Changes in sensitivity of the canary brood patch during the natural breeding season

Concentrations of prolactin were measured in the plasma of male and female canaries serially sampled during repeated breeding cycles. Concentrations in female canaries were low during nest building and increased significantly (P less than 0.05) during the first few days of incubation. Levels increased further (P less than 0.01) in the middle of the incubation period to reach concentrations which were ten times higher than before breeding. Levels remained high for several days after the eggs hatched, as the young were fed in the nest. Prolactin concentrations declined gradually as the young were reared, reaching basal levels by the time the young were fledged, but always increased again in the females as they began incubating eggs in subsequent breeding cycles. Male canaries, which do not incubate but do assist in feeding the young, showed only slight increases in prolactin during the parental period. Male and female canaries which did not breed had low levels of prolactin throughout the experiment. The results show that prolactin secretion is high not only during incubation but also during the parental feeding phase in an altricial passerine bird. These findings are discussed in relation to the different patterns of prolactin secretion which occur during breeding in other birds.

Section: Discussionmentioning

confidence: 99%

Plasma concentrations of prolactin during incubation and parental feeding throughout repeated breeding cycles in canaries (Serinus canarius)

Goldsmith¹

1982

“…Changes in the threshold of tactile sensitivity in the brood patch area of the experi¬ mental groups. The threshold was measured on the aesthesiometer scale (see Hinde, Bell & Steel, 1963). See Fig.…”

Section: Weeksmentioning

confidence: 99%

“…Brood patch formation in passerine birds, which occurs around the time of egglaying, involves defeathering and vascularization of the ventral apterium (Bailey, 1952) and an increase in its tactile sensitivity (Hinde, Bell & Steel, 1963). Previous experiments (Bailey, 1952;Hinde & Steel, 1964;Selander & Yang, 1966) indicate that:…”

Section: Introductionmentioning

confidence: 98%

The Effects of Oestrogen, Progesterone and Prolactin on Brood Patch Formation in Ovariectomized Canaries

Hutchison¹,

Hinde²,

Steel³

1967

Self Cite

The effects of certain exogenous hormones on the brood patch of ovariectomized canaries during the non-breeding season are described.Defeathering and vascularity of the brood patch were produced by oestrogen alone and by combinations of oestrogen and progesterone or prolactin, but not by progesterone or prolactin alone. The development of vascularity varied with the dose level of oestrogen: a dose of 0\m=.\2 mg. oestrogen produced stage 3 vascularity, which normally occurs at the time of egg-laying. There was a significant fall in the tactile sensitivity threshold of the brood patch in females treated with oestrogen and progesterone, and in one group treated with progesterone alone. All other groups showed no significant changes.Oestrogen alone and in combination with progesterone and prolactin caused increase in oviduct weight.These results confirm the view derived from experiments with intact canaries that oestrogen produces vascularity, but that combinations of oestrogen and prolactin or possibly progesterone are necessary for defeathering. In addition these experiments indicate that oestrogen and progesterone are necessary for a change in sensitivity threshold of the brood patch.

“…nest-building) behaviour (Warren & Hinde, 1961;Hinde & Steel, 1962). In conformity with this, the ventral surface becomes more sensitive to tactile stimulation as the reproductive season advances (Hinde, Bell & Steel, 1963). Vascularization of the brood patch can be induced by exogenous oestradiol benzoate and defeathering by this oestrogen in combination with either progesterone or prolactin .…”

Section: Introductionmentioning

confidence: 96%

Effect of Exogenous Hormones on the Tactile Sensitivity of the Canary Brood Patch

Hinde¹,

Steel²

1964

Self Cite