scholarly journals Climatic effects on breeding grounds are more important drivers of breeding phenology in migrant birds than carry-over effects from wintering grounds

2013 ◽  
Vol 9 (6) ◽  
pp. 20130669 ◽  
Author(s):  
Nancy Ockendon ◽  
Dave Leech ◽  
James W. Pearce-Higgins
Keyword(s):  
Clutch Size ◽  
Arid Zone ◽  
Laying Date ◽  
Breeding Phenology ◽  
Spring Temperature ◽  
Climatic Effects ◽  
Long Distance ◽  
Breeding Grounds ◽  
Carry Over ◽  
The Impact

Long-distance migrants may be particularly vulnerable to climate change on both wintering and breeding grounds. However, the relative importance of climatic variables at different stages of the annual cycle is poorly understood, even in well-studied Palaearctic migrant species. Using a national dataset spanning 46 years, we investigate the impact of wintering ground precipitation and breeding ground temperature on breeding phenology and clutch size of 19 UK migrants. Although both spring temperature and arid zone precipitation were significantly correlated with laying date, the former accounted for 3.5 times more inter-annual variation. Neither climate variable strongly affected clutch size. Thus, although carry-over effects had some impact, they were weaker drivers of reproductive traits than conditions on the breeding grounds.

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.

Effects of body mass on courtship, pairing, and reproduction in captive mallards

1989 ◽  
Vol 67 (2) ◽  
pp. 495-501 ◽  
Author(s):  
R. K. Pattenden ◽  
D. A. Boag
Keyword(s):  
Clutch Size ◽  
Body Mass ◽  
Reproductive Output ◽  
Breeding Biology ◽  
Laying Date ◽  
Body Reserves ◽  
Pair Bonds ◽  
Breeding Grounds ◽  
Delayed Initiation ◽  
Nutrient Reserves

The object of this study was to examine the influence of body mass, a measure of nutrient reserves, on the breeding biology of captive mallards. Low body mass delayed initiation of courtship and pairing, and decreased the number of permanent pair bonds formed. However, pairing date was not correlated with laying date. Low body mass during winter had a greater influence on laying date than low body mass during spring, but neither affected clutch size. This suggests that an individual arriving on the breeding grounds with low body reserves relative to others will have a lower reproductive output that year.

scholarly journals Mid-winter temperatures, not spring temperatures, predict breeding phenology in the European starling Sturnus vulgaris

2015 ◽  
Vol 2 (1) ◽  
pp. 140301 ◽  
Author(s):  
Tony D. Williams ◽  
Sophie Bourgeon ◽  
Allison Cornell ◽  
Laramie Ferguson ◽  
Melinda Fowler ◽  
...  
Keyword(s):  
Clutch Size ◽  
Prey Availability ◽  
Sturnus Vulgaris ◽  
Winter Temperature ◽  
Laying Date ◽  
Breeding Phenology ◽  
European Starlings ◽  
Winter Temperatures ◽  
Lag Times ◽  
High Degree

In many species, empirical data suggest that temperatures less than 1 month before breeding strongly influence laying date, consistent with predictions that short lag times between cue and response are more reliable, decreasing the chance of mismatch with prey. Here we show in European starlings ( Sturnus vulgaris ) that mid-winter temperature ca 50–90 days before laying (8 January–22 February) strongly ( r 2 = 0.89) predicts annual variation in laying date. Mid-winter temperature also correlated highly with relative clutch size: birds laid later, but laid larger clutches, in years when mid-winter temperatures were lower. Despite a high degree of breeding synchrony (mean laying date 5–13 April = ±4 days; 80% of nests laid within 4.8 days within year), European starlings show strong date-dependent variation in clutch size and productivity, but this appears to be mediated by a different temporal mechanism for integration of supplemental cue (temperature) information. We suggest the relationship between mid-winter temperature and breeding phenology might be indirect with both components correlating with a third factor: temperature-dependent development of the starling's insect (tipulid) prey. Mid-winter temperatures might set the trajectory of growth and final biomass of tipulid larvae, with this temperature cue providing starlings with information on breeding season prey availability (though exactly how remains unknown).

