Chick Size Research Articles

Organic farming reduces pesticide load in a bird of prey

Human activities have led to the contamination of all environmental compartments worldwide, including bird species. In birds, both the environment and maternal transfer lead to high inter-brood variability in contamination levels of pollutants, whereas intra-brood variability is generally low. However, most existing studies focused on heavy metals or persistent compounds and none, to our knowledge, addressed the variability in contamination levels of multiple pesticides and the factors influencing it. In this study, the number of pesticides detected (of 104 compounds searched) and the sum of their concentrations in the blood of 55 Montagu's harrier (Circus pygargus) nestlings from 22 nests sampled in 2021 were used as metrics of contamination levels. We investigated the effect of organic farming at the size of male's home range (i.e., 14 km2) and chicks' sex and hatching order on contamination levels. We did not find a difference between inter-brood and intra-brood variability in pesticide contamination levels, suggesting a different exposure of siblings through food items. While chicks' sex or rank did not affect their contamination level, we found that the percentage of organic farming around the nests significantly decreased the number of pesticides detected, although it did not decrease the total concentrations. This finding highlights the potential role of organic farming in reducing the exposure of birds to a pesticide cocktail.

The landscape of fear in cattle farms? How the presence of barn swallow influences the activity of pest flies

Abstract Insectivorous birds are key suppliers of crucial ecosystem services, especially important for pest control in agricultural systems, and are globally decreasing at a fast rate. Among them, the declining barn swallow Hirundo rustica is particularly linked to cattle farms, where it is impacted by changes in livestock husbandry practices. The presence of swallows in cattle sheds might contribute to control insect pests, but such an effect had never been explored. With this work, we evaluated the potential control effect exerted by barn swallow on economically relevant pest insects, filth flies. To assess whether swallows inside the cattle sheds influence the activity rate of pest flies (especially Musca domestica and Stomoxys calcitrans), we assessed the relative abundance of swallows and flies over 16 weeks in nine different cattle farms in Non valley (Trentino, North‐east Italy), either occupied or not by nesting swallows. From April 2022 to August 2022, we collected weekly data on the activity rate of flies by placing eight white spot cards inside each of nine cattle sheds and counting the deposition of faecal and regurgitation spots by flies. Simultaneously, we collected weekly data regarding swallow occurrence, brood size, number and age of chicks. We applied generalised linear mixed effect models on the activity rate of flies, with spot card and farm as nested random effects, to account for potential random variability between cards and farms. We then assessed through model selection the effect of number of cows, number of swallows, and temperature or week alternatively. Temperature and week were modelled also in interaction with the number of swallows. Fly activity rate followed a seasonal trend with a peak in July, which was markedly lower where swallows were present. Moreover, the positive relationship between flies and temperature was lessened when swallows were abundant. Synthesis and applications. Barn swallows are effective biological control agents for lowering pest fly activity in livestock farms. Farmers were actively involved in swallow conservation within their sheds, also with a shared memorandum‐of‐intent. Harnessing the ecosystem services supplied by farmland birds could bring positive outcomes for people and biodiversity.

From maternal glucocorticoid and thyroid hormones to epigenetic regulation of offspring gene expression: An experimental study in a wild bird species.

Offspring phenotype at birth is determined by its genotype and the prenatal environment including exposure to maternal hormones. Variation in both maternal glucocorticoids and thyroid hormones can affect offspring phenotype, but the underlying molecular mechanisms, especially those contributing to long-lasting effects, remain unclear. Epigenetic changes (such as DNA methylation) have been postulated as mediators of long-lasting effects of early-life environment. In this study, we determined the effects of elevated prenatal glucocorticoid and thyroid hormones on handling stress response (breath rate) as well as DNA methylation and gene expression of glucocorticoid receptor (GR) and thyroid hormone receptor (THR) in great tits (Parus major). Eggs were injected before incubation onset with corticosterone (the main avian glucocorticoid) and/or thyroid hormones (thyroxine and triiodothyronine) to simulate variation in maternal hormone deposition. Breath rate during handling and gene expression of GR and THR were evaluated 14 days after hatching. Methylation status of GR and THR genes was analyzed from the longitudinal blood cells sampled 7 and 14 days after hatching, as well as the following autumn. Elevated prenatal corticosterone level significantly increased the breath rate during handling, indicating an enhanced metabolic stress response. Prenatal corticosterone manipulation had CpG-site-specific effects on DNA methylation at the GR putative promoter region, while it did not significantly affect GR gene expression. GR expression was negatively associated with earlier hatching date and chick size. THR methylation or expression did not exhibit any significant relationship with the hormonal treatments or the examined covariates, suggesting that TH signaling may be more robust due to its crucial role in development. This study provides some support to the hypothesis suggesting that maternal corticosterone may influence offspring metabolic stress response via epigenetic alterations, yet their possible adaptive role in optimizing offspring phenotype to the prevailing conditions, context-dependency, and the underlying molecular interplay needs further research.

