• Publications
  • Influence
Yolk is a source of maternal testosterone for developing birds.
  • H. Schwabl
  • Biology, Medicine
  • Proceedings of the National Academy of Sciences…
  • 15 December 1993
The sex steroid hormones that affect development in birds have been thought to be produced exclusively by the embryo or neonate. I used radioimmunoassay to measure the amounts of androstenedione, 5Expand
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Maternal testosterone in the avian egg enhances postnatal growth.
  • H. Schwabl
  • Biology, Medicine
  • Comparative biochemistry and physiology. Part A…
  • 1 July 1996
The eggs of the canary (Serinus canaria) contain variable doses of maternal testosterone. The reported experiments investigated whether testosterone influences nestling growth and how this interactsExpand
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Hormone-mediated maternal effects in birds: mechanisms matter but what do we know of them?
Over the past decade, birds have proven to be excellent models to study hormone-mediated maternal effects in an evolutionary framework. Almost all these studies focus on the function of maternalExpand
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Environment modifies the testosterone levels of a female bird and its eggs.
  • H. Schwabl
  • Biology, Medicine
  • The Journal of experimental zoology
  • 1 October 1996
Past studies have shown that the yolk of the canary (Serinus canaria) egg contains maternal testosterone, that its concentrations increase in the subsequently formed eggs of a clutch, and thatExpand
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Yolk androgens reduce offspring survival
Females may favour some offspring over others by differential deposition of yolk hormones. In American kestrels (Falco sparverius), we found that yolks of eggs laid late in the sequence of a clutchExpand
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Determinants of within‐ and among‐clutch variation in levels of maternal hormones in Black‐Headed Gull eggs
1. Females of egg-laying vertebrates may adjust the development of their offspring to prevailing environmental conditions by regulating the deposition of hormones into their eggs. Within- andExpand
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Yolk testosterone organizes behavior and male plumage coloration in house sparrows (Passer domesticus)
Abstract Vertebrate eggs contain maternal steroid hormones in their yolks; and in avian species the concentration of these steroids vary within and among clutches. The organizational actions of theseExpand
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Orchestration of avian reproductive effort: an integration of the ultimate and proximate bases for flexibility in clutch size, incubation behaviour, and yolk androgen deposition
How much effort to expend in any one bout of reproduction is among the most important decisions made by an individual that breeds more than once. According to life‐history theory, reproduction isExpand
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The Contents of Maternal Testosterone in House Sparrow Passer domesticusEggs Vary with Breeding Conditions
  • H. Schwabl
  • Biology, Medicine
  • Naturwissenschaften
  • 1 September 1997
1. Smith, B.D.: The Emergence of Agriculture. New York: Scientific American Library 1995 2. Gibson, A., Woods, A.: Prehistoric Pottery for the Archaeologist. Leicester: Leicester University Press,Expand
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A hormonal mechanism for parental favouritism
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