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The objective of this study was to evaluate the intake, performance, and economic viability of crossbred Holstein calves (n = 16) fed diets containg different levels of baru meal (Dipteryx alata . Vog) as a replacement for corn (0, 25, 50, and 72%). Total solid feed, concentrate, and forage intake, nutrient intake, weight gain, ingestive behavior, and economic viability were evaluated. Total solid feed and concentrate intake linearly increased (p<0.05) with the replacement of corn by baru meal, however, weight gain (13.7 Kg) was not affected (p>0.05). Baru meal inclusion linearly increased the intake of crude protein, minerals, ether extract, and non-fibrous carbohydrates. Concentrate feeding time exhibited a quadratic effect, with a maximum of 75.92 min. day-1 at 67% replacement. Economic analysis showed that the 50% replacement diet result in higher feed costs but lower cost per kilogram of gain. The inclusion of baru meal up to 72% of corn replacement increased intake without compromising the performance during preweaning phase. A 50% replacement provided the best economic return.

The present study was carried out to enumerate induced breeding technique and larval development of Macrognathus pancalus (Hamilton, 1822) reared under captivity. Five different doses of Ovasis hormone (T1, T2, T3, T4, and T5) with 3 replicas each were administered to the matured brooders to standardize the breeding performance of the target species. The results indicated variation in fertilization rate, latency period, egg output and hatching rate in response to different treatments. Spawning was occurred between 20-24 hrs of injection in all the experiments at 26.33±0.88°C water temperature. Among all the experimental trials, the highest fertilization rate was observed in T3 (96.15±0.60) of E2 and the highest hatching rate was observed in T3 (92.49±1.00) of E2. The present work elucidated the viability of seed production of M. pancalus reared under confined condition which will useful for aquaculture and conservation.

Animals' performance of basic functional behaviours, such as foraging and movement, may improve with age as a result of past experiences. In migratory birds, for example, due to earlier or more efficient migration, older and likely more experienced individuals tend to arrive at breeding sites earlier and enjoy better breeding conditions than younger conspecifics, resulting in a higher reproductive success. Yet, despite the advantages of early arrival for breeding adults, the long‐term effects of fledging early and/or with a higher body condition on chicks' future fitness prospects remain largely unexplored. In differential migration systems, low‐quality or socially subordinate individuals may be constrained to sub‐optimal migratory behaviours associated with lower demographic rates. Therefore, producing high‐quality chicks may enhance the survival of offspring. In this study, we analysed data from the long‐term ringing programme on the breeding population of Eurasian spoonbills in the Camargue (southern France) to investigate how breeder age may influence the timing of breeding and, in turn, how this may affect chick body condition and their subsequent migratory behaviour. Using breeding resightings of birds individually marked as a chick since 2008, combined with chick biometric measurements and subsequent winter resightings of offspring, we show that older spoonbills tend to breed earlier in the season than younger individuals, and that early breeders, regardless of age, are more likely to produce chicks with higher body condition than late breeders. Finally, migratory behaviour of juveniles appears to be influenced by the timing of breeding, with later‐born juveniles tending to undertake less demanding migrations (without crossing major ecological barriers) than juveniles born earlier in the breeding season. Our study therefore highlights the relevance of long‐term studies to better understand the complex breeding phenology of migratory species, which can lead to changes in population‐level patterns and processes.

Inter-individual differences in demographic traits of iteroparous species can arise through learning and maturation, as well as from permanent differences in individual ‘quality’ and sex-specific constraints. As the ability to acquire energy determines the resources an individual can allocate to reproduction and self-maintenance, foraging behavior is a key trait to study to better understand the mechanisms underlying these differences. So far, most seabird studies have focused on the effect of maturation and learning processes on foraging performance, while only a few have included measures of individual quality. Here, we investigated the effects of age, breeding experience, sex, and individual breeding quality on the foraging behavior and location of 83 known-age Adélie penguins at Cape Bird, Ross Sea, Antarctica. Over a 2 yr period, we showed that (1) high-quality birds dived deeper than lower quality ones, apparently catching a higher number of prey per dive and targeting different foraging locations; (2) females performed longer foraging trips and a higher number of dives compared to males; (3) there were no significant agerelated differences in foraging behavior; and (4) breeding experience had a weak influence on foraging behavior. We suggest that high-quality individuals have higher physiological ability, enabling them to dive deeper and forage more effectively. Further inquiry should focus on determining the physiological differences among penguins of different quality.

