Vocalization of farm animals as a measure of welfare

Prolactin and parental behavior in Adélie penguins: effects of absence from nest, incubation length, and nest failure.

The roles of stimuli from young, previous breeding experience, and prolactin in regulating parental behavior in ring doves (Streptopelia risoria).

Selection should favor flexibility in reproductive tactics when the combination of sexual traits and reproductive behaviors that achieve the highest fitness differs between males within a population. Understanding the functional significance of variation in male reproductive tactics can provide insight into their evolution. Male house finches (Carpodacus mexicanus) in a Montana population display continuous variation in parental tactics: males with more elaborated (redder) plumage color provide little or no parental care compared to less elaborated (dull) males. Here, we first determined whether elevation of prolactin (a pituitary hormone) was related to variation in male parental tactics and, second, we used the relationship between prolactin levels and parental behavior to investigate why redder males avoid a high investment in parental care. We found that prolactin elevation was closely associated with paternal care. In addition, males with redder plumage color had low prolactin levels, whereas dull males, which provision twice as frequently, had high levels of prolactin. We also found that male condition was unrelated to plumage color but negatively related to prolactin levels. These results suggest that the low provisioning of redder males was not due to physiological constraints, but instead reflected a tactic to avoid the costs associated with parental care. The condition benefits accrued by redder males may explain their higher post-breeding survival compared to dull males. Moreover, dull males were previously shown to have higher pairing success than redder males, suggesting that the relationship between male plumage color and parental care may reflect individually optimized parental tactics.

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Elaborately ornamented males avoid costly parental care in the house finch (Carpodacus mexicanus): a proximate perspective

Seasonal changes in the hypothalamo-pituitary-gonadal axis in birds.

Influence of stimuli from chicks on behavior and concentrations of plasma prolactin and luteinizing hormone in incubating hens.

1. Nest and egg deprivation is a procedure traditionally used to disrupt incubation behaviour expression in commercial flocks. The aim of this study was to establish how nest deprivation affects the subsequent changes in behaviour and hormone secretion and whether readiness to renest is related to hormone concentration before and during nest deprivation. 2. Incubating broiler breeder hens were deprived of their nest either in their familiar environment, by blocking the nest entrance in the home cage or in an unfamiliar environment, by transfer in a different cage. After 3 days of nest deprivation, next access was allowed and readiness to incubate tested. 3. Both methods of nest deprivation resulted in the expression of similar behaviours associated with the disruption of incubation, and similar increases in plasma LH and oestradiol and decreases in plasma prolactin. The percentage (70%) of hens which renested after either method of nest deprivation did not differ significantly. 4. Readiness to renest was ...

Behaviour and hormone concentrations in nest deprived and renesting hens.

Two series of experiments investigated factors affecting utterance of food calls in the domestic hen, Gallus domesticus. The first series of experiments tested the effect of food preference and the hen’s internal state on the utterance of food calls. Different food types were presented first singly and then in a choice test to 20 hens, first when hens were laying, and then when they were maternal. The second series of experiments tested the effect of hunger level on the utterance of food calls in laying hens, and maternal hens with or without chicks. These two series of experiments showed that laying hens and maternal hens showed a similar marked preference for certain types of food, but laying hens very rarely emitted food calls, in contrast to maternal hens. This shows the effect of the bird’s psychophysiological state on her tendency to emit food calls. The more a maternal hen preferred a food type, the more food calls she emitted. This was observed from the beginning of a test in single-food tests as well as in choice tests. Hunger level positively affected food-call production under certain feeding conditions in maternal hens, but not in laying hens. When maternal hens were tested in the absence of their chicks, utterance of food calls was more sustained than in the presence of chicks.

Forasté M

Papers

Influence of stimuli from chicks on behavior and concentrations of plasma prolactin and luteinizing hormone in incubating hens.

Behaviour and hormone concentrations in nest deprived and renesting hens.

Internal and external factors modulate food-calling in domestic hens