Nestling testosterone is associated with begging behaviour and fledging success in the pied flycatcher, Ficedula hypoleuca

Animal signals are hypothesized to be costly in order to honestly reflect individual quality. Offspring solicitation signals given by nestling birds are thought to have evolved to advertise either need or individual quality. We tested the potential role of testosterone (T) in controlling the intensity of these signals by measuring begging behaviour as: (i) duration of the begging display and (ii) maximum height of the begging stretch, and by sampling endogenous T levels in nestling blood. We tested nestling pied flycatchers (Ficedula hypoleuca) using well-established experimental paradigm involving transient food deprivation to encourage begging behaviour and then blood-sampled nestlings at the end of these tests for T levels. Our results show that individual nestlings with the most intense begging displays had the highest circulating levels of T immediately after testing. In addition, we found substantial differences between broods in terms of circulating T. Finally, we found evidence that broods with higher levels of T showed increased fledging success, indicating a benefit for increased T production in nestlings. The potential trade-offs involved in T-mediated begging behaviour are discussed.

Prolactin, body condition and the cost of good parenting: an interyear study in a long-lived seabird, Gould's Petrel (Pterodroma leucoptera)

1. The pituitary hormone prolactin is thought to play an important role in the promotion of parental care in birds and mammals. The level of care parents provide is, however, likely to be influenced by additional factors, such as their physiological condition at the time of breeding.

2. We examined relationships between parental body condition, plasma prolactin levels and reproductive performance in Gould's Petrels (Pterodroma leucoptera), a long-lived seabird. We predicted that parental body condition would correlate positively with both prolactin level and parenting intensity, as measured by the quality of the chick they produced. We also examined the effects of parenting intensity on parental body condition and reproductive success in the subsequent breeding season.

3. Body condition of male parents positively correlated with prolactin levels at the start of their second protracted incubation bout. The body condition of both parents correlated positively with the body condition of their chick at its peak mass. However, producing a good-quality chick did not negatively affect parental body condition or reproductive success the following year.

4. These results suggest that prolactin reinforces parental behaviour in parents in good body condition, which facilitates production of good-quality chicks. Moreover, good-quality parents consistently produce good-quality chicks with no apparent trade-off to their physical condition.

Differential rates of offspring provisioning in Gould’s petrels: are better feeders better breeders?

Procellariiformes (albatrosses and petrels) must accumulate substantial energy reserves to sustain them while incubating their single egg. They then produce a chick that is often more than 130% of their own body mass. Thus, despite the variable nature of resource availability in the marine environment, successful reproduction requires a considerable increase in foraging rates. Birds that are better foragers are, therefore, likely to be better parents. As surrogates of foraging ability, we assessed two parental traits that are separated temporally over the breeding season, body condition during incubation and provisioning performance, in Gould’s petrel (Pterodroma leucoptera). Although parental condition did not influence hatching success, we found significant positive correlations between the average body condition of a breeding pair and both the growth rate of chicks (g day^–1) and the body condition of chicks at peak mass. Provisioning rate also correlated positively with chick condition. Chick condition was positively correlated with haemoglobin concentration [Hb] at peak mass, which was positively correlated with [Hb] at fledging. Because the probability of survival after fledging may be influenced by chick body condition and [Hb], the ability of parents to acquire additional resources for breeding is likely to be an important determinant of reproductive success.

Understanding success in indigenous entrepreneurship : an exploratory investigation

In Canada there are numerous studies about indigenous Entrepreneurship, most descriptive with little theory development or testing, This leaves a gap in the information available to researchers, policy makers and practitioners. In this paper we describe a research program intended to address this gap beginning with the activities of the Lac La Ronge Indian Band, considered an exemplar of successful indigenous entrepreneurship. From these activities, we draw propositions about indigenous entrepreneurship that are compatible with generic theory. Finally, we describe how we will move from these propositions to a model of indigenous entrepreneurship using grounded theory and structural equation modelling.