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Tool Modification and Use by an American Crow
Abstract
An American Crow (Corvus brachyrhynchos) was observed to modify and use a piece of wood as a probe.
... Crows and other members of family Corvidae (corvids) are widely regarded as among the most intelligent bird species (Emery & Clayton 2004, Lambert et al. 2019); many are capable of long-term human facial recognition (Marzluff et al. 2010), understanding and responding to reward inequity (Wascher & Bugnyar 2013), assessing risk (Dufour et al. 2019), tracking and remembering the actions of others (Borborwicz & Osvath 2019), manufacturing rudimentary tools (Hunt 1996, Caffrey 2000, Shumaker et al. 2011, Uomini & Hunt 2017, and potentially possessing a theory of mind , Ostojić 2013, Bugnyar et al. 2016, though see Van der Vaart 2012). Corvids are also capable of social learning; American crows (Corvus brachyrhynchos) learn new dangers and keep track of predators by observing conspecific behavior (Cornell et al. 2011, Swift & Marzluff 2015, while New Caledonian crows (Corvus moneduloides) and common ravens (Corvus corax) obtain information on how to acquire food socially (Heinrich et al. 1993, Sierro et al. 2019. ...
Crows and other birds in the family Corvidae regularly share information to learn the identity and whereabouts of dangerous predators, but can they use social learning to solve a novel task for a food reward? Here, we examined the factors affecting the ability of 27 wild‐caught American crows to solve a common string pulling task in a laboratory setting. We split crows into two groups; one group was given the task after repeatedly observing a conspecific model the solution and the other solved in the absence of conspecific models. We recorded the crows’ estimated age, sex, size, body condition, level of nervousness, and brain volume using DICOM images from a CT scan. Although none of these variables were statistically significant, crows without a conspecific model and large brain volumes consistently mastered the task in the minimum number of days, whereas those with conspecific models and smaller brain volumes required varying and sometimes a substantial number of days to master the task. We found indirect evidence that body condition might also be important for motivating crows to solve the task. Crows with conspecific models were no more likely to initially solve the task than those working the puzzle without social information, but those that mastered the task usually copied the method most frequently demonstrated by their knowledgeable neighbors. These findings suggest that brain volume and possibly body condition may be factors in learning new tasks and that crows can use social learning to refine their ability to obtain a novel food source, although they must initially learn to access it themselves.
... American crows are also active hunters that prey on small animals and the eggs and nestlings of other bird species. The American crow has been observed in other parts of the world carrying hard-shelled mollusks high into the air to drop them on rocks in order to break them open, and is one of only a few species of bird that has been observed modifying and using tools to obtain food (Caffrey, 2000). Crows also hide/bury food in various locations (a behaviour known as caching) so that they can return and consume it at a later date. ...
This plan outlines actions required for the management of pest crows on Bermuda.
... New Caledonian crows also frequently engage in bark flaking (43% of recorded bill interactions in a study using bird-borne miniature video cameras; [11]), and exhibit a wide range of tool-processing behaviours [2,3,8,[11][12][13][14][15][16][17][18], but to our knowledge, there have been no reports of bark tool use in the wild. Interestingly, the only observation to date of a wild American crow C. brachyrhynchos using a tool for (presumed) extractive foraging involved the use of a wooden splinter, which the bird had released from a fence post through pecking and pulling [19]. A useful non-corvid comparison is provided by nuthatches Sitta spp. that are known to use bark tools, illustrating how this tool type can aid foraging for arthropod prey (for a review and photos illustrating the behaviour, see [20]). ...
Very few animal species habitually make and use foraging tools. We recently discovered that the Hawaiian crow is a highly skilled, natural tool user. Most captive adults in our experiment spontaneously used sticks to access out-of-reach food from a range of extraction tasks, exhibiting a surprising degree of dexterity. Moreover, many birds modified tools before or during deployment, and some even manufactured tools from raw materials. In this invited addendum article, we describe and discuss these observations in more detail. Our preliminary data, and comparisons with the better-studied New Caledonian crow, suggest that the Hawaiian crow has extensive tool-modification and manufacture abilities. To chart the full extent of the species’ natural tool-making repertoire, we have started conducting dedicated experiments where subjects are given access to suitable raw materials for tool manufacture, but not ready-to-use tools.
... In the light of an increasing number of anecdotal observations, across species and ecological contexts, nuthatch tool behaviour clearly deserves systematic investigation. It is particularly important to establish how much these birds rely on tool-assisted foraging (see Morse, 1968)-that is, whether the behaviour is expressed sporadically by just a few birds (such as in the American crow: Caffrey, 2000) or routinely by entire populations (New Caledonian and Hawaiian crow: Hunt, 1996;Rutz & St Clair, 2012;Rutz et al., 2016). ...
