Sex Ratio Of Chicks Research Articles

Natal habitat and sex-specific survival rates result in a male-biased adult sex ratio.

The adult sex ratio (ASR) is a crucial component of the ecological and evolutionary forces shaping the dynamics of a population. Although in many declining populations ASRs have been reported to be skewed, empirical studies exploring the demographic factors shaping ASRs are still rare. In this study of the socially monogamous and sexually dimorphic Black-tailed Godwit (Limosa limosa limosa), we aim to evaluate the sex ratio of chicks at hatch and the subsequent sex-specific survival differences occurring over 3 subsequent life stages. We found that, at hatch, the sex ratio did not deviate from parity. However, the survival of pre-fledged females was 15–30% lower than that of males and the sex bias in survival was higher in low-quality habitat. Additionally, survival of adult females was almost 5% lower than that of adult males. Because survival rates of males and females did not differ during other life-history stages, the ASR in the population was biased toward males. Because females are larger than males, food limitations during development or sex-specific differences in the duration of development may explain the lower survival of female chicks. Differences among adults are less obvious and suggest previously unknown sex-related selection pressures. Irrespective of the underlying causes, by reducing the available number of females in this socially monogamous species, a male-biased ASR is likely to contribute to the ongoing decline of the Dutch godwit population.

Evidence for an additive effect of hunting mortality in an alpine black grouse Lyrurus tetrix population

In the Canton of Ticino in southern Switzerland data from the monitoring programme for black grouse from 1981 to 2016 (population density, lek size, sex ratio in chicks and adults) were analysed together with information on bag statistics and hunting regulations to evaluate if mortality from hunting had an additive effect. In the study population the proportion of cocks at the beginning of the study period was only 23%. As hunting regulations for black grouse were tightened in the late 1970s the observed proportion of males showed an increase in particular during the first years but remained much lower than what would be expected from the sex ratio among chicks assuming equal survival between the sexes. The observed low proportion of adult males indicates a lower survival rate and as a consequence a smaller than natural lek size. High reproductive success two years before had a positive effect on lek size. The correlation coefficient between hunting bag and population size index increased with increasing hunting pressure and showed a decline over the years. Bag size in the period with a high hunting pressure (1981–1999, many hunting days) was driven by population density whereas in the second period (2000–2016, few hunting days) it was driven by hunting regulations. Our analysis showed that hunting affects population structure and presents indirect evidence that mortality due to hunting is additive. The study also shows that hunting management has to be continuously adapted to changes in the size and structure of the population as well as changes in habitat conditions. It is therefore essential to continue long‐term monitoring of population size and of demographic parameters.

Sex ratio of White Stork Ciconia ciconia in different environments of Poland.

The aim of this study was to analyze the variation in sex ratio of White Stork Ciconia ciconia chicks from differentiated Poland environments. We took under a consideration the impact of Cd and Pb for establish differences among sex ratio in chicks. We also study multiplex PCR employment for establish gender considerations. We collected blood samples via venipuncture of brachial vein of chicks during 2006-2008 breeding seasons at the Odra meadows (SW-Poland; control), which were compared with those from suburbs (SW-Poland), and from copper smelter (S-Poland; polluted) and from swamps near Baltic Sea. We found differences among sex ratio in White Stork chicks from types of environment. Male participation in sex structure is importantly higher in each type of environment excluded suburban areas. Differences in White Stork sex ratio according to the degree of environmental degradation expressed by Cd and Pb and sex-environment-metal interactions testify about the impact of these metals upon sex ratios in storks. Simultaneously, as a result of multiplex PCR, 18S ribosome gene, which served as internal control of PCR, was amplified in male and female storks. It means that it is possible to use primers designed for chicken in order to replicate this fragment of genome in White Stork. Moreover, the use of Oriental White Stork Ciconia boyciana W- chromosome specific primers makes it possible to determine the sex of C. ciconia chicks. Many factors make sex ratio of White Stork changes in subsequent breeding seasons, which depend significantly on specific environmental parameters that shape individual detailed defense mechanisms.

Do sex ratio and development differ in sexually size-dimorphic shiny cowbirds (Molothrus bonariensis) parasitizing smaller and larger hosts?

