高海拔和高纬度生境的相似性:综述以及青藏高原鸟类肾上腺皮质激素对应激反应的初步研究

在介绍性教科书、保护计划甚至基础著作中 ,常常将北极区和高山生物群系等同看待。高山和北极区生物群系无树的广阔区域 ,草本和非禾本科草本植物的初级生产力总量低 ,食物网单一。此外 ,除热带高山生境可能有例外 ,该两种环境都具有明显的季节性。但是 ,对于这些表面上相似的环境以前很少进行比较 ,而两者之间应具有明显的不同。我们假定 :如果环境相似 ,栖息在这些环境里的鸟类会对意外的应激刺激表现出相似的反应。相反 ,如果这些环境很不同 ,那么鸟类对剧烈应激的反应可进行调整以适应当地的不同环境 ,而不应一成不变。本文初步报道了青藏高原某些繁殖鸟类的肾上腺皮质反应 ,并与已发表的栖息于北极区苔原生态系统鸟类的数据进行了比较。白腰雪雀 (Onychostruthustaczanowskii)和棕颈雪雀 (Pyrgilaudaruficollis)被认为是高山代表物种 ,随着标准化捕捉 -处理 -抑制的应激刺激 ,它们表现出典型的血浆肾上腺皮质酮含量升高。但是 ,不同于许多北极区的代表物种 ,它们对应激的肾上腺皮质反应并无任何季节性变化。研究结果表示 :生活在高山和北极区环境下的鸟类物种可能具有激素反应以适应其生存环境所施加的生态挑战 [动物学报 49(1) :1～ 19,2 0 0 3]。     

冷暴露长爪沙鼠下丘脑-垂体-肾上腺轴对产热的调节

为探讨下丘脑 -垂体 -肾上腺轴在野生小哺乳动物产热中的调节作用 ,对正常及肾上腺去除的长爪沙鼠进行了冷暴露研究。正常雄性长爪沙鼠在急性冷暴露 ( 4± 1℃ ,1天 )条件下 ,下丘脑促肾上腺皮质激素释放激素的合成和释放没有显著变化 ,肾上腺皮质酮含量增加 4 5 8% ,差异显著 ,血清皮质酮水平有增加趋势 ;慢性冷暴露 ( 4± 1℃ ,3周 )后 ,肾上腺皮质酮含量增加到对照的 2 14倍 ,血清皮质酮含量维持较高水平。肾上腺去除的长爪沙鼠冷暴露 3周后 ,褐色脂肪组织 (BAT)产热 (细胞色素C氧化酶活力、线粒体GTP结合数量 )增加 ,下丘脑促甲状腺激素释放激素的合成和释放、血清三碘甲腺原氨酸水平以及血清去甲肾上腺素的浓度均有增加的趋势。表明冷暴露条件下长爪沙鼠肾上腺皮质酮的合成和释放增加 ,从而抑制BAT的产热 ,皮质酮对BAT产热的抑制部分是通过抑制下丘脑 -垂体 -甲状腺轴激素的合成和分泌以及抑制交感神经系统的活动而实现的。     

应激性高血压犬鼠脑干及下丘脑-垂体-肾上腺轴中肾上腺髓质素及其受体mRNA表达的改变

采用逆转录- 聚合酶链式反应检测了慢性足底电击结合噪声应激致高血压大鼠下丘脑、延髓、中脑、垂体和肾上腺等组织中编码肾上腺髓质素的肾上腺髓质素前肽原(preproadrenomedullin, ppADM) 基因以及ADM 的特异性受体组件降钙素受体样受体(calcitonin-receptor-like receptor,CRLR)和受体活性调节蛋白2 和3(receptor-activity-modifying proteins, RAMP2 和RAMP3)表达的变化。我们观察到:与对照组相比,以 3- 磷酸甘油醛脱氢酶作为内参照,15 d 足底电击结合噪声应激引起下丘脑、垂体和肾上腺中ppADM mRNA表达上调,而在延髓和中脑表达明显下调(P<0.01 或 P<0.05); CRLR基因表达量正常时在下丘脑相对较高,应激15 d 后CRLR 表达在延髓、中脑和下丘脑下调(P<0.01 或 P<0.05), 而在垂体和肾上腺的表达无明显变化;应激后RAMP2 基因在延髓和下丘脑表达上调,而在肾上腺表达显著下调(P <0.01), 其他部位无明显变化;RAMP3 基因在对照组大鼠的中脑和下丘脑表达较高,在应激性高血压大鼠的下丘脑和垂体表达上调(P<0.01 或P<0.05), 而在中脑和肾上腺表达下调(P<0.05), 在延髓中的表达变化无统计学差异。上述结果提示:慢性足底电击结合噪声应激引起明显的中枢和下丘脑- 垂体-肾上腺轴ADM 及其受体组件CRLR/RAMP2 或CRLR/R     