Here, we report an observation of a Eurasian nuthatch Sitta europaea foraging with a tool in a public park in Greater London, UK. This record is of significance, as it provides the first photographic evidence (to our knowledge) of nuthatch tool use, reveals an unusually wide phylogenetic and geographic distribution of tool behaviour within the Sittidae, and constitutes a rare example of animal tool use in an urban environment. To improve our understanding of nuthatch tool behaviour, we are building a global database of relevant anecdotal field observations—submissions are most welcome.
... C. cornix) might have been related to the artificiality of the materials used in the tests (Miller et al. 2016). No individual crows in our population behaved the same all the time, yet some individuals were notably more bold and aggressive than others, some more inquisitive than others, some more playful, some seemed more prone to routine, some (mostly females) were especially gentle and caring with nestlings, and a few seemed particularly smart, e.g., the individual that made a tool with which to probe a space too small for its head (Caffrey 2000b), and AM (Appendix 4, and 3b, and Appendix A 1a in Caffrey and Peterson 2015). ...
During the nestling stage of breeding seasons in Stillwater, OK, pairs of American Crows (Corvus brachyrhynchos brachyrhynchos) lived alone or in groups of variable composition; auxiliaries included individuals that had delayed dispersal, immigrated into groups, or returned to natal territories after having lived elsewhere. Most, but not all, auxiliaries contributed to feeding nestlings, and their contributions varied considerably. On average, breeders fed nestlings at greater rates than did auxiliaries, and female breeders spent more time at nests than did other group members. Breeders compensated for auxiliary contributions by reducing their own; this and breeder responses to the disappearance of auxiliary feeding group members provide evidence that these long-lived, iteroparous animals were managing energy budgets so as to maximize fitness over the long term. Female breeders in larger groups spent more time at nests than did those in smaller groups, but not for expected reasons and not to any reproductive benefit. A few female auxiliaries spent increasing amounts of time at nests as nestlings aged. No other measured phenotypic characteristic of individuals was found to explain any of the wide variation in the patterns of nestling care exhibited by members of our population.
... Jones, 1979;Banks, 1982;Bowey, 1997 Ardea goliath Wood et al., 1875;Duerden, 1908;Lindblom, 1920;van Lawick-Goodall & van Lawick, 1966;Brown & Urban, 1969;Brooke, 1979;Ilany, 1982 Nestor notabilis Taylor, 1975;Janzen et al., 1976; Pterocles burchelli Spotted sandgrouse & Bowman, 1967;Greenhood & Norton, 1999;Tebbich et al., 2002Tebbich et al., , 2004 (Continued.) Genus species Ivor, 1941Ivor, , 1955 Catharus fuscescens Veery Grobecker & Pietsch, 1978;Montevecchi, 1978;Phillips, 1978;Cristol & Switzer, 1999;Caffrey, 2000Caffrey, , 2001Balda, 2007 Corvus caurinus Jewett, 1924;Zach, crow 1978Zach, crow , 1979Richardson & Verbeek, 1987 Corvus corax Corvus corone Goodwin, 1953a;Londei crow & Maffioli, 1978;Condor & Everett, 1979;Jones, 1979;Berrow et al., 1992;Rolando & Zunino, 1992;Mienis, 1993;Brampton, 1994;Nihei, 1995Nihei, , 1998 (Continued.) Genus species Edmonds, 1991;McMillan, 1992;Slee, 1992 Corvus monedula Jackdaw Ivor, 1941Ivor, , 1955Potter, 1970;Jones & Kamil, 1973 Cyanocitta stelleri Steller's jay Purser, 1959;Potter, 1970;Hammond, 1997 Passerella Chaffer, 1945;Gannon, violaceus 1930;Marshall, 1960 Pycnonotus cafer Ivor, 1941;Hill, 1946;Laskey, 1948;Rand, 1967;Nicklas, 1974;Wible, 1975;Jackson, 1985;Pitochelli, 1985;Clark et al., 1999 Regulus satrapa Ivor, 1955;Southern, 1963;Potter, 1970;Radford, 1979;Clark et al., 1990;Judson & Bennett, 1992 Tangara Fisher, 1939;Murie, 1940;Kenyon, 1958;Hall & Schaller, 1964;Ebert, 1968;Houk & Geibel, 1974;Wade, 1975 Galidia elegans Leland, 1977;Antinucci & Visalberghi, 1986;Visalberghi, 1990Visalberghi, , 1993Fernandes, 1991;Anderson & Henneman, 1994;Westergaard & Suomi, 1994Lavallee, 1999;Boinski et al., 2000;Cleveland et al., 2004 Struhsaker, 1975;Starin, 1990 Erythrocebus Patas Kortlandt & Kooij, 1963;Redshaw, 1975;Fontaine et al., 1995;Nakamichi, 1999;Breuer et al., 2005;Pouydebat et al., 2005;Wittiger & Sunderland-Groves, 2007 Hylobates Karrer, 1970;Artaud & Bertrand, 1984;Zuberbühler et al., 1996;Malaivijitnond et al., 2007;Watanabe et al., 2007;Masataka et al., 2009;Gumert et al., 2009 Macaca Jordan, 1982;Gold, 2002;Mulcahy & Call, 2006 ( van Lawick-Goodall et al., 1973;Pettet, 1975;Pickford, 1975;Benhar & Samuel, 1978;Oyen, 1979;Westergaard, 1992Westergaard, , 1993 Papio Bolwig, 1961;Marais, 1969; baboon Hamilton III et al., 1975 Pongo Orangutan N N Y Y F C, F C, F C, F F C, F F 17 Schaller, 1961;Ellis, 1975; pygmaeus Galdikas, 1982Galdikas, , 1989Miller & Quiatt, 1983;Call & Tomasello, 1994;Rogers & Kaplan, 1994;O'Malley & McGrew, 2000;Peters, 2001;van Schaik & Knott, 2001;Fox & bin'Muhammad, 2002;van Schaik et al., 2003a, b;Fox et al., 2004;Nakamichi, 2004;Mulcahy & Call, 2006 Presbytis ...