Fil: Tuero, Diego Tomas. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Instituto de Ecologia, Genetica y Evolucion de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecologia, Genetica y Evolucion de Buenos Aires; Argentina

Sage Grouse Chick Survival Rates in Jackson Hole

The Greater Sage-grouse (Centrocerus urophasianus) population within Jackson Hole has been declining over the past 60 years (Holloran and Anderson 2004). Currently, several unknown population parameters may affect population models, such as nesting productivity (and annual variation therein), nest initiation and re-nesting rates, sex ratio of chicks produced, chick survival, and annual sub-adult and adult survival rates. While previous research has investigated some of these demographic parameters for the Jackson Hole sage-grouse population (Holloran and Anderson 2004); those estimates may not be adequate due to sample size limitations. Further, there are new constraints on this population due to drastic changes in the wintering habitat from wildfires since those estimates were obtained.

Capercaillie Tetrao urogallus in Scotland ‐ demography of a declining population

Capercaillie Tetrao urogallus numbers declined in Scottish forests between 1992 and 1997, although the rate (mean 16% per year, 95% CL 1–30%) differed among forests. Hens declined more quickly than cocks despite the sex ratio in chicks favouring females. A probable explanation is that adult cocks lived longer. Juvenile survival was less than adult survival, largely because juveniles were more likely to die from hitting fences. Although poor reproduction was probably the main cause of the decline, this might not have occurred had fence strikes been substantially fewer.

Sex ratio of chicks in the Shag Phalacrocorax aristotelis determined by a female‐specific band in DNA fingerprinting

IbisVolume 135, Issue 4 p. 470-472 Sex ratio of chicks in the Shag Phalacrocorax aristotelis determined by a female-specific band in DNA fingerprinting J. Graves, J. Graves School of Biological and Medical Sciences, University of St Andrews, St Andrews KY16 9TS, UK.Search for more papers by this authorJ. OrtegaRuano, J. OrtegaRuano School of Biological and Medical Sciences, University of St Andrews, St Andrews KY16 9TS, UK.Search for more papers by this authorP. J. B. Slater, P. J. B. Slater School of Biological and Medical Sciences, University of St Andrews, St Andrews KY16 9TS, UK.Search for more papers by this author J. Graves, J. Graves School of Biological and Medical Sciences, University of St Andrews, St Andrews KY16 9TS, UK.Search for more papers by this authorJ. OrtegaRuano, J. OrtegaRuano School of Biological and Medical Sciences, University of St Andrews, St Andrews KY16 9TS, UK.Search for more papers by this authorP. J. B. Slater, P. J. B. Slater School of Biological and Medical Sciences, University of St Andrews, St Andrews KY16 9TS, UK.Search for more papers by this author First published: October 1993 https://doi.org/10.1111/j.1474-919X.1993.tb02124.xCitations: 7AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume135, Issue4October 1993Pages 470-472 RelatedInformation

Sex Ratios of Prefledging Western Gulls

Western Gull (Larus occidentalis) chicks on Santa Barbara Island, California, had a sex ratio at hatching of 1.12 M/F (n = 609); the sex ratio of chicks ≥35 days of age was 0.89 (n = 189). The sex ratio at hatching and fledging did not vary significantly from 1.0 or from each other, but the data suggest that male mortality before fledging exceeded that of females. Depressed growth rates of male chicks hatched third may be responsible for these higher male mortality rates. We found no evidence for seasonal or hatching-order effects on sex ratios at hatching. We suggest that postfledging differences in mortality between the sexes are in part responsible for the skewed sex ratio (0.67 males/female) observed in the adult breeding population.

The Relationship between Hatching Time and Sex-ratio in Chicks

The relationship between hatching time and sex-ratio in chicks was investigated in connection with breed and age of their parents, laying season and egg size. The chicks used were 3 strains of White Leghorn (W.L.) and hybrids between Rhode Island Red (R.I.R.) male and Rhode Island White (R.I.W.) female and between W.L. male and Barred Plymouth Rock (B.P.R.) female, and the reciprocal hybrid of the latter. Chicks that hatched alive were classified according to time intervals of every 2 or 3 hours after the start of hatch and sexing was done immediately after hatch.Female chicks tended to hatch earlier than males and the difference in hatching time between males and females varied among the breeds or the strains used, especially in the hybrid between R.I.R. male and R.I.W. female.Female chicks hatched earlier than males in proportion to the increase of age of their parent stocks in the hybrid between R.I.R. male and R.I.W. female, whereas no difference was observed among the other breeds used.In general, hatching time also might be earlier during the hot season than during the cold. This was clearly shown in the R.I.R. male: R.I.W. female hybrid and the difference of hatching time between the two sexes was more distinct in the hot season than in cold in this hybrid.Large eggs tended to hatch earlier than small ones in the R.I.R. male: R.I.W. female hybrid and vice versa in the Shaver strain of W.L. Eggs of medium size showed less difference in hatching time between the two sexes than those of larger or smaller size in hybrid chicks from R.I.R. male and R.I.W. female.It might be concluded from the results that the hatching time and the sex-ratio are affected considerably by the breeds or the strains of their parents.