Statistical Translation After Source Reordering: Oracles, Context-Aware Models, and Empirical Analysis

2012 ◽  
Vol 18 (4) ◽  
pp. 491-519 ◽  
Author(s):  
MAXIM KHALILOV ◽  
KHALIL SIMA'AN
Keyword(s):  
Word Order ◽  
Target Sentence ◽  
Training Data ◽  
Translation System ◽  
Long Distance ◽  
Translation Model ◽  
Unseen Data ◽  
Carry Over ◽  
Set Up ◽  
The Impact

AbstractIn source reordering the order of the source words is permuted to minimize word order differences with the target sentence and then fed to a translation model. Earlier work highlights the benefits of resolving long-distance reorderings as a pre-processing step to standard phrase-based models. However, the potential performance improvement of source reordering and its impact on the components of the subsequent translation model remain unexplored. In this paper we study both aspects of source reordering. We set up idealized source reordering (oracle) models with/without syntax and present our own syntax-driven model of source reordering. The latter is a statistical model of inversion transduction grammar (ITG)-like tree transductions manipulating a syntactic parse and working with novel conditional reordering parameters. Having set up the models, we report translation experiments showing significant improvement on three language pairs, and contribute an extensive analysis of the impact of source reordering (both oracle and model) on the translation model regarding the quality of its input, phrase-table, and output. Our experiments show that oracle source reordering has untapped potential in improving translation system output. Besides solving difficult reorderings, we find that source reordering creates more monotone parallel training data at the back-end, leading to significantly larger phrase tables with higher coverage of phrase types in unseen data. Unfortunately, this nice property does not carry over to tree-constrained source reordering. Our analysis shows that, from the string-level perspective, tree-constrained reordering might selectively permute word order, leading to larger phrase tables but without increase in phrase coverage in unseen data.

scholarly journals Warmer springs, laying date and clutch size of tree sparrows Passer montanus in Croatia

2011 ◽  
Vol 57 (3) ◽  
pp. 414-418 ◽  
Author(s):  
Z. Dolenec ◽  
P. Dolenec ◽  
A.P. Møller
Keyword(s):  
Clutch Size ◽  
Laying Date ◽  
Negative Effects ◽  
Spring Temperature ◽  
Temperature Changes ◽  
Passer Montanus ◽  
Air Temperatures ◽  
Socially Monogamous ◽  
Extreme Change

Abstract Global surface air temperatures increased during the past 100 years. Many long-term studies of birds have reported a climatic influence on breeding performance. We analysed long-term changes in first laying date and clutch size for first clutches of sedentary, hole-nesting and socially monogamous tree sparrows Passer montanus during 1980–2009 in northwestern Croatia. Laying date advanced and spring temperature increased significantly during the study. Date of laying was significantly correlated with mean air spring temperature and advanced by 8.6 days during the 30 years period. Laying date was delayed in extremely cold, but not in extremely warm springs compared to years with normal temperatures. These results suggest that current climate change including extreme change does not have negative effects on timing of laying or clutch size. In contrast to laying date, clutch size did not vary systematically during the study period or with mean spring air temperature changes.

Habitat ecology of Nearctic–Neotropical migratory landbirds on the nonbreeding grounds

The Condor ◽  
2020 ◽  
Author(s):  
Steven Albert ◽  
Jared D Wolfe ◽  
Jherime Kellerman ◽  
Thomas Sherry ◽  
Bridget J M Stutchbury ◽  
...  
Keyword(s):  
Population Change ◽  
Bird Species ◽  
Population Trends ◽  
Neotropical Migrants ◽  
Long Distance ◽  
Wintering Grounds ◽  
Phenological Mismatch ◽  
Critical Issues ◽  
Breeding Grounds ◽  
Carry Over

