Here we show that another tropical corvid, the 'Alalā (C. hawaiiensis; Hawaiian crow), is a highly dexterous tool user...
September 14, 2016: Nature
Jean-Nicolas Audet, Simon Ducatez, Louis Lefebvre
String-pulling is one of the most popular tests in animal cognition because of its apparent complexity, and of its potential to be applied to very different taxa. In birds, the basic procedure involves a food reward, suspended from a perch by a string, which can be reached by a series of coordinated pulling actions with the beak and holding actions of the pulled lengths of string with the foot. The taxonomic distribution of species that pass the test includes several corvids, parrots and parids, but in other families, data are much spottier and the number of individuals per species that succeed is often low...
2016: PloS One
John F Magnotti, Anthony A Wright, Kevin Leonard, Jeffrey S Katz, Debbie M Kelly
relational concepts depend upon relationships between stimuli (e.g., same vs. different) and transcend features of the training stimuli. Recent evidence shows that learning abstract concepts is shared across a variety species including birds. Our recent work with a highly-skilled food-storing bird, Clark's nutcracker, revealed superior same/different abstract-concept learning compared to rhesus monkeys, capuchin monkeys, and pigeons. Here we test a more social, but less reliant on food-storing, corvid species, the Black-billed magpie (Pica hudsonia)...
August 8, 2016: Psychonomic Bulletin & Review
S K Tahajjul Taufique, Vinod Kumar
Disruption of the cyclic feature of the day-night environment can cause negative effects on daily activity and advanced brain functions such as learning, memory and decision-making behaviour. These functions in songbirds, including corvids, involve the hippocampus, pallium and midbrain, as revealed by ZENK (a neuronal activation marker) and tyrosine hydroxylase (TH) expressions. TH is rate-limiting marker enzyme of the biosynthesis of dopamine, widely implicated in learning and memory. Here, we measured ZENK and TH immunoreactivity in the hippocampal, pallial and midbrain regions in response to cognitive performance (learning-memory retrieval) tests in Indian house crows (Corvus splendens) exposed to constant light environment (LL) with controls on 12h light:12h darkness...
November 1, 2016: Behavioural Brain Research
Ajaz Ahmad Bhat, Vishwanathan Mohan, Giulio Sandini, Pietro Morasso
Emerging studies indicate that several species such as corvids, apes and children solve 'The Crow and the Pitcher' task (from Aesop's Fables) in diverse conditions. Hidden beneath this fascinating paradigm is a fundamental question: by cumulatively interacting with different objects, how can an agent abstract the underlying cause-effect relations to predict and creatively exploit potential affordances of novel objects in the context of sought goals? Re-enacting this Aesop's Fable task on a humanoid within an open-ended 'learning-prediction-abstraction' loop, we address this problem and (i) present a brain-guided neural framework that emulates rapid one-shot encoding of ongoing experiences into a long-term memory and (ii) propose four task-agnostic learning rules (elimination, growth, uncertainty and status quo) that correlate predictions from remembered past experiences with the unfolding present situation to gradually abstract the underlying causal relations...
July 2016: Journal of the Royal Society, Interface
Alison L Greggor, Nicola S Clayton, Antony J C Fulford, Alex Thornton
The extent to which animals respond fearfully to novel stimuli may critically influence their ability to survive alongside humans. However, it is unclear whether the fear of novel objects, object neophobia, consistently varies in response to human disturbance. Where variation has been documented, it is unclear whether this variation is due to a change in fear towards specific novel stimuli, or whether it is symptomatic of a general change in fear behaviour. We measured levels of object neophobia in free-flying birds across urban and rural habitats, comparing corvids, a family known for being behaviourally flexible and innovative, with other urban-adapting bird species...
July 2016: Animal Behaviour
Trevor J Hamilton, Allison Myggland, Erika Duperreault, Zacnicte May, Joshua Gallup, Russell A Powell, Melike Schalomon, Shannon M Digweed
Episodic-like memory tests often aid in determining an animal's ability to recall the what, where, and which (context) of an event. To date, this type of memory has been demonstrated in humans, wild chacma baboons, corvids (Scrub jays), humming birds, mice, rats, Yucatan minipigs, and cuttlefish. The potential for this type of memory in zebrafish remains unexplored even though they are quickly becoming an essential model organism for the study of a variety of human cognitive and mental disorders. Here we explore the episodic-like capabilities of zebrafish (Danio rerio) in a previously established mammalian memory paradigm...
July 15, 2016: Animal Cognition
Leslie Foss, William K Reisen, Ying Fang, Vicki Kramer, Kerry Padgett
The California West Nile virus (WNV) Dead Bird Surveillance Program (DBSP) is an important component of WNV surveillance in the state. We evaluated FTA™ and RNASound™ cards as an alternative method for sampling dead birds for WNV molecular testing as these cards allow for more cost effective, rapid, and safer diagnostic sampling than the shipment of bird carcasses. To evaluate accuracy of results among avian sampling regimes, Reverse-Transcription Polymerase Chain Reaction (RT-PCR) results from FTA™ and RNASound™ cards were compared with results from kidney tissue, brain tissue, or oral swabs in lysis buffer in 2012-2013...