应激性高血压大鼠脑干及下丘脑-垂体-肾上腺轴中肾上腺髓质素及其受体mRNA表达的改变

采用逆转录-聚合酶链式反应检测了慢性足底电击结合噪声应激致高血压大鼠下丘脑、延髓、中脑、垂体和肾上腺等组织中编码肾上腺髓质素的肾上腺髓质素前肽原(preproadrenomedullin,ppADM)基因以及ADM的特异性受体组件降钙素受体样受体(calcitonin-receptor-like receptor,CRLR)和受体活性调节蛋白2和3(receptor-activty-modifying proteins,RAMP2和RAMP3)表达的变化.我们观察到:与对照组相比,以3-磷酸甘油醛脱氢酶作为内参照,15 d足底电击结合噪声应激引起下丘脑、垂体和肾上腺中ppADM mRNA表达上调,而在延髓和中脑表达明显下调(P＜0.01或P＜0.05);CRLR基因表达量正常时在下丘脑相对较高,应激15 d后CRLR表达在延髓、中脑和下丘脑下调(P＜0.01或P＜0.05),而在垂体和肾上腺的表达无明显变化;应激后RAMP2基因在延髓和下丘脑表达上调,而在肾上腺表达显著下调(P＜0.01),其他部位无明显变化;RAMP3基因在对照组大鼠的中脑和下丘脑表达较高,在应激性高血压大鼠的下丘脑和垂体表达上调(P＜0.01或P＜0.05),而在中脑和肾上腺表达下调(P＜0.05),在延髓中的表达变化无统计学差异.上述结果提示:慢性足底电击结合噪声应激引起明显的中枢和下丘脑-垂体-肾上腺轴ADM及其受体组件CRLR/RAMP2或CRLR/RAMP3基因的表达变化.但慢性应激后中枢源性ADM及其受体的表达变化对应激和血压的调节以及在应激致高血压中的确切作用及机制尚待进一步研究.     

追寻候鸟迁徙的漫漫长路

在一系列关于野生动物生活史和相关行为主题的纪录片中,法国导演雅克佩兰推出的记录片—《迁徙的鸟》,绝对是永恒中的经典。通过揭示鸟类生活史最为绚烂的周期—迂徙—的壮美,导演用最美的故事和场景打动了人心。观看影片的人们,随着鸟儿,完成了从南极到北极、从热带到苔原、从低地到喜马拉雅波澜壮阔的迁徙旅程。     

追寻候鸟迁徙的漫漫长路

在一系列关于野生动物生活史和相关行为主题的纪录片中,法国导演雅克佩兰推出的记录片—《迁徙的鸟》,绝对是永恒中的经典。通过揭示鸟类生活史最为绚烂的周期—迂徙—的壮美,导演用最美的故事和场景打动了人心。观看影片的人们,随着鸟儿,完成了从南极到北极、从热带到苔原、从低地到喜马拉雅波澜壮阔的迁徙旅程。     

全球气候变暖对武汉作为鸟类迁徙"中转站"地位的威胁

武汉市位于中国腹地,长江和汉水的交汇处,这里一直是南北候鸟迁徙的"中转站"之一,更是重要的候鸟越冬地和停歇地.由于地处南北过渡性气候,适合南、北候鸟常年生活,再加上"百湖之城"良好水资源条件和湿地环境更为鸟类的取食及营巢奠定了基础.正是因为这些气候及地理条件,所以有很多候鸟在此安家.然而,随着全球气温出现了整体上升的现象,这样的气候条件对鸟类的迁徙、繁殖是十分不利的.本文结合作者及其他学者对武汉鸟类调查的结果与近年武汉市气候状况的比对分析,发现武汉作为鸟类迁徙"中转站"的生态学地位发生了巨大变化,并讨论了全球气候变暖对武汉作为南北鸟类中转站生态地位的威胁状况,阐述了对全球环境保护的建议.     