Abstract Of the approximately 716 bird species that breed in North America, 386 (54%) are considered Nearctic–Neotropical migrants by the U.S. Fish and Wildlife Service. In the past 50 yr, scores of these migratory species, including some once considered common, have declined dramatically. Nearctic–Neotropical migrants normally spend 6–8 months in tropical habitats, making the identification, availability, and management of Neotropical habitats critical issues for their conservation. Yet, for most species, complete and nuanced information about their use of tropical habitats and the relative effects of breeding vs. wintering conditions on survival, productivity, and population trends is not available, though many studies point to Neotropical overwintering habitats as being a strong driver of population change. Particularly important for long-distance Nearctic–Neotropical migrants is an understanding of how “carry-over effects” arise and influence population trends when conditions on wintering grounds and tropical stopover areas affect subsequent reproductive performance on breeding grounds. For example, why some species show strong carry-over effects from tropical habitats while others do not is not fully understood. In recent years, many studies have offered insights into these issues by taking advantage of new scientific methods and technological innovations. In this review, we explore threats facing North American breeding birds that migrate to the Neotropics, summarize knowledge of habitat selection and use on the wintering grounds, describe how conditions at one point in the annual cycle may manifest in subsequent seasons or life history stages, and discuss conservation concerns such as climate change and the potential for phenological mismatch.

scholarly journals Clutch Enlargement in Lesser Gray Shrikes (Lanius Minor) in Slovakia When Food is Superabundant: A Maladaptive Response?

The Auk ◽  
2004 ◽  
Vol 121 (2) ◽  
pp. 557-564
Author(s):  
Herbert Hoi ◽  
Anton Kristin ◽  
Francisco Valera ◽  
Christine Hoi
Keyword(s):  
Clutch Size ◽  
Egg Laying ◽  
Laying Date ◽  
Breeding Ecology ◽  
Long Distance ◽  
Fledging Success ◽  
Melolontha Melolontha ◽  
Nestling Diet ◽  
Study Population ◽  
Maladaptive Response

Abstract Food abundance influences various aspects of birds' breeding ecology, such as onset of laying, clutch size, and reproductive success. Here, we examine the effects of a natural superabundance of food—cockchafers (Melolontha melolontha, Coleoptera)—on nesting success of a monogamous long-distance migrant, the Lesser Gray Shrike (Lanius minor). In that species, cockchafers make up 88% of adult and 48% of nestling diet in years with cockchafer outbreaks. We compared timing of egg laying, clutch size, and fledging success in three years and chick development in two years with and without cockchafer outbreaks. In cockchafer years, laying date was advanced by about one day, clutch size increased by about one egg, and heavier chicks were produced. Fledging success, however, did not change (fledgling number in non-cockchafer years: 5.3 ± 0.2, 5.0 ± 0.2, and 4.0 ± 0.5; in cockchafer years: 4.1 ± 0.7, 5.4 ± 0.2, and 4.2 ± 0.5), because more eggs failed to hatch during cockchafer years. Thus, increased clutch size in periods of superabundant food do not always result in increased fledgling production. Limited incubation ability or intrinsic physical egg properties, resulting in inefficient incubation, are the most likely explanations for increased hatching failure in years of food superabundance in our study population of Lesser Gray Shrikes.

scholarly journals Linking migratory performance to breeding phenology and productivity in an Afro-Palearctic long-distance migrant

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Joana S. Costa ◽  
Steffen Hahn ◽  
Pedro M. Araújo ◽  
Kiran L. Dhanjal-Adams ◽  
Afonso D. Rocha ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Laying Date ◽  
Breeding Phenology ◽  
Migratory Species ◽  
Long Distance ◽  
High Productivity ◽  
Merops Apiaster ◽  
One Year ◽  
Migratory Movements ◽  
The Relationship

