scholarly journals Measuring Annual Reproductive Success in Birds

The Condor ◽  
2000 ◽  
Vol 102 (2) ◽  
pp. 470-473 ◽  
Author(s):  
Bertram G. Murray
Keyword(s):  
Reproductive Success ◽  
Clutch Size ◽  
Breeding Season ◽  
Nest Success ◽  
Simulated Data ◽  
Evolutionary Success

Abstract From simulated data on three populations, I calculate different measures of “reproductive success”: clutch size, egg success (the proportion of eggs that produce young), nest success (the proportion of clutches that produce young), and the annual reproductive success per female in terms of both number of broods and number of young reared successfully during a breeding season. These measures of success are not correlated. Differences in egg success or nest success do not necessarily translate into differences in annual reproductive success, and differences in annual reproductive success do not necessarily translate into evolutionary success.

Clutch Size, Reproductive Success, and Organochlorine Contaminants in Atlantic Coast Black-Crowned Night-Herons

The Auk ◽  
1983 ◽  
Vol 100 (3) ◽  
pp. 699-710 ◽  
Author(s):  
Thomas W. Custer ◽  
Gary L. Hensler ◽  
T. Earl Kaiser
Keyword(s):  
North Carolina ◽  
Reproductive Success ◽  
New England ◽  
Clutch Size ◽  
Nest Success ◽  
Atlantic Coast ◽  
Similar Data ◽  
Nycticorax Nycticorax ◽  
The North ◽  
The Impact

Abstract In 1979, we gathered clutch-size and reproductive-success data on Black-crowned Night-Herons (Nycticorax nycticorax) nesting in three New England and two North Carolina colonies. In 1975, we gathered similar data from one of the New England and one of the North Carolina colonies. Latitudinal differences in clutch initiation were not evident. Mean clutch size was larger in the New England than in the North Carolina colonies. Mean clutch size was smaller in late nests from one New England colony studied in both years and another New England colony studied in 1979; seasonal trends in clutch size for other colonies were not found. In 1979, nest success was greater in two New England colonies than in one North Carolina colony. Within-season differences in nest success occurred but were inconsistent among colonies. In the four instances where statistical comparisons could be made, larger clutches were more successful than smaller ones in two colonies; large and small clutches had similar success in two other colonies. One egg was collected from each of several nests in each colony in 1979 for organochlorine contaminant analysis, and the fate of the remaining eggs was recorded. Concentrations of DDE and PCBs did not differ with clutch size; concentrations of PCBs were lower, however, in eggs laid late in the season. Although the data suggest an effect of DDE on hatching success in the northern more contaminated colonies, the impact of environmental contaminants on overall reproductive success appears to be minimal.

Follicle ablation increases offspring size in a lizard with a low clutch frequency

2009 ◽  
Vol 30 (3) ◽  
pp. 361-366 ◽  
Author(s):  
Xiang Ji ◽  
Yuan Xia ◽  
Zheng Wang
Keyword(s):  
Reproductive Success ◽  
Clutch Size ◽  
Breeding Season ◽  
Egg Size ◽  
Offspring Size ◽  
Offspring Number ◽  
Available Energy ◽  
Lacertid Lizard ◽  
Individual Offspring ◽  
High Fraction

AbstractStudies of lizards and snakes have shown that an experimental reduction of offspring number sometimes, but not always, results in an increase in offspring size. We applied the “follicle ablation” technique to an oviparous lacertid lizard (Eremias argus) to test the hypothesis that offspring size can be easily altered by manipulating clutch size in species with a low clutch frequency. Our manipulation of clutch size had the effect of inducing variation in egg size in the first post-surgical clutch, with follicle-ablated females producing fewer larger eggs than did controls. Follicle-ablated females produced a second post-surgical clutch as normally as did controls. The proportional amount of resources allocated to reproduction did not shift seasonally in E. argus, but females normally switched from producing a larger number of smaller eggs early in the breeding season to a smaller number of larger eggs later in the season. Females used in this study never produce more than two clutches per breeding season. Therefore, our data validate the hypothesis tested. Our data also provide an inference that maximization of reproductive success could be achieved in females of E. argus by diverting a larger enough, rather than an extraordinarily high, fraction of the available energy to individual offspring in single reproductive episodes.

scholarly journals Temporal changes in reproductive success and optimal breeding decisions in a long-distance migratory bird

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Cynthia Reséndiz-Infante ◽  
Gilles Gauthier
Keyword(s):  
Reproductive Success ◽  
Clutch Size ◽  
Environmental Changes ◽  
Migratory Bird ◽  
Laying Date ◽  
Negative Consequences ◽  
Breeding Phenology ◽  
Additional Time ◽  
Long Distance ◽  
Seasonal Decline