野生鸟类应激反应的生理机制及其生态意义

应激反应是动物应对不利环境条件时的生理、内分泌及行为变化。该反应对动物的行为和生存力产生重要影响。突发的恶劣气候、被捕食、人类干扰等不利刺激可引起鸟类的突发应激。栖息地中长期缺乏食物、存在捕食者、季节变化以及社群中的社会性控制等生态因素可使鸟类发生慢性应激。突发应激是野生鸟类应对突发不利刺激的适应性反应,而慢性应激则可影响野生鸟类的免疫力、生殖力和体重,最终影响种群的存活力。本文综述了野生鸟类应激反应的生理机制及其生态意义,以期为我国的鸟类生态学研究提供借鉴。     

陕西红碱淖湿地鸥科鸟类组成及分布的研究

2005～2009年,采用路线调查法和定点观察法对陕西红碱淖湿地鸥科鸟类组成及其分布进行了调查研究.结果 表明:红碱淖分布有鸥科鸟类4属10种,在此繁殖的有5种,其中有全球性濒危鸟类--遗鸥的最大种群在此繁殖.记述了鸥科鸟类最早发现时间段、分布状况及迁徙数量情况,也探明了繁殖种群数量.并从植被类型、水位变化、食物因素、湖心岛生境状况和环境气候等因素分析了红碱淖鸥科鸟类迁徙状况、种群数量变化、繁殖情况等.     

俄罗斯远东地区勺嘴鹬繁殖地夏季水鸟调查

俄罗斯远东地区是全球鸟类重要的繁殖地之一,特别是楚科奇半岛的阿纳德尔地区是全球极危鸟种勺嘴鹬(Calidris pygmeus)已知的重要繁殖地。为了履行中俄候鸟及其栖息地保护双边协定,掌握俄罗斯远东的阿纳德尔地区夏季水鸟的资源状况,2017年6月25日至7月20日,中俄双方对阿纳德尔南部地区进行了夏季水鸟资源调查。调查区域主要包括阿纳德尔、从阿纳德尔至白令戈夫斯基的海域、白令戈夫斯基、梅内皮尔吉诺周边苔原区域以及附近海域四个部分。共记录35种水鸟,隶属于6目10科,其中14种有繁殖活动。分析中俄环志回收数据表明,在我国长江流域和东部沿海地区越冬的雁鸭类和鸻鹬类水鸟,夏季迁徙到俄罗斯的哈巴罗夫斯克、萨哈林岛、勘察加半岛、雅库特、楚科奇等远东地区繁殖。此外,勺嘴鹬的主要繁殖繁殖地梅内皮尔吉诺周边苔原地区存在着巢址被洪水淹没、卵和雏鸟遭天敌捕食等风险;在勺嘴鹬迁徙路线上的重要迁徙停歇地和越冬地的退化、环境污染和人为活动是导致勺嘴鹬种群数量下降的重要因素。研究结果表明,需要进一步加强中俄双方勺嘴鹬保护的合作与交流,共同保护鸟类的栖息地。     

Baseline and stress-induced levels of corticosterone during different life cycle substages in a shorebird on the high arctic breeding grounds

After a migratory flight of several thousand kilometers to their high arctic breeding grounds, red knots (Calidris canutus islandica, Scolopacidae) showed high baseline concentrations of plasma corticosterone (58 ng/mL). Such high baseline corticosterone levels may be conditional for the right behavioral and metabolic adjustments to environmental and social stresses that shorebirds experience on arrival in an unpredictable tundra breeding environment. Despite the high baseline levels of corticosterone, red knots still showed a marked stress response during the postarrival period, with corticosterone concentrations increasing significantly during a 60-min period of confinement. Baseline levels of corticosterone declined as the breeding season progressed. Red knots with brood patches, that is, birds that had completed egg laying and commenced incubation, had a reduced adrenocortical response to the stress of confinement compared with red knots with no, or with half-developed, brood patches. This is consistent with the idea that birds breeding in extreme environments with short breeding seasons may exhibit a decreased adrenocortical response to stressful events to prevent high corticosterone concentrations from inducing interruptions of reproductive behavior.     