ABSTRACT Increased parental relatedness occurs in small wild populations and in closed colonies in captivity and reduces offspring fitness. A closed colony of Peromyscus maniculatus is maintained as genetically diverse stock at the Peromyscus Genetic Stock Center since 1963. Breeding records are available for all the years of breeding in captivity, which allows evaluation of the breeding performance since the inception of the stock. Kinship calculations showed that increased parental relatedness results in offspring loss, which is consistent with the operation of inbreeding depression and is common in small populations, both wild and captive. Nonetheless, an adaptive response was recorded that mitigated the adverse consequences of inbreeding and contributed to the long‐term stability of the colony: When parental relatedness increased, more offspring were produced, resulting in the overall number of viable offspring being unaffected. The underlying mechanism involved adjustments in the interval for mating between related parents, causing the production of more litters. These adaptive changes indicate that the harmful consequences of inbreeding may be partially relieved by mechanisms involving changes in the animals' reproductive strategy. The availability of the breeding records of P. maniculatus enables the performance of additional studies asking different questions regarding the breeding dynamics of a closed colony under regulated conditions. Analysis of the breeding records of Peromyscus maniculatus in captivity indicated the operation of inbreeding depression that triggered an adaptive response according to which when parental relatedness increased, more offspring are produced. The underlying mechanism involved adjustments in the interval for mating between related parents causing the production of more litters. These adaptive changes indicate that the harmful consequences of inbreeding may be partially relieved by mechanisms involving changes in the animals' reproductive strategy.

[...]obtaining sufficient numbers of fry and fingerlings from natural waters for stocking ponds is a challenge. [...]the species is experiencing population declines in its native ranges. The propagation of this particular species has the potential to generate additional revenue streams for hatchery operators and ornamental fish traders. [...]it could also lead to the creation of employment opportunities for individuals residing in rural areas, specifically through the management of and cultivation of this species in nurseries. Prior research on X. cancila breeding biology is essential for efficient fisheries management and breeding programs. [...]the purpose of this study was to improve hormone-induced breeding methods for X. cancila and create management strategies for fry nurseries. At four hours intervals, physicochemical water parameters including dissolved oxygen (mg l -1), water temperature (C), pH, and total dissolved solids (TDS) were measured in spawning tanks of every treatment and also in the pond in which the larvae were reared Experimental design We chose CPG, HCG, and Ovaprim for the breeding program for X. cancila in Bangladesh due to their widespread availability, cost-effectiveness, and popularity among hatchery owners.

We used a long-term data set (26 years) from Audouin's Gull ( Larus audouinii ), a long-lived seabird, to address the relationship between the age-dependent pattern of reproductive performance and environmental conditions during breeding. Although theoretical models predict that the youngest and oldest breeders (due to inexperience and senescence, respectively) will perform less well than intermediate age classes, few empirical data exist regarding how this expected pattern varies with food availability. To assess the influence of age and food availability (corrected by population size of the main consumers to take into account density dependence) on a number of breeding parameters (laying dates, egg volume, clutch size, and hatching success), we modeled mean and variances of these parameters by incorporating heterogeneity into generalized linear models. All parameters varied with age and to different degrees, depending on food availability. As expected, performance improved with increased food supply, and the observed age pattern was quadratic, with poorer breeding performances occurring in extreme ages. For most parameters (except for laying dates, for which age and food did not interact), the pattern changed with food somewhat unexpectedly; the differences in performance between age classes were higher (i.e., the quadratic pattern was more noticeable) when food was more readily available than when food availability was lower. We suggest that, under poor environmental conditions, only high-quality individuals of the younger and older birds bred and that the differences in breeding performance between age classes were smaller. Although variances for egg volume were constant, variances for laying dates were highest for the youngest breeders and tended to decrease with age, either due to the selection of higher-quality individuals or to a greater frequency of birds skipping breeding with age, especially when food was in low supply. Our results show that mean and variances of breeding parameters changed with age, but that this pattern was different for each parameter and also varied according to food availability. It is likely that, other than food, certain additional factors (e.g., sex, cohort effects, density dependence) also influence changes in breeding performance with age, and this may preclude the finding of a common pattern among traits and among studies on different taxa.