2016: PloS One
Seweryn Olkowicz, Martin Kocourek, Radek K Lučan, Michal Porteš, W Tecumseh Fitch, Suzana Herculano-Houzel, Pavel Němec
Some birds achieve primate-like levels of cognition, even though their brains tend to be much smaller in absolute size. This poses a fundamental problem in comparative and computational neuroscience, because small brains are expected to have a lower information-processing capacity. Using the isotropic fractionator to determine numbers of neurons in specific brain regions, here we show that the brains of parrots and songbirds contain on average twice as many neurons as primate brains of the same mass, indicating that avian brains have higher neuron packing densities than mammalian brains...
June 28, 2016: Proceedings of the National Academy of Sciences of the United States of America
Dave Freund, Sarah S Wheeler, Andrea K Townsend, Walter M Boyce, Holly B Ernest, Carla Cicero, Ravinder N M Sehgal
Leucocytozoon, a widespread hemosporidian blood parasite that infects a broad group of avian families, has been studied in corvids (family: Corvidae) for over a century. Current taxonomic classification indicates that Leucocytozoon sakharoffi infects crows and related Corvus spp., while Leucocytozoon berestneffi infects magpies (Pica spp.) and blue jays (Cyanocitta sp.). This intrafamily host specificity was based on the experimental transmissibility of the parasites, as well as slight differences in their morphology and life cycle development...
September 2016: Parasitology Research
Can Kabadayi, Lucy A Taylor, Auguste M P von Bayern, Mathias Osvath
Overriding motor impulses instigated by salient perceptual stimuli represent a fundamental inhibitory skill. Such motor self-regulation facilitates more rational behaviour, as it brings economy into the bodily interaction with the physical and social world. It also underlies certain complex cognitive processes including decision making. Recently, MacLean et al. (MacLean et al. 2014 Proc. Natl Acad. Sci. USA 111, 2140-2148. (doi:10.1073/pnas.1323533111)) conducted a large-scale study involving 36 species, comparing motor self-regulation across taxa...
April 2016: Royal Society Open Science
Edward W Legg, Ljerka Ostojić, Nicola S Clayton
A fundamental question about the complexity of corvid social cognition is whether behaviours exhibited when caching in front of potential pilferers represent specific attempts to prevent cache loss (cache protection hypothesis) or whether they are by-products of other behaviours (by-product hypothesis). Here, we demonstrate that Eurasian jays preferentially cache at a distance when observed by conspecifics. This preference for a 'far' location could be either a by-product of a general preference for caching at that specific location regardless of the risk of cache loss or a by-product of a general preference to be far away from conspecifics due to low intra-species tolerance...
July 2016: Animal Cognition
Onur Güntürkün, Thomas Bugnyar
Assumptions on the neural basis of cognition usually focus on cortical mechanisms. Birds have no cortex, but recent studies in parrots and corvids show that their cognitive skills are on par with primates. These cognitive findings are accompanied by neurobiological discoveries that reveal avian and mammalian forebrains are homologous, and show similarities in connectivity and function down to the cellular level. But because birds have a large pallium, but no cortex, a specific cortical architecture cannot be a requirement for advanced cognitive skills...
April 2016: Trends in Cognitive Sciences
Mario B Pesendorfer, T Scott Sillett, Scott A Morrison, Alan C Kamil
Corvids (crows, jays, magpies and nutcrackers) are important dispersers of large-seeded plants. Studies on captive or supplemented birds suggest that they flexibly adjust their scatter-hoarding behaviour to the context of social dynamics and relative seed availability. Because many corvid-dispersed trees show high annual variation in seed production, context-dependent foraging can have strong effects on natural corvid scatter-hoarding behaviour. We investigated how seed availability and social dynamics affected scatter-hoarding in the island scrub jays (Aphelocoma insularis)...
May 2016: Journal of Animal Ecology
Gabriele Droege, Till Töpfer
Corvids (Corvidae) play a major role in ornithological research. Because of their worldwide distribution, diversity and adaptiveness, they have been studied extensively. The aim of the Corvids Literature Database (CLD, is to record all publications (citation format) on all extant and extinct Crows, Ravens, Jays and Magpies worldwide and tag them with specific keywords making them available for researchers worldwide. The self-maintained project started in 2006 and today comprises 8000 articles, spanning almost 500 years...
2016: Database: the Journal of Biological Databases and Curation
Rachael Miller, Kate L Laskowski, Martina Schiestl, Thomas Bugnyar, Christine Schwab
Consistent individual differences in behaviour, or 'personality', are likely to be influenced by development, social context, and species ecology, though few comparative, longitudinal studies exist. Here, we investigated the role of development and social context on personality variation in two identically reared, social corvids: common ravens and carrion crows. We repeatedly presented subjects with a variety of novel food and objects, while alone and in a primarily sibling subgroup, from fledging to sub-adulthood...
2016: PloS One
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