Arctic spring: hormone-behavior interactions in a severe environment

Arctic breeding birds arrive on their nesting grounds in spring when weather conditions may still be extreme (low temperature, snow). The brief Arctic summer requires that they begin breeding as early as possible to take advantage of the ephemeral abundance of food to feed young. Failure to adjust to the local phenology results in drastically reduced reproductive success. Hormone-behavior adaptations may have evolved that maximize survival and reproductive success in the Arctic. It has been shown that the interrelationship of testosterone and territorial aggression, as birds arrive on the Arctic breeding grounds, varies according to species and locality. In some, territoriality is extremely brief following which birds become apparently refractory to the effects of testosterone. Others are territorial throughout the breeding season, but the dependence of these behaviors upon activation by testosterone is lost. Extensive data also indicate that Arctic birds modulate the adrenocortical response to acute stress. Secretion of corticosterone in response to a standardized capture stress protocol, used to mimic acute stress as a function of local environmental conditions, varies with the stage in the breeding cycle. Arctic breeding birds modulate the sensitivity of the adrenocortical response to acute stress at both the population and individual levels. These modulations are thought to be adaptations to allow the onset of territorial behavior and breeding in the face of potentially stressful conditions. Behavioral and physiological responses to corticosterone treatment are also diminished. A combination of these two hormone-behavior interrelationships can form important components of the proximate mechanisms by which birds, and other vertebrates, breed successfully in a severe and often capricious environment.     

The dilemma of where to nest: influence of spring snow cover,food proximity and predator abundance on reproductive success of an arctic-breeding migratory herbivore is dependent on nesting habitat choice

Pink-footed geese Anser brachyrhynchus nest in two contrasting but commonly found habitats: steep cliffs and open tundra slopes. In Svalbard, we compared nest densities and nesting success in these two environments over ten breeding seasons to assess the impact of spring snow cover, food availability to nesting adults and arctic fox Vulpes lagopus (main terrestrial predator) abundance. In years with extensive spring snow cover, fewer geese at both colonies attempted to breed, possibly because snow cover limited pre-nesting feeding opportunities, leaving adults in poor breeding condition. Nesting success at the steep cliff colony was lower with extensive spring snow cover; such conditions force birds to commit to repeated and prolonged recess periods at far distant feeding areas, leaving nests open to predation. By contrast, nesting success at the open tundra slope was not affected by spring snow cover; even if birds were apparently in poor condition they could feed immediately adjacent to their nests and defend them from predators. Foxes were the main nest predator in the open tundra slopes but avian predators likely had a larger impact at the steep cliffs colony. Thus, the relative inaccessibility of the cliffs habitat may bring protection from foxes but also deprives geese from readily accessing feeding areas, with the best prospects for successful nesting in low spring snow cover years. Our findings indicate that spring snow cover, predator abundance and food proximity did not uniformly influence nesting success of this herbivore, and their effects were dependent on nesting habitat choice.     

Modulation of the hypothalamic-pituitary-adrenal axis of an Arctic-breeding polygynandrous songbird,the Smith's longspur,Calcarius pictus

To successfully reproduce in the Arctic, birds must modulate their neuroendocrine and behavioural systems. These adjustments include an attenuation of the stress responsiveness of the hypothalamic-pituitary-adrenal (HPA) axis to external stimuli and a behavioural insensitivity to high corticosterone (B) levels. The HPA axis was examined in free-living territorial polygynandrous Smith's longspurs (Calcarius pictus) that migrate to breed on the Arctic tundra. Basal and stress-induced B levels were measured through the breeding season and were found to be significantly lower in females compared with males. This was not a consequence of adrenal insensitivity, because intrajugular injections of adrenocorticotrophin hormone (ACTH) enhanced B release in incubating females. In males the adrenocortical response to stress was significantly attenuated during the parental phase compared with arrival at the breeding ground. In contrast to temperate passerines, there was no significant decrease in male territorial aggressive behaviour when B was experimentally elevated, suggesting a behavioural insensitivity to glucocorticoids. This mechanism is hypothesized to increase reproductive success by preventing interruptions to parental care during transient deleterious environmental perturbations, which are often experienced in the short Arctic breeding season. Modulation of the HPA axis in this species in relation to life-history stage, lifetime reproductive success and the polygynandrous mating system is discussed.     