INFORMATION ON THE BIOLOGY OF PICA PICA BACTRIANA

Abstract The article shows the relevance of the topic, the distribution of Pica pica bactriana, meeting characteristics and its study, the duration of the research and the methods used in the work, the number of nests found, nesting places, meeting places and their number, singing, mating. behavioral responses to breeding, number and location of nests, nesting interspecific relationships, nesting duration and use, nest shape, dimensions, nest location, nest construction, nest components and morphometric dimensions, oviposition and duration and brood care during incubation, changes in the egg, hatching, chick size, growth and development, images of reproduction, relation to the nest of the new generation Its biological characteristics and importance, such as its habitat, information about its nighttime, relationship with historical monuments, nutrition and food types, have been studied

Long-term observation of the egg and chick size in the nests of Larus ichthyaetus in Lake Chany, Russia

This data set describes the long-term observation and morphological study of the eggs of the great black-headed gull Larus ichthyaetus in the gull nesting colonies on the islands of Lake Chany. Lake Chany is located in the Baraba forest-steppe of the West Siberian Plain, Russia, between the Ob and Irtish rivers. Lake Chany is protected by the Ramsar Convention on the Wetlands of International Importance, indicating that the lake is an important site for migratory birds, including L. ichthyaetus. This dataset contains the size and fate of all eggs, as well as the size of hatched chicks in 1164 observed L. ichthyaetus nests from 1993 to 2003.

Dynamics of Poultry Production System, Constraints, Opportunities and Marketing in Ethiopia

The objectives this paper focuses on thedynamic ofpoultry production system constraints, opportunities and marketing system in the Ethiopia in the form of summary from past, recent and/or current studies. Currently, Ethiopia poultry production systems are classified into industrial and integrated/medium- and large-scale intensive systems and family poultry production systems (i.e. the small-scale intensive is characterized specialized, commercial day-old chicks (DOCs) or pullets (200–1 000 broilers, 100–500 layers), commercial balanced rations and good quality houses. semi-intensive is characterized by flocks ranging from 50 to 200 birds, using commercial, crossbred or indigenous breeds reared under scavenging management conditions with regular supplementation., extensive scavenging is characterized ranging from 5 to 50 birds comprised of indigenous and/or crossbred chickens and it is practiced by households having access to rural markets and small-extensive scavenging systemsit is based on a flock size of 1–5 indigenous chickens kept under scavenging conditions.The national average flock size of chicks, cockerels, pullet, hen, cocks, and total chicken per households were 5.3, 1.3, 1.7, 4, 1.5 and 11.1, respectively in Ethiopia. All scavenging chicken producer practice supplementary feeding (100%) from all type of feed, supplemented maize account (63%). It needs incorporate protein source feed at dry season. Keywords: Production system, Ethiopia, chicken, productivity DOI: 10.7176/JMCR/77-01 Publication date: March 31 st 2021

