Winter Food Research Articles

Native and non-native winter foraging resources do not explain Pteropus alecto winter roost occupancy in Queensland, Australia

Anthropogenic land use change concurrent with introductions of non-native species alters the abundance and distribution of foraging resources for wildlife. This is particularly concerning when resource bottlenecks for wildlife are linked to spillover of infectious diseases to humans. Hendra virus is a bat-borne pathogen in eastern Australia. Spillovers align with winter food shortages for flying foxes and flying foxes foraging in agriculture or peri-urban lands, as opposed to native forests. It is believed the increased abundance and spatiotemporal reliability of non-native species planted in anthropogenically modified areas compared to native, ephemeral diet species may be a key draw for flying foxes into urban and peri-urban areas. We investigate the explanatory power of environmental factors on the winter roost occupancy of the reservoir for Hendra virus, the black flying fox Pteropus alecto, from 2007-2020 in Queensland, Australia. We measured the extent, spatial aggregation, and annual reliability of typical (i.e. native) and atypical (i.e. non-native) winter habitat species in 20km foraging areas around roosts surveyed by the National Flying Fox Monitoring Program. We find that neither the extent nor the spatial distribution of winter habitats explained black flying fox winter roost presence. Although the establishment of roosts was associated with high reliability for typical winter diet species, the reliability of frequently listed winter diet species surrounding surveyed roosts was not different between roosts that were occupied versus unoccupied in the winter. Significant interactions between lagged weather conditions and winter habitats identified by the best model did not reflect observable differences in patterns of occupancy upon scrutiny. Static measures of winter habitat and weather conditions poorly explained the winter roost occupancy of black flying foxes. Understanding the drivers of flying fox movement and presence requires further investigation before they can be thoughtfully integrated into Hendra spillover prevention efforts and flying fox management.

Токсичные и биогенные элементы в органах и тканях белой куропатки (Lagopus lagopus L., 1758) на севере Красноярского края (обзор)

Studying the concentration of biogenic and toxic microelements in the body tissues of wild animals is relevant for organizing regional environmental monitoring, assessing the state of populations and ensuring the safety of meat and wild products. The studies were carried out to determine the content of biogenic and toxic elements in the organs and tissues of the willow ptarmigan in the north of the Krasnoyarsk Region, Russia, where different levels of technogenic pollution are expected. The iron, copper, nickel, lead, and cadmium content in the pectoral muscles and liver of willow ptarmigan (Lagopus lagopus L.) (n=162), bagged during five hunting seasons in 2005–2019, were determined using atomic absorption spectrometry. The levels of lead, cadmium and iron in the tissues were significantly higher in contaminated areas, while the copper levels did not differ. Element concentrations in liver and skeletal muscle in impact areas were highly correlated with each other. This may be related to common sources of pollutant emissions. Sex differences in micronutrient content can be determined by spatial differentiation of the sexes during migration, seasonal feeding patterns, and the specific birds’ metabolism in reproductive period. Cadmium and lead content in liver and muscle tissue samples from impact areas exceeded current food hygiene standards, which may pose a threat to consumers. Probably, high levels of lead and cadmium reflect the increased content of metals in food items primarily willow sprouts and buds, which are the most important winter food for ptarmigan.

Survey of Fungal Diseases on Barley, Wheat, and Oats at Tillering to Stem Extension Stages in Southern Regions of Korea during 2020-2021

Cereal, including barley, wheat, and oats, is a major winter food crop in Korea. Despite recent changes in agricultural environments in response to climate change, fungal diseases that could affect cereal productivity remain poorly understood. In this study, we investigated the incidence of diseases in barley, wheat, and oats in the southern part of Korea. We collected fungal pathogens from seven locations where cereals were grown. In March-April of 2020 and 2021, a total of 92 fungal isolates were collected, mainly from the stem base or leaves of cereal crops during the tillering and stem extension stages of cereals in Korea. The collected isolates were identified based on morphological and molecular biological characteristics. The dominant species was <i>Ceratobasidium cereale</i> (42.4%), followed by <i>Pyrenophora teres</i> (21.7%), <i>P. avenae</i> (10.9%), <i>Alternaria alternata</i> (6.5%), and <i>Epicoccum tobaicum</i> (6.5%). In addition, <i>P. tritici-repentis</i> (3.3%), <i>Cladosporium</i> sp. (3.3%), <i>Fusarium</i> sp. (3.3%), and <i>Nigrospora</i> sp. (2.2%) were also collected as minority groups. Our results will provide information on fungal pathogens that occur during the growing season of cereals in Korea, particularly during the tillering and stem extension stages. In addition, the isolates collected from this study can serve as a valuable resource for conducting simulations on climate change, focusing on temperature and humidity.