The Relation between the Hatching Time and the Sex-ratio in Chicks

It was reported previously by the authors that the hatching time and the sex-ratio in chicks might be affected by the breed, the age of the breeding stocks and the breeding season.The present experiments were carried out to clarify the relation between the hatching time and the sex-ratio due to the egg weight in the two different poultry farms.Three sorts of chicks were used, namely, the hybrid between Rhode Island Red (R. I. R.) males and Rhode Island White (R. I. W.) females, that between White Leghorn males and Barred Plymouth Rock (B. P. R.) females and that of the Shaver Strain of White Leghorn (W. L.).The hatching time was recorded at 3 hours intervals from the start of hatching to 36 hours thereafter, and the egg weight was classified at 2g intervals from 53g to above 65g.1. In the hybrid between R. I. R. males and R. I. W. females, and that between W. L. males and B. P. R. females, female chicks tended to hatch in the early period of hatching and male chicks tended to hatch in the late period.On the ralation between the hatching time and the sex-ratio of their chicks, the differences were recognized to be significant at 0.1% level in the former hybrids, and 1% level in the latter ones.2. With regard to the incubation period between males and females, less difference might be recognized in the standard egg weight than in large and small eggs in hybrids between R. I. R. males and R. I. W. females, and between W. L. males and B. P. R. females, in which a significant difference was exsisted between the hatching time and the sex-ratio.3. In the Shaver Strain of W. L., the considerable differences between the hatching time and the sex-ratio were found among the stocks of different age, though the difference was not significant statistically.The hatching time of the chicks from elder breeding stocks might be decreased, and it was considered to be affected by the laying season.4. From above mentioned results, it might be concluded that the hatching time and the sex-ratio in chicks are affected considerably by the breeds of their parents.

Studies on the Proliferation of Copper Pheasant (<i>Phasianus soemmerringii scintillans</i>)

It was reported previously by authors that artificial insemination was succeeded in copper pheasants. In this paper, data were collected from successing experiments performed during 5 years period (1963-1967), using 62 birds (_??_14, _??_48), on their egg laying, fertility and hatchability, sex-ratio in chicks and their growth.The results obtained were as follows:1. The mean number of eggs laying and the laying periods were 19.8 (5-40) eggs and 55. 7 (10-97) days respectively, and also considerable individual differences were observed among them. The peak production of eggs was considered to be from the middle of April to that of May, and also high fecundity was observed in 3 or 4 ages than the other age.2. The fertility and the hatchability (to fertilized eggs) in copper pheasants by using artificial insemination were 84.3% and 84.0% respectively.3. The semen was collected from the beginning of March to that of June, and also more volume of semen was collected from the middle of March to that of April. The mean volume of semen was 0.025 (0.005-0.1)ml, and 3 or 4 ages of birds were observed to be the adequate age to collect the semen.4. From these results, authors concluded that the breeding ages in copper pheasants were considered to be 3 or 4 ages, and the synchronization of the breeding season between sexes might be necessary to get the better results, for in males the breeding season was one month earlier than that of females.5. Generally speaking, female chicks were hatched more than males, and this tendency was clear in the case of mating of parents in the high fertilities. Some relation might be exsisted between the ranking of egg laying and the sex-ratio.6. On the growth of chicks, the differences were observed between sexes from 4 weeks of age.

The Relation between the Hatching Time and the Sex-Ratio in Chicks

The Relation between the Hatching Time and the Sex-Ratio in Chicks

The Relation between the Hatching Time and the Sex-Ratio in Chicks

The Relation between the Hatching Time and the Sex-Ratio in Chicks

The Relation between the Hatching Time and the Sex-Ratio in Chicks

The Relation between the Hatching Time and the Sex-Ratio in Chicks

Relation of Age of Parents to Mortality and Sex Ratio of Chicks at Eight Weeks

PHYSIOLOGICAL characters are very important in breeding poultry for egg production, viability, and disease resistance. For the most part these characters have a low degree of heritability necessitating the use of progeny testing which requires old parents for reproduction. Longevity also offers something of a measure of viability, and family mortality rate affords a useful tool to guide the breeder.This study was undertaken first to discover possible relations between age of parents and the viability of their offspring to eight weeks of age. It was desirable also to learn whether age of parents has any effect on the sex ratio of chicks at eight weeks of age. Observations on the effect of this early mortality on the sex ratio at the age of eight weeks would also be useful.LITERATURE REVIEWPearl (1940) reported the mortality rate in infants from 20 countries during the first year of life as .