Incubation, hatchery practice and the welfare of layer hens

For modern layers to achieve optimum production performance and welfare state, the entire production process needs to be managed to achieve target bodyweight, body composition and flock uniformity. In addition to genetic improvements, flock health, environment, nutrition and on-farm husbandry practices, incubation and hatchery practices have become a focal point for producing optimum chick quality. Chick quality is a collective term involving chick size and anatomical features, physiology, robustness and liveability over the first week after placement. Chick quality is a key focus for hatcheries as this has been positively correlated with overall flock performance, especially egg production, shell quality, liveability and animal welfare. Recent advances in incubation have focussed on the benefits of all-in–all-out (single-stage) machines. Innovation in incubation systems is completely conducted today by international manufacturers, and is largely driven by the meat chicken industry. Disposal of male layer chicks has increased as a consumer welfare concern, and while investment in research and legislation changes are focussed towards providing or driving new solutions, there are currently no commercial options for industry to deal with this problem before incubation or hatch. Chick transport systems and equipment have also significantly improved in recent years, providing optimum conditions to ensure temperature uniformity and minimal moisture loss during transit before placement, thus optimising chick quality. Together, recent improvements in incubation equipment and hatchery practice can produce commercial layer chicks that are healthy, of high quality, and are then in an optimal physiological state and condition to achieve their genetic potential.

Parasitism by an invasive nest fly reduces future reproduction in Galápagos mockingbirds.

Organisms allocate limited resources to competing activities such as reproduction, growth, and defense against parasites and predators. The introduction of a novel parasite may create new life history trade-offs. As hosts increase their investment in self-maintenance or defense, the cost of parasitism may carry over to other aspects of host biology. Here, in an experimental field study, we document delayed effects of an introduced nest parasite, Philornis downsi, on reproduction of Galápagos mockingbirds (Mimus parvulus). Parasitism of first nests reduced both the number and size of chicks that parents hatched when they re-nested several weeks later. The delayed effect of P. downsi on future reproduction may have been mediated by behavioral shifts by the parents to avoid or resist parasitism. Our results demonstrate that effects of parasitism can persist even after immediate exposure ends. We draw attention to the potential implications that introduced parasites have for host reproductive strategies.

Extreme offspring ornamentation in American coots is favored by selection within families, not benefits to conspecific brood parasites

Offspring ornamentation typically occurs in taxa with parental care, suggesting that selection arising from social interactions between parents and offspring may underlie signal evolution. American coot babies are among the most ornamented offspring found in nature, sporting vividly orange-red natal plumage, a bright red beak, and other red parts around the face and pate. Previous plumage manipulation experiments showed that ornamented plumage is favored by strong parental choice for chicks with more extreme ornamentation but left unresolved the question as to why parents show the preference. Here we explore natural patterns of variation in coot chick plumage color, both within and between families, to understand the context of parental preference and to determine whose fitness interests are served by the ornamentation. Conspecific brood parasitism is common in coots and brood parasitic chicks could manipulate hosts by tapping into parental choice for ornamented chicks. However, counter to expectation, parasitic chicks were duller (less red) than nonparasitic chicks. This pattern is explained by color variation within families: Chick coloration increases with position in the egg-laying order, but parasitic eggs are usually the first eggs a female lays. Maternal effects influence chick coloration, but coot females do not use this mechanism to benefit the chicks they lay as parasites. However, within families, chick coloration predicts whether chicks become "favorites" when parents begin control over food distribution, implicating a role for the chick ornamentation in the parental life-history strategy, perhaps as a reliable signal of a chick's size or age.

Body size and first-winter survival of Red-crowned Crane Grus japonensis chicks

ABSTRACTAn analysis of the biometrics of 187 individually marked Red-crowned Crane Grus japonensis chicks from Japan revealed that larger chicks were more likely to seen alive in their first-winter. Male chicks were larger than females but sex did not influence apparent survival, nor did brood size determine body size.

Factors affecting the reproductive performance of barbary partridges in cereal croplands of Northwestern Morocco: the role of timing of breeding and vegetation cover at fine-scale

In Morocco, the barbary partridge (Alectoris barbara) is the major game species, highly valued by the nation’s hunters. Until recently little was known about factors affecting reproductive parameters of this species on cereal croplands in North Africa. In 2018, 51 nests were found and analyzed across two agricultural areas of Northwestrn Morocco (AGR1 and AGR2). In this work, I assessed the relevance of a set of environmental and anthropogenic variables in predicting the clutch size and number of chicks hatched per nest, by means of generalised linear mixed models (GLMM). The average clutch size and hatching success per nest were 12.26 (± 0.57) and 9.26 (± 0.95), respectively. In the two sites, clutch-size increased as the date advanced, but was significantly larger in AGR1 (13.17 ± 0.84, n = 26) than in AGR2 (11.20 ± 0.70, n = 25). The number of chicks hatched per nest increased over time but also with the increase of the vegetation cover at fine-scale. Barbary partridge reproductive parameters were neither affected by landscape nor anthropogenic variables. I discuss these findings and their ecological, and future research implications. I recommended to pursuit the investigations, while considering imperatively the age/sex ratios and predation pressure.