The Individual Division of Food Hoarding in Autumn Brandt's Voles (Lasiopodomys brandtii).

Brandt's voles (Lasiopodomys brandtii), one of the main non-hibernating rodent species in the typical grassland of Inner Mongolia, live in groups and have the behavioral habit of hoarding food in underground warehouses in autumn to prepare for the winter food shortage ahead. The division of labor and cooperation are typical behavior patterns of gregarious mammals, but it is unclear whether Brandt's voles exercise a division of labor in food hoarding before overwintering. To explore the division of food hoarding in Brandt's voles during the autumn period, three treatments, namely added food, added food + competition, and control, were set up with three replicates. An infrared camera was positioned to observe and record the behavior of Brandt's voles under different treatments. Next, behavioral experiments regarding food-hoarding division were performed on individuals. The results showed that (1) Brandt's voles had two types of hoarding behavior, namely high food hoarding and low food hoarding, but not all individuals displayed hoarding behavior. (2) In all treatments, feeding behavior, which was the most important type of behavior, accounted for the highest proportion of all behaviors. (3) There was no significant difference in body weight and sex between high- and low-food-hoarding individuals of Brandt's voles, and there was no significant difference between high- and low-food-hoarding individuals in other divisions of labor either. (4) There was no significant difference in inquiry ability between high- and low-food-hoarding groups, but there was a significant difference in spatial memory. High-food-hoarding individuals had greater spatial memory. In summary, Brandt's voles had two types of hoarding behavior: high food hoarding and low food hoarding. Furthermore, high-food-hoarding individuals had greater spatial memory.

A Preliminary Evaluation of Faba Bean as a Green Shell Bean in Virginia, USA

Even though faba bean (Vicia faba L.) is an important food crop on worldwide basis, its use as a vegetable i.e. use of green seeds as food is limited. We were interested in characterizing production and food quality traits of faba bean grown in eastern USA. Our main objective is to develop faba bean as a winter alternative crop for this region to diversify cropping system that currently mainly depends upon cereal grain crops. This necessitates existence of winter-hardy faba bean varieties. We conducted a preliminary experiment with two winter-hardy faba bean breeding lines to record production and seed composition traits. Two faba bean lines (VSX-BL and VSX-BH) were planted in the field in November 2022 and green pods were harvested in June 2023 at physiological maturity. Values of most of the traits under study were statistically similar between the two lines except for concentration of phosphorus. Results demonstrated that faba bean green pod and green seeds yields could be approximately 5700 and 2100 kg ha-1. The shelling percent in green faba bean pods was approximately 37 whereas seed number per pod was approximately 2.6. Concentrations (g 100 g-1) of fructose, glucose, and sucrose were 0.245, 0.668, 2.9021, respectively whereas concentrations of Fe and Zn (mg kg-1) were 103.7 and 69.7, respectively. Green faba bean seeds contained small amounts of RFO carbohydrates. Seed composition traits of green faba bean seeds compare well with green seeds of pea, soybean, and white lupin. Our results provide a positive proof of concept that production of green faba bean as an alternate winter food legume crop in eastern USA is possible.

