A DNA test to sex most birds.

We review the concepts and research associated with measuring fear and its consequences for foraging. When foraging, animals should and do demand hazardous duty pay. They assess a foraging cost of predation to compensate for the risk of predation or the risk of catastrophic injury. Similarly, in weighing foraging options, animals tradeoff food and safety. The foraging cost of predation can be modelled, and it can be quantitatively and qualitatively measured using risk titrations. Giving-up densities (GUDs) in depletable food patches and the distribution of foragers across safe and risky feeding opportunities are two frequent experimental tools for titrating food and safety. A growing body of literature shows that: (i) the cost of predation can be big and comprise the forager’s largest foraging cost, (ii) seemingly small changes in habitat or microhabitat characteristics can lead to large changes in the cost of predation, and (iii) a forager’s cost of predation rises with risk of mortality, the forager’s energy state and a decrease in its marginal value of energy. In titrating for the cost of predation, researchers have investigated spatial and temporal variation in risk, scale-dependent variation in risk, and the role of predation risk in a forager’s ecology. A risk titration from a feeding animal often provides a more accurate behavioural indicator of predation risk than direct observations of predator-inflicted mortality. Titrating for fear responses in foragers has some well-established applications and holds promise for novel methodologies, concepts and applications. Future directions for expanding conceptual and empirical tools include: what are the consequences of foraging costs arising from interference behaviours and other sources of catastrophic loss? Are there alternative routes by which organisms can respond to tradeoffs of food and safety? What does an animal’s landscape of fear look like as a spatially explicit map, and how do various environmental factors affect it? Behavioural titrations will help to illuminate these issues and more.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1461-0248.2004.00661.x

Hazardous duty pay and the foraging cost of predation

Testing the immunocompetence handicap hypothesis: A review of the evidence

Sexual selection in females

Predation risk\" and \"fear\" are concepts well established in animal behavior literature. We expand these concepts to develop the model of the \"landscape of fear\". The landscape of fear represents relative levels of predation risk as peaks and valleys that reflect the level of fear of predation a prey experiences in different parts of its area of use. We provide observations in support of this model regarding changes in predation risk with respect to habitat types, and terrain characteristics. We postulate that animals have the ability to learn and can respond to differing levels of predation risk. We propose that the landscape of fear can be quantified with the use of well documented existing methods such as giving- up densities, vigilance observations, and foraging surveys of plants. We conclude that the landscape of fear is a useful visual model and has the potential to become a unifying ecological concept.

/pdf/the-landscape-of-fear-ecological-implications-of-being-3av2mhurxm.pdf

The Landscape of Fear: Ecological Implications of Being Afraid~!2009-09-09~!2009-11-16~!2010-02-02~!

Birds are constantly responding to stimuli from their environment. When these stimuli are perceived as threatening, stress responses are initiated, with activation of the hypothalamo-pituitary-adrenal axis and the release of corticosterone from the adrenal gland. The basic emotion of fear is also experienced during a stress response. Corticosterone stress responses and behavioural responses to stimuli vary markedly between individual birds, raising questions about the significance of these individual differences and about the relationship between corticosterone responses and fearfulness in birds. Although fearfulness can be challenging to measure, data from several species indicate that corticosterone responses and fear behaviour responses are linked in individual birds. Consistent profiles of behavioural responses of birds to a wide range of stimuli can be identified and are called personalities. Personalities vary along a continuum, but are usually classified as proactive or reactive. Individual corticosterone and behaviour responses depend on each bird’s personality. Birds with proactive personalities have relatively active behavioural responses and relatively low corticosterone stress responses, whilst birds with reactive personalities have relatively passive behavioural responses and large corticosterone responses. Relationships between the physiological and behavioural characteristics of avian personalities can now be explored in detail to determine the significance of individual differences in stress responses and personalities in birds.

Stress, corticosterone responses and avian personalities

Individual variation in glucocorticoid stress responses in animals.

Sight of a Predator Can Stimulate a Corticosterone Response in the Great Tit (Parus major)

Variation within and between birds in corticosterone responses of great tits (Parus major).

1. Physiological and behavioural measures of stress in caged hens on a commercial farm were compared between White Leghorn and brown Hyline strains, and between three tiers of cages. 2. Blood and faecal samples were collected from undisturbed birds for corticosterone measurements. Plasma corticosterone responses to a stressor were measured by the collection of blood samples after 15, 30, and 60 min of a handling stressor. Tonic immobility and novel object tests were used to measure fear behaviour. 3. Plasma corticosterone in undisturbed hens and faecal corticosterone did not differ between White Leghorn and brown Hyline hens, whereas the plasma corticosterone response to a handling stressor was greater in White Leghorns. The duration of tonic immobility, latency to first head movement and number of head movements in tonic immobility tests were greater in white than brown birds, whereas the number of inductions was less for tonic immobility tests. There were no differences between the strains in their resp...

John F. Cockrem

Papers

Stress, corticosterone responses and avian personalities

Individual variation in glucocorticoid stress responses in animals.

Sight of a Predator Can Stimulate a Corticosterone Response in the Great Tit (Parus major)

Variation within and between birds in corticosterone responses of great tits (Parus major).

Corticosterone and fear behaviour in white and brown caged laying hens.