Nest survival data confirm managed housing is an important component to the conservation of the eastern purple martin

ABSTRACTThe purple martin (Progne subis) is entrenched in a consistent, long‐term decline. This is especially true for the subspecies east of the Rocky Mountains (P. s. subis), which today nests almost exclusively in provisioned housing (birdhouses and hollow gourds) provided by citizen scientists. One benefit of provisioned housing is reduced nest‐site competition with nonnative European starlings (Sturnus vulgaris) and house sparrows (Passer domesticus) when managed by citizen scientists. Increased competition for nest sites and subsequently lower productivity due to declining management of available housing is speculated to be primary factors for their long‐term declines. To assess whether managed housing promoted high nest‐survival metrics, we used a 19‐year database (1995–2013) of nest‐check records provided by Project MartinWatch, a citizen science program of the Purple Martin Conservation Association. We compared nest ecology metrics and survival among housing and entrance‐hole type to assess if specific provisioned housing or entrance‐hole type increased clutch size or number of chicks fledged. Using 72,627 nests across 8 regions monitored by citizen scientists, our major findings were 1) nest survival was >85% among 8 regions in the eastern United States and Canada; and 2) clutch size and number of fledglings produced were slightly larger in natural and artificial gourds with entrances designed to exclude European starlings; but 3) housing and entrance‐hole types were not important predictors of nest survival and clutch size had a small, inverse relationship with daily nest survival (βClutch = −0.002). Our results suggest managed housing is an important conservation tool based on previously undocumented high nest survival across the numerous artificial housing options. Our findings encourage the use of artificial and natural gourds with European starling‐resistant entrance holes, but promotion of managed artificial housing of any type in North America is beneficial and strongly encouraged. © 2019 The Wildlife Society.

Is there a context-dependent advantage of extra-pair mating in Tree Swallows?

ABSTRACT The “good-genes” hypothesis to explain female extra-pair mating states that females benefit from this behavior by acquiring better genes for their offspring. Despite extensive research, results are mixed, and the predictions of the good-genes hypothesis have been met in fewer than half of published papers. One possible explanation for this lack of consensus is that the benefits of extra-pair copulation are context-dependent. Here we use chick size, the probability of fledging, and telomeres, the protective caps of chromosomes, as markers for individual quality. Telomere length (TelL) integrates across many stressors and covaries with probability of survival and reproductive success. To test whether benefits to extra-pair (EP) matings are context-dependent we look at the telomere length of extra-pair and within-pair offspring (EPO and WPO, respectively) reared either in experimentally enlarged broods or in broods left at their natural size. We predicted that EPO would have longer telomeres than WP...

The effect of dietary energy and protein levels on body weight, size, and microflora of ostrich chicks

The aim of this study was to evaluate the effect of different dietary energy and protein supplements on performance, weekly body sizes or body frame size, and microbiota of ostrich chicks during 2–9 weeks of age. Two metabolic energy levels of 2400 and 2600 kcal/kg live weight and three protein levels of 20, 22, and 24% were used. A total of 36 ostrich chickens (Struthio camelus) of the blue and black African breed were used. Body weight, 12 body measurements (i.e., circumference of the head, neck, breast, abdomen, thigh, body height, length of tail, list the other 5 here) and excretion of microbial population (Escherichia coli, Coliforms bacteria, and Lactobacillus bacteria) were measured. Mean body weight in each week of the experiment was generally the lowest when chicks were offered 2600 kcal/kg dietary energy and 24% protein. Of the 12 body measurements, the breast, abdomen, and thigh circumference and also body length were greater at the lower energy (2400 kcal/kg) and higher protein (24%) levels. Total Aerobic bacteria excretion was generally lower in response to the diet containing the higher level of energy. We conclude that ostrich chickens during 2–9 weeks of age can grow on diets that contain lower energy levels.