Winter field survey of bird feeders in two Hungarian cities

Abstract Bird feeding by people is one of the most popular human-wildlife interactions globally. Urban ecology studies generally recognize that cities offer a more favourable habitat for many wintering birds compared to natural areas, primarily due to the increased availability of the winter food sources provided by people. However, actual field surveys about the residents’ bird feeding activity are rare. Here we surveyed bird feeders during the winter of 2021–2022 at 5-5 locations in two cities in Hungary. We recorded the number and type of bird feeders, the type of food offered, the number of bird species and individuals visiting the feeders. The density of feeders was higher in Veszprém, a middle-sized city (range: 60.1–206.1 bird feeders/km2) compared to Budapest, the capital city of Hungary (23.3–83.0 bird feeders/km2). The most frequent food types were fat balls, seed mix, and sunflower seeds in both cities. We registered a total of 516 individuals of 24 species on the feeders, and found that the type of the feeder, but not the city, significantly affected both the number of individuals and species visiting bird feeders. These results help to get a more complete picture of how the winter food supplies of birds are shaped by urbanization.

Facultative migration in two thrush species (Fieldfare and Redwing): Rowanberry abundance is more important than winter weather

Facultative migration is thought to be influenced by food and weather, with birds remaining in northern areas if food is abundant and weather conditions are benign, but migrating south when food is scarce and weather is harsh. However, the relative importance of these two factors has rarely been tested with long-term data, and effects of weather are poorly documented. Here, I assess whether winter numbers of the Fieldfare (Turdus pilaris) and the Redwing (T. iliacus) in southern Norway during the period 1980–2020 varied in relation to the abundance of an important source of winter food (rowanberries, Sorbus aucuparia) and indices of winter harshness (North Atlantic Oscillation index, temperature, duration of snow cover). Two regions with contrasting winter harshness (western Norway with a maritime climate, eastern Norway with a continental climate) were compared. Winter numbers of Fieldfare in both regions, and Redwing in eastern Norway, were highest in years with high rowanberry abundance. Weather had mixed influence on thrush winter numbers, but interacted with rowanberry abundance in several cases so that small numbers of thrushes occurred with the combination of low rowanberry abundance and harsh weather. Such interactions occurred both in eastern and western Norway, and for both species, including for the Redwing in western Norway. In conclusion, facultative migration was strongly related to food availability with large numbers wintering in years with large rowanberry crops, and with additional effects of harsh weather working in concert with low rowanberry abundance to reduce wintering numbers to low levels in some years.

Spatial behaviors and seasonal habitat use of the increasingly endangered thick-billed parrot (Rhynchopsitta pachyrhyncha)

The thick-billed parrot (Rhynchopsitta pachyrhyncha) inhabits highland pine forests in the Sierra Madre Occidental ranges of northwestern Mexico. Their populations have declined significantly to < 2000 individuals due to habitat loss, illegal hunting and increasing predation. Despite their ecological and cultural importance and increasingly endangered status, the species is data deficient. Our study aimed to inform and enhance conservation management strategies for thick-billed parrots with information on their spatial ecology, habitat use, migratory behaviors and social associations. We deployed biotelemetry devices to conduct the first tracking study of wild thick-billed parrots. Our study revealed that thick-billed parrots are seasonal migrators, departing their breeding habitats around October and returning from southern habitats around April. Our research also identified previously unknown overwintering sites and migratory stopover locations, as well as a new nesting site. The parrots exhibited high spatial variability in range shifting behavior, but all tracked parrots exhibited range shifts during migration, with durations of 3–181 days and distances of 173–765 km. They traveled in close social groups and migratory routes primarily followed high-elevation forests along the Sierra Madre Occidental ranges. Home range analysis indicated smaller breeding site ranges and larger overwintering ranges, possibly reflecting nesting constraints and winter food resource dispersion. Parrot spatial associations favored high-elevation forest landscapes with tall and wide-trunked trees, underscoring the importance of preserving old-growth forests for nesting and foraging. Less than 20% of parrot habitats have formal regulatory protections. Conservation management efforts must focus on increasing protections for nesting areas, overwintering habitats, and key migratory stopover sites. As climate change exacerbates regional threats, integrated management plans involving local stakeholders and communities are essential for the parrots' long-term survival and the preservation of their old-growth forest habitats.