In recent decades, the breeding populations of the yellow-legged gull Larus michahellis (YLG) have increased significantly, primarily due to the increase in open refuse dumps and discards from fisheries. Portugal’s largest YLG breeding colony is located on Berlenga Island, where population numbers have been monitored since 1974. The population grew exponentially until 1994, prompting the implementation of population control measures, including culling adult birds and eggs. A long-term data base including number of breeding birds (since 1974), breeding parameters (since 2002), and trophic niches (using stable isotopes since 2011) of YLG breeding on Berlenga was related with oceanographic parameters, fish landings and quantity of urban waste. Trophic ecology showed strong relationships with oceanographic parameters (wNAO, Chl-a, and SST) and fisheries landings (the 10 most frequently consumed species by the YLG, traded at fish auctions in the main fishing harbour nearby). The results indicated significant relationships between reproductive performance and fisheries landings, particularly with demersal species that gulls primarily access through fisheries discards. However, population control measures played a pivotal role in stabilising and even reducing the population, despite sporadic events of poor oceanographic productivity in the past decade having a consistent impact on the reduction in breeding individuals.

Migration is energetically costly, and many passerines prepare for and maintain migration with hyperphagia and increased fuel or fat reserves. During spring migration, as they approach their breeding grounds, passerines may deposit fat in excess of what is needed to complete migration. Individuals may carry excess fuel reserves as insurance against potentially poor environmental conditions in early spring (insurance hypothesis). If this is true, individuals arriving early at northern stopover locations or their breeding grounds should have greater energy reserves than later arrivals. Alternatively, passerines may arrive in spring with excess fat to help offset the demands of breeding (breeding performance hypothesis). Given the energetic requirements of egg production, females may arrive with greater reserves than males if excess fat directly or indirectly offsets breeding costs. We analyzed the energetic condition of 12 warbler species mist-netted during migration from 1999 to 2012 at Braddock Bay Bird Observatory, Monroe County, New York, USA. This northern stopover location is near the breeding range (in relation to total migratory distance) for most of the parulid species we examined and, therefore, is a likely location to show carryover effects between migration and breeding. In 11 of the 12 species, energetic condition was greater in the spring than in the fall for both sexes; and in all 12 species, condition was greater in females than in males in both seasons. Contrary to the insurance hypothesis, condition increased with arrival date for most species during spring migration. Although better condition in females supports the breeding performance hypothesis, the presence of this difference in both seasons suggests that additional factors influence energetic condition in parulids. Given that males arrive in better condition in the spring than when they depart in the fall, individuals of both sexes may carry excess energy reserves during spring migration to potentially use for reproductive efforts.

Considered extinct as breeding species in the early 2000s, the Saker Falcon was recovered when the first active nest from the new history of the species in Bulgaria was discovered in 2018, formed of two birds that were re-introduced back in 2015. Currently, there is only one confirmed wild breeding pair in the country - the male from 2015 with a female changed in 2020, released again as a part of the programme, in 2016. This is a report on the preliminary results and analysis of the ongoing establishment phase of the re-introduction of the Saker Falcon ( Falco cherrug ) in Bulgaria - first ever performed for this species in the country and globally. The period studied is 2015-2020. Following the re-introduction activities started in 2011, the current phase is defined by standardised methodology and a unified approach. Analysed and presented are methods for captive breeding and hacking, the breeding performance of the falcons, the number of released individuals, data from the post-fledging dependence period and a model of population growth.