Age and hunting success in the brown pelican: influences of skill and patch choice on foraging efficiency

We hypothesize that megafauna extinctions throughout the Pleistocene, that led to a progressive decline in large prey availability, were a primary selecting agent in key evolutionary and cultural changes in human prehistory. The Pleistocene human past is characterized by a series of transformations that include the evolution of new physiological traits and the adoption, assimilation, and replacement of cultural and behavioral patterns. Some changes, such as brain expansion, use of fire, developments in stone-tool technologies, or the scale of resource intensification, were uncharacteristically progressive. We previously hypothesized that humans specialized in acquiring large prey because of their higher foraging efficiency, high biomass density, higher fat content, and the use of less complex tools for their acquisition. Here, we argue that the need to mitigate the additional energetic cost of acquiring progressively smaller prey may have been an ecological selecting agent in fundamental adaptive modes demonstrated in the Paleolithic archaeological record. We describe several potential associations between prey size decline and specific evolutionary and cultural changes that might have been driven by the need to adapt to increased energetic demands while hunting and processing smaller and smaller game.

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Flight speed, foraging efficiency, and daily energy budget of the Barn Swallow, Hirundo rustica

Canadian Journal of Zoology ◽

10.1139/z97-140 ◽

1997 ◽

Vol 75 (7) ◽

pp. 1176-1183 ◽

Cited By ~ 1

Author(s):

Horacio de la Cueva ◽

Robert W. Blake

Keyword(s):

Doppler Radar ◽

Flight Speed ◽

Hirundo Rustica ◽

Foraging Efficiency ◽

Barn Swallow ◽

Aerodynamic Model ◽

Daily Energy ◽

Energy Store ◽

The Mean ◽

Barn Swallows

Aerodynamic power equations predict optimal speeds at which birds ought to fly if they are to maximize time spent in the air on a given energy store (minimum power speed, Vmp), distance covered using a given amount of fuel (maximum range speed, Vmr), and rate of delivering food to the chicks in the nest (Vnest), or maximize the daily energy balance (VDBAL). With the aerodynamic model employed, these speeds are 5.3, 7.0, 7.9, and 8.9 m∙s−1, respectively, for the Barn Swallow, Hirundo rustica. A comparison of the predicted flight speed with both the mean and median flight speeds (8 m∙s−1 in both cases; n = 821) recorded with Doppler radar indicates that Barn Swallows fly at speeds not significantly different from Vnest. The true sample size was unknown, and realistic sample sizes are drawn with bootstrap procedures and compared with those given by the number of measurements (821); no significant differences were found. To test the model, energy requirements for growth, prey density, and time spent foraging were varied independently in a sensitivity analysis. Large but realistic changes in these three variables do not contradict the model and predict speeds within the range measured in the field.

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EXPRESS: Two Variations and One Similarity in Memory Functions Deployed by Mice and Humans to Support Foraging

Quarterly Journal of Experimental Psychology ◽

10.1177/17470218211010576 ◽

2021 ◽

pp. 174702182110105

Author(s):

Spencer Talbot ◽

Todor Gerdjikov ◽

Carlo De Lillo

Keyword(s):

Working Memory ◽

Brain Function ◽

Visual Cues ◽

Brain Structures ◽

Human Cognition ◽

Foraging Efficiency ◽

Long Term Memory ◽

Memory Functions ◽

Term Memory

Assessing variations in cognitive function between humans and animals is vital for understanding the idiosyncrasies of human cognition and for refining animal models of human brain function and disease. We determined memory functions deployed by mice and humans to support foraging with a search task acting as a test battery. Mice searched for food from the top of poles within an open-arena. Poles were divided into groups based on visual cues and baited according to different schedules. White and black poles were baited in alternate trials. Striped poles were never baited. The requirement of the task was to find all baits in each trial. Mice’s foraging efficiency, defined as the number of poles visited before all baits were retrieved, improved with practice. Mice learnt to avoid visiting un-baited poles across trials (Long-term memory) and revisits to poles within each trial (Working memory). Humans tested with a virtual-reality version of the task outperformed mice in foraging efficiency, working memory and exploitation of the temporal pattern of rewards across trials. Moreover, humans, but not mice, reduced the number of possible movement sequences used to search the set of poles. For these measures interspecies differences were maintained throughout three weeks of testing. By contrast, long-term-memory for never-rewarded poles was similar in mice and humans after the first week of testing. These results indicate that human cognitive functions relying upon archaic brain structures may be adequately modelled in mice. Conversely, modelling in mice fluid skills likely to have developed specifically in primates, requires caution.