Delineating the spatial drivers of agri-environment scheme adoption at field and farm levels

Agri-environment schemes (AES), introduced by the EU Common Agricultural Policy (CAP), aim to compensate land owners for implementing environmentally-friendly practices. Whilst literature has examined their effectiveness and how farmer characteristics govern AES adoption, there is a lack of knowledge about the spatial drivers of AES, particularly structural, biophysical and landscape factors in the UK. Using the Humber region as a case study, this paper explores how the uptake of Countryside Stewardship options has varied from 2016 to 2021. It also examines 2500 farms from the field- and farm-level data of 2019 to better understand what type of land British farmers are adopting AES on. Logistic regression analysis is used to identify the factors (including farm and landscape characteristics, designated sites and land quality) that best explain overall AES adoption, as well as specific scheme adoption, at the field- and farm-level. Our analysis reveals that ‘buffer strips’, ‘hedgerow management’, ‘permanent grassland’, and ‘winter bird food’ are the most commonly adopted schemes of 2019. AES are generally adopted on larger fields and farms that feature marginalised, unproductive and vulnerable land, except for ‘buffer strips’ which showed a larger tendency to appear on fields with more profitable, higher quality land. This study, therefore, supports the notion that AES are generally placed on lower quality land and that large proportions of agricultural land owners are not effectively targeted. With the expected loss of direct payments to farmers in the UK as a result of the Department for Environment, Food & Rural Affairs (DEFRA) post-Brexit re-evaluation of rural policy, these results call for the Sustainable Farming Incentive (SFI) to be made more accessible and inclusive to a broader diversity of farmers.

Quelites Pasados of the Sierra Tarahumara, Chihuahua, Mexico: An Interdisciplinary Ethnobotanical Study of Leafy Green Vegetables

Leafy green vegetables have been a part of human diets throughout human history. Globally, they are gaining recognition since these wild foods could play an important role in food security. Quelites (the Mexican term for these resources) are dehydrated to produce “quelites pasados” by the Rarámuri in anticipation of the scarcity of food in winter. The diversity of quelites in the state of Chihuahua includes species of the widely consumed Amaranthus, as well as endemic, native, and introduced species that are eaten locally. The present work generated nutritional, sensory, and molecular information on four species that are consumed in the Sierra Tarahumara: Amaranthus palmeri, Amaranthus powellii, Arracacia edulis, and Phacelia platycarpa. Their nutritional analysis exhibited high protein values and a significant concentration of macro- and micronutrients. The acceptance by the public of the species of Amaranthus was high, while that of Arracacia edulis and Phacelia platycarpa was lower. Because of the morphological similarity within the two pairs of quelites, their DNA barcodes were generated as an identification tool which, together with the nutritional and sensory results, provides added value to the four “quelites pasados” of the Sierra Tarahumara. This study could be considered a starting point for sustainable use of native vegetables in future economic programs of regional agrobiodiversity, and even replicated globally.

Foraging Routine of Two Common Urban Birds on Berries of Exotic Livistona chinensis: A Winter Supplement in an Urban Landscape

Chinese Fan Palm, Livistona chinensis, was introduced as an ornamental plant towards the end of the nineteenth century in Pakistan, and since then, it has been used as a popular plant in urban landscaping. It dominates the green belt of parks, recreational gardens and road verges in Lahore, Pakistan. Recent trends in the plantation of fast-growing palm species and other exotics have replaced L. chinensis in urban landscaping. In this study, observations made on the daily routine of foraging of L. chinensis berries by two common urban birds, the red vented bulbul (Pycnonotus cafer) and the house crow (Corvus brachyrhynchos), showed that their consumption of berries peaked in December and January, but the duration of foraging was shown to be longer in house crows as compared to red vented bulbuls. This period of consumption corresponds to the time when the pulp of the berries has become soft, and during this period, no other fruits are available in the urban landscape. Nutrient analysis showed that the pulp of the ripened berries is a rich source of nutrients, and these berries are providing an ideal winter food to counter the increased energetic demands experienced by urban birds during the coldest part of the year, thus helping birds avoid the risk of starvation. This dietary intake of berries by birds also provides a rationale to popularize L. chinensis as an essential component of the planting palette of the urban landscape. This research can be considered as starting point for broad public support to improving landscape planning for managing nature in cities.