Fortune telling seabirds: sooty shearwaters (Puffinus griseus) predict shifts in Pacific climate

Indices calculated from “muttonbirding” diaries collected by the Rakiura Māori of New Zealand were correlated with future values of the Southern Oscillation Index (SOI), and the Pacific Decadal Oscillation (PDO) from 1957 to 2010. Spearman correlations showed that La Nina events tended to occur after those harvest seasons with relatively high success and chick size, whereas El Nino events tended to occur after harvest seasons with relatively low success and chick size. Generalized boosted regression models show that chick size alone is able to predict shifts in SOI from 0 to 12 months after the harvest. A model that included chick size, 2-year average PDO (prior to the harvest), and one year averages of SOI (prior to the harvest), was able to predict shifts in SOI 13–20 months after the harvest. It is likely that sooty shearwater adults (and therefore chick size and quantity) are being affected by oceanographic conditions that are also precursors to shifts in SOI, and that there is a complex interaction between PDO prior to the harvest, the harvest indices and SOI. The location and timing of adult birds at the time they are provisioning chicks could lead to potential mechanisms and requires further study.

Effects of flock age, prestorage heating of eggs, egg position during storage and storage duration on hatchability parameters in layer parent stock

This study was carried out to determine the effect of different preincubation storage periods, different prestorage egg treatments and different egg positions during storage on egg weight loss, embryo mortality, hatchability, hatchling weight and chick sex ratio at hatch in layer parent stock. The following factors were analyzed: flock age (24 weeks, 65 weeks), prestorage heating periods (0, 5 hours at 37.8 °C), storage periods (0, 3, 6, 9, 12, 15 days at 15.0 °C) and egg positions (pointed end up, pointed end down). Parent stock age had a significant (p < 0.05) effect on chick weight. This increase in chick size due to advancing age of layer parent stock is attributable to the fact that egg weight significantly (p < 0.05) improved as the age of parent stock increased. Significant differences were found in absolute egg weight loss during the storage period, as a function of flock’s age (p < 0.05). Eggs stored with the small end down lost less weight during storage compared with the eggs stored with the small end up. Hatchability of fertile eggs did significantly decline after storage for 9, 12, and 15 days. Flock age, prestorage heating and egg position during storage had no positive or detrimental effect on hatchability of set and fertile eggs and to male:female ratio under the conditions of this study. A flock age x egg position interaction indicated that females, hatched from eggs derived from old flock exhibited a tendency to be heavier when eggs are stored pointed end down whereas the egg position did not affect the female weight when eggs came from young flock.

Compensating for a stressful start: maternal corticosterone, offspring survival, and size at fledging in the Zebra Finch, Taeniopygia guttata

All organisms are exposed to a variety of physical, environmental and psychological challenges throughout their lives. We administered repeated oral doses of the stress hormone corticosterone (CORT) to ovulating Zebra Finches (Taeniopygia guttata) in order to mimic a disruptive environment, and investigated the effect on their reproductive output as well as outcomes for their offspring. Although females treated with CORT produced larger clutches than control females, hatching success was significantly reduced in the CORT-treated group, though there was no evidence of bias in offspring sex-ratio. Both treatment and sex had an effect on the size of chicks at hatching and their growth rate. Chicks from the experimental group were smaller at hatching than control chicks but grew faster. Similarly, male chicks were smaller than female chicks at hatching but grew faster than females. However, there was no significant difference in overall condition at nutritional independence, indicating that increased growth rates resulted from compensatory growth. These results have broad evolutionary implications, as maternal CORT is capable of affecting viability of eggs and offspring phenotype, even when maternal diet and body condition remain unchanged. As such, glucocorticoids may play a role in regulating population productivity and offspring phenotype, which provides a promising area for further research into the effects of maternal stress on adult offspring in successive generations.

Estimating Regions of Oceanographic Importance for Seabirds Using A-Spatial Data.