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Lightning predator: the Ferruginous Pygmy Owl snatches flower-visiting hummingbirds in southwestern Brazil

Revista Brasileira de Ornitologia ◽

10.1007/bf03544283 ◽

2015 ◽

Vol 23 (1) ◽

pp. 12-14 ◽

Cited By ~ 2

Author(s):

Ivan Sazima

Keyword(s):

Stage I ◽

Large Concentration ◽

Hunting Success ◽

Flower Visiting ◽

Glaucidium Brasilianum

Abstract Pygmy owls of the genus Glaucidium prey on large insect and small vertebrates, mostly birds. Among the birds preyed on by pygmy owls are hummingbirds, caught mostly while mobbing these owlets or when still at nestling stage. I report here on the Ferruginous Pygmy Owl (Glaucidium brasilianum) snatching flower-visiting hummingbirds in an orchard at a farm in southwestern Brazil. I recorded one White-tailed Goldenthroat (Polytmus guainumbi) and three Gilded Hummingbirds (Hylocharis chrysura) preyed on by this owlet on three consecutive days. The large concentration of flowers and, consequently, of hummingbirds in the orchard likely contributed to the hunting success of the owlet on such fleeting and quickly moving prey. The role this pygmy owl plays on predation of adult hummingbirds in the Neotropics merits closer consideration.

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Population control by means of organised hunting effort: Experiences from a voluntary goose hunting arrangement

AMBIO ◽

10.1007/s13280-021-01590-2 ◽

2021 ◽

Author(s):

Ingunn M. Tombre ◽

Fredrik Fredriksen ◽

Odd Jerpstad ◽

Jan Eivind Østnes ◽

Einar Eythórsson

Keyword(s):

Population Control ◽

Stakeholder Participation ◽

Management Plan ◽

International Management ◽

Optimal Timing ◽

Management Actions ◽

Anser Brachyrhynchus ◽

Management Objectives ◽

Hunting Success ◽

Goose Hunting

AbstractImplementing management objectives may be challenging when decisions are made at different scales than where they are supposed to be carried out. In this study we present a situation where local goose hunting arrangements respond to objectives in an international management plan for pink-footed geese (Anser brachyrhynchus) and a local wish to reduce goose numbers as means to reduce grazing damage on farmland. A unique ten-year dataset provides an evaluation of the efficiency of voluntary actions at a local scale for implementing a policy of population control of geese, and general lessons are drawn for collaboration and co-production of knowledge for adaptive management. The study demonstrates how both the hunters and geese adapt in a situation where increasing the harvest of geese is the main objective. Introducing hunting-free days and safe foraging areas significantly increased goose numbers in the study area, with a corresponding increase in hunting success in terms of number of harvested geese. The geese’s behavioural response to hunting also triggered the hunters to adapt accordingly by optimal timing and placement in the landscape. Based on the results of the present study we suggest a framework for local implementation of management actions. Bringing end-users on board, facilitates processes and strengthens the achievements, as they represent the actors where implementation occurs. Specifically, our findings demonstrate how optimal goose hunting can be practiced by the use of an adaptive framework with active stakeholder participation.

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Prey Body Size and Ranking in Zooarchaeology: Theory, Empirical Evidence, and Applications from the Northern Great Basin

American Antiquity ◽

10.7183/0002-7316.76.3.403 ◽

2011 ◽

Vol 76 (3) ◽

pp. 403-428 ◽

Cited By ~ 56

Author(s):

Jack M. Broughton ◽

Michael D. Cannon ◽

Frank E. Bayham ◽

David A. Byers

Keyword(s):

Body Size ◽

Great Basin ◽

Diet Breadth ◽

Foraging Theory ◽

Return Rate ◽

The Body ◽

Foraging Efficiency ◽

Large Prey ◽

Abundance Indices ◽

Game Hunting

The use of body size as an index of prey rank in zooarchaeology has fostered a widely applied approach to understanding variability in foraging efficiency. This approach has, however, been critiqued—most recently by the suggestion that large prey have high probabilities of failed pursuits. Here, we clarify the logic and history of using body size as a measure of prey rank and summarize empirical data on the body size-return rate relationship. With few exceptions, these data document strong positive relationships between prey size and return rate. We then illustrate, with studies from the Great Basin, the utility of body size-based abundance indices (e.g., the Artiodactyl Index) when used as one component of multidimensional analyses of prehistoric diet breadth. We use foraging theory to derive predictions about Holocene variability in diet breadth and test those predictions using the Artiodactyl Index and over a dozen other archaeological indices. The results indicate close fits between the predictions and the data and thus support the use of body size-based abundance indices as measures of foraging efficiency. These conclusions have implications for reconstructions of Holocene trends in large game hunting in western North America and for zooarchaeological applications of foraging theory in general.

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