Isotopic Overlap of Invasive and Native Consumers in the Food Web of Lake Trasimeno (Central Italy).

An advanced characterization of the trophic niche of non-indigenous species (NIS) may provide useful information on their ecological impact on invaded communities. Here, we used carbon and nitrogen stable isotopes to estimate pairwise niche overlaps between non-indigenous and native consumers in the winter food web of Lake Trasimeno (central Italy). Overall, a relatively low pairwise overlap of isotopic niches was observed between NIS and native species. The only exception was the Louisiana crayfish Procambarus clarkii, which showed a relatively high and diffuse overlap with other native invertebrates. Our findings highlighted a high niche divergence between non-indigenous and native species in Lake Trasimeno, suggesting a potentially low degree of interspecific competition that may facilitate coexistence and, in turn, limit the strength of impacts. The divergent results obtained for the Louisiana crayfish indicate that additional control measures for this invasive species are needed to mitigate its impact on the Lake Trasimeno system.

Single-Cell Atlas Reveals the Hemocyte Subpopulations and Stress Responses in Asian Giant Softshell Turtle during Hibernation.

Hibernation in turtle species is an adaptive survival strategy to colder winter conditions or food restrictions. However, the mechanisms underlying seasonal adaptions remain unclear. In the present study, we collected hemocytes from Pelochelys cantorii and compared the molecular signature of these cells between the active state and hibernation period based on single-cell RNA sequencing (scRNA-seq) analysis. We found six cell types and identified a list of new marker genes for each cell subpopulation. Moreover, several heat shock genes, including the Hsp40 family chaperone gene (DNAJ) and HSP temperature-responsive genes (HSPs), were upregulated during the hibernation period, which predicted these genes may play crucial roles in the stress response during hibernation. Additionally, compared to hemocytes in the active state, several upregulated differentially expressed immune-related genes, such as stat1, traf3, and socs6, were identified in hemocytes during the hibernation period, thus indicating the important immune function of hemocytes. Therefore, our findings provide a unified classification of P. cantorii hemocytes and identify the genes related to the stress response, thereby providing a better understanding of the adaptive mechanisms of hibernation.

The relationship between Mute Swan Cygnus olor population trends in Great Britain and environmental change

ABSTRACT Capsule The increase in autumn sowing of crops is probably an additional contributory factor to the national ban on lead angling weights in influencing the large increase in British Mute Swan Cygnus olor numbers since the 1970s. Aims The national population of Mute Swans in Great Britain has more than doubled since the 1970s, and previous correlative analyses of national population changes identified a national ban on lead angling weights in 1987 as the main driver of this change. We examine regional variation in Mute Swan population changes to test the contribution of additional environmental covariates to the observed increase. Methods We explore regional and national variation in Mute Swan population trends to changes in climate, agriculture, water quality, and angling to assess whether the same patterns emerge at different scales. Results Changes in the extent of oilseed rape and wheat, which provide winter food for Mute Swans, showed a consistent positive association with the spatial and temporal pattern of Mute Swan population trends, while a proxy for the expected change in the exposure of swans to lead weights from angling contributed much less. Conclusion The lead weight ban occurred alongside rapid changes in arable cropping area, with swans probably benefitting from both increased food resources and reduced rates of lead ingestion. Our study highlights the value of exploiting both spatial and temporal variation in abundance when exploring potential drivers of population change. Future changes in agricultural policy and practice in Great Britain may influence Mute Swan populations.

Arctic and red fox population responses to climate and cryosphere changes at the Arctic's edge.