Deepened snow increases late thaw biogeochemical pulses in mesic low arctic tundra

Pulses of plant-available nutrients to the soil solution are expected to occur during the dynamic winter–spring transition in arctic tundra. Our aims were to quantify the magnitude of these potential nutrient pulses, to understand the sensitivity of these pulses to winter conditions, and to characterize and integrate the environmental and biogeochemical dynamics of this period. To test the hypotheses that snow depth, temperature and soil water—and not snow nutrient content—are important controls on winter and spring biogeochemistry, we sampled soil from under ambient and deepened snow every 3 days from late winter to spring, in addition to the snowpack at the start of thaw. Soil and microbial biogeochemical dynamics were divided into distinct phases that correlated with steps in soil temperature and soil water. Soil solution and microbial pools of C, N and P fluctuated with strong peaks and declines throughout the thaw, especially under deepened snow. Snowpack nutrient accumulation was negligible relative to these biogeochemical peaks. All nutrient and microbial peaks declined simultaneously at the end of snowmelt and so this decline was delayed by 15 days under deepened snow. The timing of these nutrient pulses is critical for plant species nutrient availability and landscape nutrient budgets. This detailed and statistically-based characterisation of the winter–spring transition in terms of environmental and biogeochemical variables should provide a useful foundation for future biogeochemical process-based studies of thaw, and indicate that spring thaw and possibly growing season biogeochemical dynamics are sensitive to present and future variability in winter snow depth.     

Extreme spring conditions in the Arctic delay spring phenology of long-distance migratory songbirds

Arctic regions are warming rapidly, with extreme weather events increasing in frequency, duration, and intensity just as in other regions. Many studies have focused on how shifting seasonality in environmental conditions affects vegetation phenology, while far fewer have examined how the breeding phenology of arctic fauna responds. We studied two species of long-distance migratory songbirds, Lapland longspurs, Calcarius lapponicus, and white-crowned sparrows, Zonotrichia leucophrys gambelii, across five consecutive breeding seasons in northern Alaskan tundra. We aimed to understand how spring environmental conditions affected breeding cycle phenology, including the timing of arrival on breeding grounds, territory establishment, and clutch initiation. Spring temperatures, precipitation, and snow-free dates differed significantly among years, with 2013 characterized by unusually late snow cover. In response, we found a significant delay in breeding-cycle phenology for both study species in 2013 relative to other study years: the first bird observed was delayed by 6–10 days, with mean arrival by 3–6 days, territory establishment by 6–13 days, and clutch initiation by 4–10 days. Further, snow cover, temperature, and precipitation during the territory establishment period were important predictors of clutch initiation dates for both species. These findings suggest that Arctic-breeding passerine communities may have the flexibility required to adjust breeding phenology in response to the increasingly extreme and unpredictable environmental conditions—although future generations may encounter conditions that exceed their current range of phenological flexibility.     

Recolonization following past persecution questions the importance of persistent snow cover as a range limiting factor for wolverines

Globally, climate is changing rapidly, which causes shifts in many species' distributions, stressing the need to understand their response to changing environmental conditions to inform conservation and management. Northern latitudes are expected to experience strongest changes in climate, with milder winters and decreasing snow cover. The wolverine (Gulo gulo) is a circumpolar, threatened carnivore distributed in northern tundra, boreal, and subboreal habitats. Previous studies have suggested that wolverine distribution and reproduction are constrained by a strong association with persistent spring snow cover. We assess this hypothesis by relating spatial distribution of 1589 reproductive events, a fitness-related proxy for female reproduction and survival, to snow cover over two decades. Wolverine distribution has increased and number of reproductive events increased 20 times in areas lacking spring snow cover during our study period, despite low monitoring effort where snow is sparse. Thus, the relationship between reproductive events and persistent spring snow cover weakened during this period. These findings show that wolverine reproductive success and hence distribution are less dependent on spring snow cover than expected. This has important implications for projections of future habitat availability, and thus distribution, of this threatened species. Our study also illustrates how past persecution, or other factors, that have restricted species distribution to remote areas can mask actual effects of environmental parameters, whose importance reveals when populations expand beyond previously restricted ranges. Overwhelming evidence shows that climate change is affecting many species and ecological processes, but forecasting potential consequences on a given species requires longitudinal data to revisit hypotheses and reassess the direction and magnitude of climate effects with new data. This is especially important for conservation-oriented management of species inhabiting dynamic systems where environmental factors and human activities interact, a common scenario for many species in different ecosystems around the globe.     