Sex Ratio in Chicks at Eight Weeks and Viability

THE sex ratio of Rhode Island Red chicks in a closed flock bred for high fecundity has always shown an excess of males at eight weeks of age (Hays, 1941, 1949). Landauer and Landauer (1931) recorded the sex of 2,329 chicks that died during the first two months after hatching and found a significant excess of males. Hutt (1949) after reviewing the literature is inclined to the belief that the mortality rate in male chicks is not always greater than in females.We have observed a wide variability in the sex ratio in families of pedigreed chicks at eight weeks of age. Naturally the question arises as to whether or not these variations are associated with viability as measured by mortality rate within the family.DATA AVAILABLEThere was a total of 343 families of chicks hatched from 1938 to 1947 in a closed flock of Rhode Island Reds bred .

Embryonic Death Rate and Sex Ratio in Chicks

Embryonic Death Rate and Sex Ratio in Chicks

Embryonic death rate and sex ratio in chicks.

Embryonic death rate and sex ratio in chicks.

Complete elimination of microorganisms from an intestinal parasite (Ascaris lumbricoides).

Complete elimination of microorganisms from an intestinal parasite (Ascaris lumbricoides).

The Primary Sex Ratio in Domestic Chickens

Previous articleNext article No AccessShorter Articles and DiscussionThe Primary Sex Ratio in Domestic ChickensF. A. HaysF. A. Hays Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The American Naturalist Volume 79, Number 781Mar. - Apr., 1945 Published for The American Society of Naturalists Article DOIhttps://doi.org/10.1086/281252 Views: 3Total views on this site Citations: 10Citations are reported from Crossref PDF download Crossref reports the following articles citing this article:K.E. Collins, B.J. Jordan, B.L. McLendon, K.J. Navara, R.B. Beckstead, J.L. Wilson No evidence of temperature-dependent sex determination or sex-biased embryo mortality in the chicken, Poultry Science 92, no.1212 (Dec 2013): 3096–3102.https://doi.org/10.3382/ps.2013-03378 Sara E. Pinson , Christina M. Parr , Jeanna L. Wilson , and Kristen J. Navara Acute Corticosterone Administration during Meiotic Segregation Stimulates Females to Produce More Male Offspring, Physiological and Biochemical Zoology 84, no.33 (Jul 2015): 292–298.https://doi.org/10.1086/659373Stephanie M. Correa, Claire M. Horan, Patricia A. Johnson, Elizabeth Adkins-Regan Copulatory behaviors and body condition predict post-mating female hormone concentrations, fertilization success, and primary sex ratios in Japanese quail, Hormones and Behavior 59, no.44 (Apr 2011): 556–564.https://doi.org/10.1016/j.yhbeh.2011.02.009Kenji Ichinoe The Relationship between Hatching Time and Sex-ratio in Chicks, Poultry Science 52, no.44 (Jul 1973): 1584–1592.https://doi.org/10.3382/ps.0521584K. Sittmann, H. Abplanalp Extended Storage of Quail, Chicken, and Turkey Eggs, Poultry Science 50, no.33 (May 1971): 722–725.https://doi.org/10.3382/ps.0500722Lloyd R. Champion Sex Ratios in Two Strains of Leghorns and Their Reciprocal Crosses, Poultry Science 39, no.44 (Jul 1960): 876–881.https://doi.org/10.3382/ps.0390876WALTER LANDAUER Primary Sex Ratio of Fowl, Nature 180, no.45954595 (Nov 1957): 1139–1140.https://doi.org/10.1038/1801139a0OLE VENGE THE SEX RATIO IN FARM MINK, Acta Zoologica 34, no.33 (Sep 1953): 293–302.https://doi.org/10.1111/j.1463-6395.1953.tb00473.xF.A. Hays Sex Ratio in Chicks at Eight Weeks and Viability, Poultry Science 30, no.11 (Jan 1951): 98–99.https://doi.org/10.3382/ps.0300098F. A. Hays Sex Influence on Embryonic Death Rate in Chicks, Science 110, no.28642864 (Nov 1949): 533–533.https://doi.org/10.1126/science.110.2864.533