AbstractUnderstanding the relationship between migratory performance and fitness is crucial for predicting population dynamics of migratory species. In this study, we used geolocators to explore migration performance (speed and duration of migratory movements, migratory timings) and its association with breeding phenology and productivity in an Afro-Palearctic insectivore, the European bee-eater (Merops apiaster), breeding in Iberian Peninsula. Bee-eaters migrated at higher travel speeds and had shorter travel duration in spring compared to autumn. Individuals that departed earlier or spent fewer days in-flight arrived earlier to the breeding areas. Our results show overall positive, but year-specific, linkages between arrival and laying dates. In one year, laying was earlier and productivity was higher, remaining constant throughout the season, while in the subsequent year productivity was lower and, importantly, declined with laying date. These results suggest that arriving earlier can be advantageous for bee-eaters, as in years when breeding conditions are favourable, early and late breeders produce high and similar number of fledglings, but when conditions are unfavourable only early breeders experience high productivity levels.

scholarly journals Manipulating individual state during migration provides evidence for carry-over effects modulated by environmental conditions

2011 ◽  
Vol 279 (1730) ◽  
pp. 876-883 ◽  
Author(s):  
Pierre Legagneux ◽  
Peter L. F. Fast ◽  
Gilles Gauthier ◽  
Joël Bêty
Keyword(s):  
Reproductive Success ◽  
Environmental Conditions ◽  
Experimental Studies ◽  
Residual Effects ◽  
Long Distance ◽  
Food Treatment ◽  
In Captivity ◽  
Breeding Grounds ◽  
Carry Over ◽  
Access To Food

Despite observational evidence of carry-over effects (COEs, events occurring in one season that produce residual effects on individuals the following seasons), to our knowledge no experimental studies have been carried out to explore how COEs might affect reproductive output. We simulated an environmental perturbation affecting spring-staging migrants to investigate COEs in greater snow geese ( Anser caerulescens atlanticus ). During three consecutive years, 2037 females captured during spring staging (approx. 3000 km south of their Arctic breeding grounds) were maintained in captivity (with or without access to food) for 0–4 days. Duration of captivity (but not food treatment) negatively affected reproductive success, probably through stress response. Reproductive success was reduced by 45–71% in 2 years, but not in a third year with unusually favourable breeding conditions. This unprecedented manipulation indicates that COEs can have a strong effect on individual reproductive success in long-distance migrants, but that this effect can be partly compensated for by good environmental conditions on the breeding ground.

Investigation on the control of multiphase flow behavior in a continuous casting tundish during ladle change

2020 ◽  
Vol 117 (6) ◽  
pp. 619
Author(s):  
Rui Xu ◽  
Haitao Ling ◽  
Haijun Wang ◽  
Lizhong Chang ◽  
Shengtao Qiu
Keyword(s):  
Multiphase Flow ◽  
Flow Behavior ◽  
Rolled Strip ◽  
Impact Zone ◽  
Steel Cleanliness ◽  
Carry Over ◽  
Slag Carry Over ◽  
Hot Rolled ◽  
Turbulence Inhibitor ◽  
The Impact

The transient multiphase flow behavior in a single-strand tundish during ladle change was studied using physical modeling. The water and silicon oil were employed to simulate the liquid steel and slag. The effect of the turbulence inhibitor on the slag entrainment and the steel exposure during ladle change were evaluated and discussed. The effect of the slag carry-over on the water-oil-air flow was also analyzed. For the original tundish, the top oil phase in the impact zone was continuously dragged into the tundish bath and opened during ladle change, forming an emulsification phenomenon. By decreasing the liquid velocities in the upper part of the impact zone, the turbulence inhibitor decreased considerably the amount of entrained slag and the steel exposure during ladle change, thereby eliminating the emulsification phenomenon. Furthermore, the use of the TI-2 effectively lowered the effect of the slag carry-over on the steel cleanliness by controlling the movement of slag droplets. The results from industrial trials indicated that the application of the TI-2 reduced considerably the number of linear inclusions caused by ladle change in hot-rolled strip coils.

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