Responses of one species to climate change may influence the population dynamics of others, particularly in the Arctic where food webs are strongly linked. Specifically, changes to the cryosphere may limit prey availability for predators. We examined Arctic (Vulpes lagopus) and red fox (V. vulpes) population dynamics near the southern edge of the Arctic fox distribution using fur harvest records from Churchill, Manitoba, Canada between 1955 and 2012. Arctic foxes showed a declining population trend over time (inferred from harvest records corrected for trapping effort), whereas the red fox population trend was relatively stable. The positive relationship between the annual Arctic and red fox harvests suggested interspecific competition did not promote the Arctic fox decline. To investigate alternative mechanisms, we evaluated the relative influence of sea-ice phenology, snow depth, snow duration, winter thaws, and summer temperature on the harvest dynamics of both species in the most recent 32years (1980-2012; n = 29) of our data. Arctic fox harvests were negatively related to the length of time Hudson Bay was free of sea ice. Shorter sea ice duration may reduce access to seal carrion as an alternative winter food source when lemming densities decline. Contrary to our prediction, red fox harvest was not related to summer temperature but was positively related to snow depth, suggesting winter prey availability may limit red fox population growth. Predators have an important ecological role, so understanding the influence of changes in the cryosphere on predator-prey interactions may better illuminate the broader influence of climate change on food-web dynamics.

Лось (Alces alces) на південній межі ареалу: стан популяції Центрального Полісся, хижацтво вовка та вразливість до потепління клімату

In the latter less hot years after the decline in the number of elk (2019–2020), the stabilisation and increasing trend in the number of this species have been observed throughout the study area. Due to migrations, the winter elk population exceeds the summer one and amounts to 2 individuals/thousand hectares (40 individuals; against 1.3 individuals/1 thousand hectares in summer) in the Polissia Reserve, and 1–6 individuals/1 thousand hectares (940 individuals) in the Chornobyl Reserve. Data on the vulnerability of elk to climate change are presented. In hot weather at different times of the year, elks may show signs of heat stress. In summer, elk can be inactive, and in the leafless period, when chased by wolves, they can get heat stress and die. In the heat of the day, elk choose swamps, waterlogged forests with a dense tree canopy and better cooling, which are comfortable for these ungulates in the face of global warming. Climate change causes marshes to dry up and overgrow, reduces the moisture content of habitats, and worsens the fodder capacity of the land. In case of even partial restoration of lowland marshes in the Chornobyl Biosphere Reserve, the reserves of summer and winter food for elk may increase by 2–3 times. In the Polissia Reserve, in 2011–2013, lowland bogs with bush willows (Salix) were restored on fallow land near the Zholobnytsia drainage system, creating highly productive habitats for the elk, which is a promising measure for different areas of Polissia. Climate warming has led to an increase in the red deer (Cervus elaphus) population and a decrease in the elk population in the Polissia, and if no special measures are taken, these trends will intensify. Outside of protected areas, given the lack of a high legal status for wolves (Canis lupus), a strategy for conserving the elk population and reducing predation mortality in combination with other elk habitat management strategies can be recommended to hunting ground users, including limiting poaching, restoring the natural regime of forest fires in reserves, improving winter provision of branch fodder, reducing the disturbance factor, and introducing a ban on staying in the forest with dogs for berry and mushroom pickers.

Irruptions of Bohemian Waxwings in relation to population density and food availability

Bird irruptions are thought to be triggered by a combination of lack of food in the regular distribution range and high population density (push factors). Recent studies have also suggested that irruptions may be drawn towards areas with high food availability (pull factor). The Bohemian Waxwing (Bombycilla garrulus) is an irruptive species with large annual variation in the numbers reaching southern areas during winter. I used long-term (up to 41 years) data on annual number of waxwings observed during breeding in Finland and Sweden, during winter in Norway, Sweden, Denmark, UK and Poland, and data on their main winter food, Rowanberries (Sorbus aucuparia; masting occurs at 2–3 year intervals) from Norway (southern areas) and Finland (overlapping with northern breeding areas) to test the push and pull hypotheses. Winter numbers fluctuated in synchrony over large parts of northern Europe. In years with low food availability in Finland waxwings arrived to southern areas early, and early arrival to southern areas was linked to larger winter numbers in some countries. However, controlling for arrival time to southern areas, numbers were larger when there were more rowanberries in Finland. Thus, irruptions generally occurred with high rowanberry abundance, but sometimes occurred with the combination of low rowanberry abundance and early arrival. There was mixed evidence that irruptions were linked to high breeding population density. There was no support that irruptions were drawn towards high rowanberry abundance in southern areas. In conclusion, waxwing irruptions had complex relationships with food availability, but most irruptions occurred in years with high rowanberry abundance in autumn in northern areas. This is opposite to expectations from the current view that irruptions are triggered by lack of food, but irruptions departing late may still have been triggered by abundant food finally becoming depleted late in winter.