Local snow melt and temperature—but not regional sea ice—explain variation in spring phenology in coastal Arctic tundra

The Arctic is undergoing dramatic environmental change with rapidly rising surface temperatures, accelerating sea ice decline and changing snow regimes, all of which influence tundra plant phenology. Despite these changes, no globally consistent direction of trends in spring phenology has been reported across the Arctic. While spring has advanced at some sites, spring has delayed or not changed at other sites, highlighting substantial unexplained variation. Here, we test the relative importance of local temperatures, local snow melt date and regional spring drop in sea ice extent as controls of variation in spring phenology across different sites and species. Trends in long‐term time series of spring leaf‐out and flowering (average span: 18 years) were highly variable for the 14 tundra species monitored at our four study sites on the Arctic coasts of Alaska, Canada and Greenland, ranging from advances of 10.06 days per decade to delays of 1.67 days per decade. Spring temperatures and the day of spring drop in sea ice extent advanced at all sites (average 1°C per decade and 21 days per decade, respectively), but only those sites with advances in snow melt (average 5 days advance per decade) also had advancing phenology. Variation in spring plant phenology was best explained by snow melt date (mean effect: 0.45 days advance in phenology per day advance snow melt) and, to a lesser extent, by mean spring temperature (mean effect: 2.39 days advance in phenology per °C). In contrast to previous studies examining sea ice and phenology at different spatial scales, regional spring drop in sea ice extent did not predict spring phenology for any species or site in our analysis. Our findings highlight that tundra vegetation responses to global change are more complex than a direct response to warming and emphasize the importance of snow melt as a local driver of tundra spring phenology.     

Coping mechanisms of alpine and arctic breeding birds: extreme weather and limitations to reproductive resilience

As ground nesting homeotherms, alpine and arctic birds mustmeet similar physiological requirements for breeding as otherbirds, but must do so in more extreme conditions. Annual springsnowfall and timing of snow melt can vary by up to 1 month anddaily temperatures near the ground surface vary from below freezingto over 45°C in alpine and arctic habitats. Species breedingin these environments have various behavioral, physiological,and morphological adaptations to cope with energetically demandingconditions. We review the ways birds cope with harsh and variableweather, and present data from long term field studies of ptarmiganto examine effects of spring weather on reproduction. In variablebut normal spring conditions, timing of breeding was not influencedby snow melt, snow depth or daily temperatures in the alpine,as breeding did not commence until conditions were generallyfavorable. Arctic ptarmigan tended to vary breeding onset inresponse to spring conditions. Generally, birds breeding inalpine and arctic habitats suffer a seasonal reproductive disadvantagecompared to birds at lower latitudes or elevations because thebreeding window is short and in late years, nest failure maybe high with little opportunity for renesting. Coping mechanismsmay only be effective below a threshold of climactic extremes.Despite strong resilience in fecundity parameters, when snowmeltis extremely delayed breeding success is greatly reduced. Alpineand arctic birds will be further challenged as they attemptto cope with anticipated increases in the frequency and severityof weather events (climate variability), as well as generalclimate warming.     

Does short-term fasting lead to stressed-out parents? A study of incubation commitment and the hormonal stress responses and recoveries in snow petrels

The hormonal stress response is flexible and can be modulated by individuals according to its costs and benefits. Therefore, it is predicted that parents in poor body condition should modify their hormonal stress response, and thus, redirect energy allocation processes from parental care to self-maintenance when stressors occur. To test this prediction, most studies on free-living vertebrates have only focused on the stress response while the stress recovery – how quickly hormonal levels return to baseline values – has been neglected. Moreover, most studies have only focused on corticosterone – the primary mediator of allostasis – without paying attention to prolactin despite its major role in mediating parental behaviors. Here, we examined the effect of a short-term fasting event on the corticosterone and prolactin stress responses and recoveries, and we subsequently explored their relationships with parental decision in the snow petrel (Pagodroma nivea). By comparing the hormonal profiles of fasting and non-fasting snow petrels, we showed that parents modulate their corticosterone (but not prolactin) stress response according to their energetic status. We also described for the first time the hormonal stress recoveries in wild birds and found that they did not differ between fasting and non-fasting birds. Importantly, egg neglect was negatively correlated with circulating prolactin but not corticosterone levels in this species, demonstrating therefore a complex link between body condition, parental behavior and circulating corticosterone and prolactin levels. We suggest that both corticosterone and prolactin play a major role in the way parents adjust to stressors. This multiple signaling may allow parents to fine-tune their response to stressors, and especially, to activate specific allostasis-related mechanisms in a timely manner.