Despite numerous attempts to define animal tool use over the past four decades, the definition remains elusive and the behaviour classification somewhat subjective. Here, we provide a brief review of the definitions of animal tool use and show how those definitions have been modified over time. While some aspects have remained constant (i.e., the distinction between 'true' and 'borderline' tool use), others have been added (i.e., the distinction between 'dynamic' and 'static' behaviours). We present an updated, comprehensive catalog of documented animal tool use that indicates whether the behaviours observed included any 'true' tool use, whether the observations were limited to captive animals, whether tool manufacture has been observed, and whether the observed tool use was limited to only one individual and, thus, 'anecdotal' (i.e., N = 1). Such a catalog has not been attempted since Beck (1980). In addition to being a useful reference for behaviourists, this catalog demonstrates broad tool use and manufacture trends that may be of interest to phylogenists, evolutionary ecologists, and cognitive evolutionists. Tool use and tool manufacture are shown to be widespread across three phyla and seven classes of the animal kingdom. Moreover, there is complete overlap between the Aves and Mammalia orders in terms of the tool use categories (e.g., food extraction, food capture, agonism) arguing against any special abilities of mammals. The majority of tool users, almost 85% of the entries, use tools in only one of the tool use categories. Only members of the Passeriformes and Primates orders have been observed to use tools in four or more of the ten categories. Thus, observed tool use by some members of these two orders (e.g., Corvus, Papio) is qualitatively different from that of all other animal taxa. Finally, although there are similarities between Aves and Mammalia, and Primates and Passeriformes, primate tool use is qualitatively different. Approximately 35% of the entries for this order demonstrate a breadth of tool use (i.e., three or more categories by any one species) compared to other mammals (0%), Aves (2.4%), and the Passeriformes (3.1%). This greater breadth in tool use by some organisms may involve phylogenetic or cognitive differences — or may simply reflect differences in length and intensity of observations. The impact that tool usage may have had on groups' respective ecological niches and, through niche-construction, on their respective evolutionary trajectories remains a subject for future study.
Corvids (Family: CORVIDAE) are a clade of some 120 species widespread throughout much of the world that have attracted the interest of researchers due to their impressive cognitive abilities. The group is, however, also generally described as neophobic, a trait that increases the difficulty of undertaking such research. In Australia, Torresian crows (Corvus orru) have, like corvid species worldwide, thrived in urban environments, sharing this habitat with a number of other corvoid (Superfamily: CORVOIDEA) species. While each of these species has successfully colonised urban areas, the extent to which neophobia is present is not known. This study empirically tested the extent to which neophobia is exhibited in wild urban Torresian crows by measuring the delaying effect of a novel object to obtaining food and any changes in neophobic behaviours displayed. This was then compared with the other urban corvoid species that inhabit similar niches. This study confirmed that Torresian crows are significantly wary of a novel objects, displaying more neophobic behaviours and taking longer to attain the food. Crow behaviour provided evidence in support of both the dangerous niche hypothesis and the two-factor model of neophobia and neophilia. Crows also displayed these behaviours to a significantly greater extent than the three other corvoids studied. However, the individual variation in crow behaviours when exposed to a novel object was extensive. This variation may be attributed to differing behavioural types between individuals, or different experiences with novel objects or humans in the bird's past.