AbstractMany avian migrants have not adjusted breeding phenology to climate warming resulting in negative consequences for their offspring. We studied seasonal changes in reproductive success of the greater snow goose (Anser caerulescens atlantica), a long-distance migrant. As the climate warms and plant phenology advances, the mismatch between the timing of gosling hatch and peak nutritive quality of plants will increase. We predicted that optimal laying date yielding highest reproductive success occurred earlier over time and that the seasonal decline in reproductive success increased. Over 25 years, reproductive success of early breeders increased by 42%, producing a steeper seasonal decline in reproductive success. The difference between the laying date producing highest reproductive success and the median laying date of the population increased, which suggests an increase in the selection pressure for that trait. Observed clutch size was lower than clutch size yielding the highest reproductive success for most laying dates. However, at the individual level, clutch size could still be optimal if the additional time required to acquire nutrients to lay extra eggs is compensated by a reduction in reproductive success due to a delayed laying date. Nonetheless, breeding phenology may not respond sufficiently to meet future environmental changes induced by warming temperatures.

scholarly journals Effects of management decisions on genetic evaluation of simulated calving records using random regression

2021 ◽  
Author(s):  
M D MacNeil ◽  
J W Buchanan ◽  
M L Spangler ◽  
E Hay
Keyword(s):  
Reproductive Success ◽  
Simulated Data ◽  
Genetic Evaluation ◽  
Random Regression ◽  
Management Decisions ◽  
Third Order ◽  
Data Set ◽  
Binary Phenotype ◽  
Random Regression Model ◽  
Missing Observation

Abstract The objective of this study was to evaluate the effects of various data structures on the genetic evaluation for the binary phenotype of reproductive success. The data were simulated based on an existing pedigree and an underlying fertility phenotype with a heritability of 0.10. A data set of complete observations was generated for all cows. This data set was then modified mimicking the culling of cows when they first failed to reproduce, cows having a missing observation at either their second or fifth opportunity to reproduce as if they had been selected as donors for embryo transfer, and censoring records following the sixth opportunity to reproduce as in a cull-for-age strategy. The data were analyzed using a third order polynomial random regression model. The EBV of interest for each animal was the sum of the age-specific EBV over the first 10 observations (reproductive success at ages 2-11). Thus, the EBV might be interpreted as the genetic expectation of number of calves produced when a female is given ten opportunities to calve. Culling open cows resulted in the EBV for 3 year-old cows being reduced from 8.27 ± 0.03 when open cows were retained to 7.60 ± 0.02 when they were culled. The magnitude of this effect decreased as cows grew older when they first failed to reproduce and were subsequently culled. Cows that did not fail over the 11 years of simulated data had an EBV of 9.43 ± 0.01 and 9.35 ± 0.01 based on analyses of the complete data and the data in which cows that failed to reproduce were culled, respectively. Cows that had a missing observation for their second record had a significantly reduced EBV, but the corresponding effect at the fifth record was negligible. The current study illustrates that culling and management decisions, and particularly those that impact the beginning of the trajectory of sustained reproductive success, can influence both the magnitude and accuracy of resulting EBV.

scholarly journals Weather conditions explain reproductive success and advancement of the breeding season in Western Capercaillie ( Tetrao urogallus )

Ibis ◽  
2021 ◽  
Author(s):  
Joy Coppes ◽  
Jim‐Lino Kämmerle ◽  
Karl‐Eugen Schroth ◽  
Veronika Braunisch ◽  
Rudi Suchant
Keyword(s):  
Reproductive Success ◽  
Breeding Season ◽  
Weather Conditions ◽  
Tetrao Urogallus

Breeding season and clutch size of Indian passerines

Ibis ◽  
2008 ◽  
Vol 142 (1) ◽  
pp. 75-81 ◽  
Author(s):  
PRAMOD PADMANABHAN ◽  
YORAM YOM-TOV
Keyword(s):  
Clutch Size ◽  
Breeding Season

Not only big bulls. Correlation between morphometry, reproductive success, and testosterone level in a flooded savannah population of the spectacled caiman (Caiman crocodilus)

2021 ◽  
Author(s):  
Leidy Alejandra Barragan Contreras ◽  
Rafael Antelo ◽  
Adolfo Amezquita
Keyword(s):  
Reproductive Success ◽  
Breeding Season ◽  
Steroid Hormone ◽  
Multiple Paternity ◽  
Adult Males ◽  
Behavioral Traits ◽  
Testosterone Levels ◽  
Caiman Crocodilus ◽  
Paternity Tests ◽  
Hourly Basis