Advances in GPS tracking technologies have allowed for rapid assessment of important oceanographic regions for seabirds. This allows us to understand seabird distributions, and the characteristics which determine the success of populations. In many cases, quality GPS tracking data may not be available; however, long term population monitoring data may exist. In this study, a method to infer important oceanographic regions for seabirds will be presented using breeding sooty shearwaters as a case study. This method combines a popular machine learning algorithm (generalized boosted regression modeling), geographic information systems, long-term ecological data and open access oceanographic datasets. Time series of chick size and harvest index data derived from a long term dataset of Maori ‘muttonbirder’ diaries were obtained and used as response variables in a gridded spatial model. It was found that areas of the sub-Antarctic water region best capture the variation in the chick size data. Oceanographic features including wind speed and charnock (a derived variable representing ocean surface roughness) came out as top predictor variables in these models. Previously collected GPS data demonstrates that these regions are used as “flyways” by sooty shearwaters during the breeding season. It is therefore likely that wind speeds in these flyways affect the ability of sooty shearwaters to provision for their chicks due to changes in flight dynamics. This approach was designed to utilize machine learning methodology but can also be implemented with other statistical algorithms. Furthermore, these methods can be applied to any long term time series of population data to identify important regions for a species of interest.

Experimental reduction of haematocrit affects reproductive performance in European starlings

Summary Given the function of haemoglobin and observed increases in haematocrit during periods of increased energetic demands, haematocrit and haemoglobin are assumed to be related to aerobic capacity. Reductions in haematocrit and haemoglobin during reproduction are similar in magnitude to increases associated with aerobically demanding activities, and therefore, we sought to investigate whether these reductions in haematology have consequences for reproductive performance. We analysed associations between natural variation in haematology in free‐living European starlings (Sturnus vulgaris) and reproductive performance. To test whether transient reductions in haematology during different stages of reproduction (egg production and late incubation/early chick rearing) affected measures of reproductive performance, we also manipulated haematology using phenylhydrazine (PHZ), which lyses red blood cells. To investigate effects of reductions of haematology during egg‐laying, we treated females with PHZ or saline (control) upon completion of their unmanipulated first clutch and removed eggs to induce the production and rearing of a replacement clutch. To investigate effects of reductions of haematology during chick rearing, we treated females during incubation of the unmanipulated first clutch and then monitored the subsequent hatching and rearing of the clutch. Individuals with higher haematocrit and haemoglobin initiated nesting earlier. Furthermore, higher haemoglobin levels during incubation were associated with a greater number of chicks fledged. PHZ treatment prior to egg production resulted in a significant delay in the laying of replacement clutches, but had no effect on provisioning rate or the size or number of chicks fledged. PHZ treatment during incubation and early chick rearing resulted in decreased hatchling mass in all years and a decrease in the size and number of fledglings in one of 2 years. The year that the effect of PHZ was observed appeared to be a particularly difficult year, as hatchling mass, brood size at hatching and at fledging were low among control females compared to other years. Our results suggest that a reduction in haematology during reproduction can be functionally significant, but that these costs are context‐dependent.

Factors driving Adélie penguin chick size, mass and condition at colonies of different sizes in the Southern Ross Sea

Body size, mass and condition can affect an organism's ability to cope with variation in resource availability or metabolic demand, particularly as juveniles reach independence. It follows that changes to parental provisioning efficiency (size and frequency of meals) through intraspecific competition or environmental conditions that affect prey availability may affect chick size, mass and condition and ultimately post-fledging survival. We examined how Adelie penguin chick size, mass and condition varied among colonies of different sizes on Ross Island during a 15 yr period of high environmental variability and varying intraspecific competition. Aiding the study was a natural experiment in which the presence of 2 giant icebergs midway through the study abnormally increased sea ice concentration (SIC), altering adults' access to food. Concur- rently, the colonies were rapidly increasing in size; based on previous work, this indicated increased trophic competition near colonies, a trend likely indicating a changing food web in the greater region. Results showed that increased amounts of sea ice, which reduced the ability of adults to access food, had a negative effect on the size and mass of chicks. However, a greater pro- portion of fish (vs. krill) in the diet had a positive effect on chick size. Moreover, in some cases, increased intraspecific competition may be a more important driver of provisioning rate and chick size than abiotic factors, with chicks showing the effects of reduced food delivery at larger colonies. Understanding these patterns will allow better understanding of how factors such as climate change and altered food webs may affect Adelie penguin populations.