The capacity for specialization and radiation make fish an excellent group in which to investigate the depth and variety of animal cognition. Even though early observations of fish using tools predates the discovery of tool use in chimpanzees, fish cognition has historically been somewhat overlooked. However, a recent surge of interest is now providing a wealth of material on which to draw examples, and this has required a selective approach to choosing the research described below. Our goal is to illustrate the necessity for basing cognitive investigations on the ecological and evolutionary context of the species at hand. We also seek to illustrate the importance of ecology and the environment in honing a range of sensory systems that allow fish to glean information and support informed decision-making. The various environments and challenges with which fish interact require equally varied cognitive skills, and the solutions that fish have developed are truly impressive. Similarly, we illustrate how common ecological problems will frequently produce common cognitive solutions. Below, we focus on four topics: spatial learning and memory, avoiding predators and catching prey, communication, and innovation. These are used to illustrate how both simple and sophisticated cognitive processes underpin much of the adaptive behavioral flexibility exhibited throughout fish phylogeny. Never before has the field had such a wide array of interdisciplinary techniques available to access both cognitive and mechanistic processes underpinning fish behavior. This capacity comes at a critical time to predict and manage fish populations in an era of unprecedented global change.
The capacity for specialization and radiation make fish an excellent group in which to investigate the depth and variety of animal cognition. Even though early observations of fish using tools predates the discovery of tool use in chimpanzees, fish cognition has historically been somewhat overlooked. However, a recent surge of interest is now providing a wealth of material on which to draw examples, and this has required a selective approach to choosing the research described below. Our goal is to illustrate the necessity for basing cognitive investigations on the ecological and evolutionary context of the species at hand. We also seek to illustrate the importance of ecology and the environment in honing a range of sensory systems that allow fish to glean information and support informed decision-making. The various environments and challenges with which fish interact require equally varied cognitive skills, and the solutions that fish have developed are truly impressive. Similarly, we illustrate how common ecological problems will frequently produce common cognitive solutions. Below, we focus on four topics: spatial learning and memory, avoiding predators and catching prey, communication, and innovation. These are used to illustrate how both simple and sophisticated cognitive processes underpin much of the adaptive behavioral flexibility exhibited throughout fish phylogeny. Never before has the field had such a wide array of interdisciplinary techniques available to access both cognitive and mechanistic processes underpinning fish behavior. This capacity comes at a critical time to predict and manage fish populations in an era of unprecedented global change. WIREs Cogn Sci 2015, 6:159-176. doi: 10.1002/wcs.1337 For further resources related to this article, please visit the WIREs website.
The authors have declared no conflicts of interest for this article.
© 2015 John Wiley & Sons, Ltd.
Once considered only a human behavior, reports of tool use by a variety of animals have accumulated. Likewise, various definitions of tool use have also amassed. Although some researchers argue that understanding the evolutionary drivers of tool use is more important than identifying and describing these behaviors, the central issue of defining what constitutes tool use has not been fully addressed. Here we analyze prominent definitions of tool use and review the application of these definitions in scientific and educational literature. We demonstrate that many behaviors recently described as tool use do not meet criteria for prevalent definitions, while other neglected behaviors may constitute a form of tool use. These examples show how the use of inconsistent definitions of tool use in research can result in different conclusions from the same observations. Our aim is to demonstrate that a universally acceptable definition of tool use based on traditional, evolutionary, and operational understanding of behavior is needed. The rationale is that this review will stimulate the consistent and explicit use of specific terminology in tool use research. This would help define specific examples of each natural observation from a common measuring stick, allowing better comparative studies and classification of these unique behaviors.
Laboratory-raised Northeirn blue jays (Cyanocitta cristata) have been observed tearing pieces from pages of newspaper and utilizing them as tools to rake in food pellets which were otherwise
out of reach. The frequency of this behavior was dependenit upon the motivational state of the jay and the presence of food
pellets.
TOOL behaviour in wild birds has been described as mostly
stereotyped1,2, and tool manufacture involves little
modification of material3–5. Here I report in New
Caledonian crows Corvus moneduloides the manufacture and use of two
different types of hook tool to aid prey capture: hooked-twig and stepped-cut
barbed pandanus leaf. Crow tool manufacture had three features new to tool use
in free-living nonhumans: a high degree of standardization, distinctly discrete
tool types with definite imposition of form in tool shaping, and the use of
hooks. These features only first appeared in the stone6 and
bone7 tool-using cultures of early humans after the Lower
Palaeolithic6,7, which indicates that crows have achieved a
considerable technical capability in their tool manufacture and use.