Testosterone is a steroid hormone involved in the expression of many morphological, physiological, and behavioral traits that arguably affect reproductive success. The evidence for that link is, however, incomplete or absent in the research on crocodylian species. Testosterone levels are also known to change throughout the breeding season, often on an hourly basis, which may further complicate studying their relationship with breeding success. We tested here whether baseline testosterone levels, measured out of the breeding season, are correlated with morphometry and reproductive success in Caiman crocodilus (LINNAEUS, 1758). Paternity tests, based on the amplification and genotyping of eight fluorochrome labeled microsatellites, failed to support a continuous relationship between these variables. Although adult males of all sizes contribute to reproduction, paternity was overrepresented in a few males with high values of maleness index (bigger males), supporting a despotic or pyramidal hierarchy among males. Maternity assignments supported the existence of multiple paternity, a phenomenon previously attributed in this species to the lack of large males caused by human hunting. The idea of larger males having more offspring is widespread in crocodylians, but to our knowledge, this is the first investigation that prove this dogma.

Energy Expenditure in Reproductive Effort of Male and Female Killdeer (Charadrius vociferus)

The Auk ◽  
1988 ◽  
Vol 105 (3) ◽  
pp. 553-564 ◽  
Author(s):  
Dianne H. Brunton
Keyword(s):  
Reproductive Success ◽  
Energy Expenditure ◽  
Parental Care ◽  
Breeding Season ◽  
Reproductive Effort ◽  
Mating Effort ◽  
Parental Effort ◽  
Nest Failure ◽  
Male And Female ◽  
Charadrius Vociferus

Abstract The reproductive investment strategies of the sexes during the breeding season are detailed for Killdeer (Charadrius vociferus), a monogamous plover. I measured the energy investments of the sexes in reproductive, mating, and parental effort. As predicted, males expend more mating effort than females; however, the sexes expend equal amounts of parental effort. Total energy expenditure in reproductive effort (mating and parental effort) during a successful nesting attempt was also equal for the sexes. However, early parental effort expenditures by females, early mating effort expenditures by males, and high rates of nest failure combine to result in female reproductive energy expenditures being significantly higher over the breeding season. This suggests that energy expenditure alone is not adequate for accurate comparisons of the relative investments of the sexes. Studies investigating male and female investments need to consider the degree and pattern of nest failures along with patterns of energy expenditure. The advantages to male and female Killdeer of sharing parental care is demonstrated using adult removal experiments. In general, a deserted parent expends more energy in parental effort than a bi-parental parent and has significantly lower reproductive success. However, males are able to hatch chicks, whereas females lose or abandon their nests within a few days of mate removal. Thus, monogamy in Killdeer appears to result from high nest failure rates, the necessity of two parents for any reproductive success, and the generalizable nature of Killdeer parental care.

scholarly journals How Many Baskets? Clutch Sizes That Maximize Annual Fecundity of Multiple-Brooded Birds

The Auk ◽  
2001 ◽  
Vol 118 (4) ◽  
pp. 973-982 ◽  
Author(s):  
George L. Farnsworth ◽  
Theodore R. Simons ◽  
J. Brawn
Keyword(s):  
Clutch Size ◽  
Breeding Season ◽  
Nest Predation ◽  
Reproductive Effort ◽  
Nest Survival ◽  
Survival Rates ◽  
Season Length ◽  
Deterministic Models ◽  
Cavity Nesting ◽  
Theoretical Issues

Abstract We developed deterministic models on the basis of nest survival rates and renesting behavior capable of predicting annual fecundity in birds. The models calculate probabilities of fledging from one to four nests within a discrete breeding season. We used those models to address theoretical issues related to clutch size. In general, birds require at least one day to lay an egg, and many species delay incubation until their entire clutch is laid. Because it takes longer to complete a larger clutch, and fewer such clutches can fit into a limited breeding season, there exists a clutch size for which annual fecundity is maximized. We asked, for a given amount of reproductive effort (i.e. a set number of eggs), does the age-old maxim “don't put all your eggs in one basket” apply? If so, in how many “baskets” should a nesting bird place its eggs? The answer depends on both likelihood of nest predation and length of the breeding season. Those results are consistent with the observed increase in clutch size with latitude (shorter breeding season length) and larger clutch sizes characteristic of cavity-nesting species (with higher nest survival rates). The models also predict that the size of replacement clutches should decrease as the breeding season progresses, and that intraseasonal decline in clutch size should be more pronounced when the breeding season is short.

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