Fitness can be profoundly influenced by the age at first reproduction (AFR), but to date the AFR-fitness relationship only has been investigated intraspecifically. Here we investigated the relationship between AFR and average lifetime reproductive success (LRS) across 34 bird species. We assessed differences in the deviation of the Optimal AFR (i.e., the species-specific AFR associated with the highest LRS) from the age at sexual maturity, considering potential effects of life-history as well as social and ecological factors. Most individuals adopted the species-specific Optimal AFR and both the mean and Optimal AFR of species correlated positively with lifespan. Interspecific deviations of the Optimal AFR were associated with indices reflecting a change in LRS or survival as a function of AFR: a delayed AFR was beneficial in species where early AFR was associated with a decrease in subsequent survival or reproductive output. Overall, our results suggest that a delayed onset of reproduction beyond maturity is an optimal strategy explained by a long lifespan and costs of early reproduction. By providing the first empirical confirmations of key predictions of life-history theory across species, this study contributes to a better understanding of life-history evolution.
Helping to rear the offspring of others may be a way for younger birds to gain access to future reproduction especially when turnover of breeding opportunities is low. However, this explanation is not applicable to cases where adults also help, or when roles shift between helpers and breeders. Over a period of 6‐yr, we studied a marked population of azure‐winged Magpie (Cyanopica cyanus) breeding in a non‐territorial, colonial system. Magpies bred in a highly flexible cooperative system, in which individuals helped at different stages of the breeding cycle, including nest building, feeding the incubating female and feeding the young and removing the faecal sacs. On average, 50% of hatched nests were assisted by helpers‐at‐the‐nest, and nest success appeared to be positively related to the presence of helpers. Helpers were predominantly males. Although juveniles were more likely to help, both juvenile and adult birds helped. Individual birds behaved as helpers either as a first‐option or after having attempted their own breeding (second‐option helpers). An individual helper may assist more than one nest during the same breeding season and in different breeding seasons. Reversals between breeder and helper roles were common in both directions, within a breeding season and between years. Helping behaviour is an option for almost any member of the colony. Therefore, hypotheses related to the enhancement of future breeding opportunities for juveniles can be discarded as general explanation of helping in this species. Although the decision to help appeared to be influenced by proximal environmental conditions hindering successful breeding, the associated benefits of helping as opposed to simply recovering for future reproduction, especially for former breeders, deserve further study.
For cooperatively breeding birds, it has been proposed that breeders should reduce their investment in eggs when they count on helpers, because this can be compensated for by helpers provisioning of nestlings. Data from some species have supported this prediction, but this is not the case in others. It has also been proposed that mothers should not reduce but rather increase investment if the presence of helpers enhances the reproductive value of offspring, a pattern that might also influence egg production as long as helpers are predictable for laying females. Here, we studied maternal expenditure in eggs and clutches in the Iberian magpie, to see whether mothers reduce their expenditure at the egg stage in the presence of helpers. Our results show that investment in clutches varied depending on the year, date in the season and age of the mother, but there were no reductions in maternal expenditure per individual egg when they counted on helpers. On the contrary, a pattern emerged in the opposite direction of more investment in eggs associated with the future presence of helpers at the nestling stage. Our data suggest that the predictability of helpers, along with the type of benefits accrued from the contribution of helpers, may be crucial to understanding the reaction of mothers at egg production.
Like all corvids, the Azure-winged Magpie Cyanopica cyanus is sexually monomorphic in plumage, making it difficult to distinguish between males and females in the field. We examined sexual size dimorphism in a population of Iberian Azure-winged Magpies C.c. cooki and used a discriminant function analysis based on five morphological characters to determine the sex of first-year and adult individuals. Females were significantly smaller than males for all tested variables within each age class except for keel length of first-year individuals. In both sexes, wing length of adults was greater than that of yearlings, but only males showed significant differences in tail length between age classes (longer in first-year birds). Stepwise discriminant analysis indicated that tail length and head plus bill length were the most accurate variables in a discriminant function model, predicting the sex of yearlings with about 90% accuracy. Adding wing length to the model yielded the same level of accuracy for adults. We propose a simple system to sex Iberian Azure-winged Magpies, using only two or three variables easily measured in the field, which provides classification with a high level of accuracy.
Introduction The global prevalence of diabetes in 2019 in adults was estimated to be 9.3%. This study developed in Ecuador, for the first time, instruments to assess patient‐reported outcomes and experiences. Methods The Experiences of the Person with Diabetes (EPD) Questionnaire is a diabetes‐specific instrument. A mixed‐methods study was conducted. First, a qualitative item development phase that included four focus groups and six semi‐structured interviews with patients was conducted in different rural and urban areas of Ecuador to obtain information on culture, beliefs, demographics, diet and social perspectives. A second quantitative phase for psychometric validation was carried out in primary care settings of rural and urban areas of Ecuador. Results Forty‐two and four hundred and eighty‐nine participants were included in each phase, respectively. The item development phase resulted in a questionnaire of 44 items (23 for perceived outcomes and 21 for experiences). In the validation study, most participants were women (58%) and from urban areas (57%). Exploratory factor analysis revealed three dimensions for each instrument. Outcomes instrument dimensions were symptoms and burnout, worries and fears and social limitations. Experiences instrument dimensions were information, patient‐centred care and care delivery. Cronbach's α values of the total score and dimensions were high, ranging between .81 and .93 in both instruments. Confirmatory factor analysis showed an acceptable fit of the data. Conclusion The EPD Questionnaire is probably the first instrument developed to assess patient‐reported experiences and perceived outcomes in a middle‐income country that included patients to capture all dimensions relevant for the intended population. Its psychometric properties are robust and could provide valuable information for clinicians and policymakers in the region. Patient or Public Contribution The development of these instruments has taken into consideration patients and the public since their conception. A qualitative approach gathered relevant information related to the cultural, social and economic burden of different populations in Ecuador. Before validation, a pilot test was carried out with users of the National Health Services to obtain their perspectives and insights of the developed instrument. Finally, during the data analysis, we have given special consideration to social variables such as rural and urban populations.
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