Correction: Long-term winter food supplementation shows no significant impact on reproductive performance in Mountain Chickadees in the Sierra Nevada Mountains

Correction: Long-term winter food supplementation shows no significant impact on reproductive performance in Mountain Chickadees in the Sierra Nevada Mountains

Winter food selection and exploratory behavior vary with natal territory characteristics in wild great tits

Differences in habitat characteristics experienced during rearing associate with variation in a range of behavioral phenotypes such as exploratory behavior, foraging behavior and food selection. The habitat-dependent selection hypothesis predicts that animals develop behavioral characteristics fitted to their rearing environment. Yet, little is known about how habitat characteristics during rearing shape how animals face winter conditions and adjust their winter foraging behavior. The aim of this study was to explore how fine-scale rearing habitat characteristics associate with exploratory behavior, food selection, and foraging performance during winter. For this, we measured habitat characteristics during the breeding season in territories of wild great tits (Parus major) and tested first-year juvenile birds that fledged from these territories for exploratory and foraging behavior at feeders during winter. We found evidence that faster explorers were raised in territories with lower quality habitat characteristics. In addition, fast exploring fledglings visited the feeders significantly more (total visits). Moreover, the rearing environment, via caterpillar availability and tree species composition, determined diet selection during winter in first-year birds. These results show support for the habitat-dependent selection hypothesis, since exploratory behavior as well as food selection during winter associate with habitat features of the rearing territories during development. This pattern can be caused either by the kinds of natural foods prevalent during rearing at these sites or because of intrinsic individual differences. Further experiments are needed to disentangle these two.Significance statementIndividuals vary in how they behaviorally adapt foraging and food selection strategies to the environmental conditions. A number of studies have shown that animals develop behavioral characteristics fitted to their rearing environment. However, how habitat characteristics during rearing shape the foraging strategy that animals use to face winter conditions is still unknown. We studied these links in yearling great tits using automated feeders that recorded their visits during winter. Fledglings with a higher exploratory score were born in territories with lower quality habitat characteristics and visited the feeders more. Furthermore, we found an association between caterpillar availability and tree species composition in the rearing territory of juveniles and their subsequent food selection in winter. Our study indicates that certain environmental conditions might favor the development of particular behaviors in birds and that early nutrition could shape food choice later in life.

Food availability positively affects the survival and somatic maintenance of hibernating garden dormice (Eliomys quercinus)

BackgroundTorpor is an energy saving strategy achieved by substantial reductions of metabolic rate and body temperature that enables animals to survive periods of low resource availability. During hibernation (multiday torpor), the frequency of periodic rewarming—characterised by high levels of oxidative stress—is associated with shortening of telomeres, a marker of somatic maintenance.ObjectivesIn this study, we determined the impact of ambient temperature on feeding behaviour and telomere dynamics in hibernating garden dormice (Eliomys quercinus) over winter. This obligate hibernator prepares for hibernation by accumulating fat stores but can also feed during hibernation.MethodologyFood intake, torpor pattern, changes in telomere length, and body mass change were assessed in animals housed at experimentally controlled temperatures of either 14 °C (i.e., a mild winter) or 3 °C (i.e., a cold winter) over 6 months.ResultsWhen hibernating at 14 °C, dormice experienced 1.7-fold more frequent and 2.4-fold longer inter-bout euthermia, and spent significantly less time torpid, compared to animals hibernating at 3 °C. Higher food intake enabled individuals to compensate for increased energetic costs when hibernating at milder temperatures (14 °C vs. 3 °C), to buffer body mass loss and thus increase winter survival. Interestingly, we observed a significant increase of telomere length over the entire hibernation period, irrespective of temperature treatment.ConclusionWe conclude that higher temperatures during winter, if associated with sufficient food availability, can have a positive effect on the individual’s energy balance and somatic maintenance. These results suggest that winter food availability might be a crucial determinant for the survival of the garden dormouse in the context of ever-increasing environmental temperatures.