Garrulus Glandarius Research Articles

Does presence of top predator improve forest birds' survival and diversity? An ecological case study assessing umbrella conservational impact of tiger using carrion

After hunting, predators tend to leave a large amount of carrion behind. It is widely reported that this resource is commonly used by various species in the ecosystem and is essential for the survival of scavengers, particularly in winter. Although recent studies are focused on mammals, little is known about how this works with facultative scavenger birds, which may lead to a serious underestimation of the key role that top predators such as the Amur tiger (Panthera tigris altaica) play in ecosystems. Here, we conducted a field feeding experiment to quantitatively evaluate the effects of Amur tiger on avian scavengers by simulating their predation residue. The results show that the Corvidae is the main bird species that consumes carrion, while woodpeckers and some insectivorous songbirds also benefit from the remains that Amur tiger leaves behind. We assumed that in winter, if the daily energy demand for the six main scavenger birds completely relied on the predation residues of Amur tiger separately, the prey remains of one Amur tiger could feed about 28 crows, 49 Azure-winged magpies, 61 Eurasian jays, 235 Eurasian nuthatches, 96 Great spotted woodpeckers, or 385 Willow tits. It means that the prey remains of top predators like Amur tiger may be an extremely important resource to avian scavengers and carrion could be a potential ecological indicator of Amur tiger keystone effect. This study provides experimental evidence from the field for the first time, and reveals the ecological mechanism of the role of keystone species of the Amur tiger, i.e., how to indirectly protect other animal groups in the forest ecosystem that have important ecological value for the biodiversity and the health of local forest vegetation through the protection of the Amur tiger.

Eurasian jays (Garrulus glandarius) show episodic-like memory through the incidental encoding of information.

Episodic memory describes the conscious reimagining of our memories and is often considered to be a uniquely human ability. As these phenomenological components are embedded within its definition, major issues arise when investigating the presence of episodic memory in non-human animals. Importantly, however, when we as humans recall a specific experience, we may remember details from that experience that were inconsequential to our needs, thoughts, or desires at that time. This 'incidental' information is nevertheless encoded automatically as part of the memory and is subsequently recalled within a holistic representation of the event. The incidental encoding and unexpected question paradigm represents this characteristic feature of human episodic memory and can be employed to investigate memory recall in non-human animals. However, without evidence for the associated phenomenology during recall, this type of memory is termed 'episodic-like memory'. Using this approach, we tested seven Eurasian jays (Garrulus glandarius) on their ability to use incidental visual information (associated with observed experimenter made 'caches') to solve an unexpected memory test. The birds performed above chance levels, suggesting that Eurasian jays can encode, retain, recall, and access incidental visual information within a remembered event, which is an ability indicative of episodic memory in humans.

Fragmentation and Connectivity in dehesa Ecosystems Associated with Cerambyx spp. Dispersion and Control: A Graph-Theory Approach

Xylophagous insects play a crucial role in forest ecosystems, contributing to population dynamics. The “Cerambyx complex” (CC) constitutes an emerging pest in Mediterranean oak woodlands. We studied the fragmentation and connectivity of holm and cork oak stands in Andalusia (Spain), and the relationships with the current dispersion of CC, as well as the effect on the connectivity and dispersion patterns with the implementation of nests of a predator bird (Garrulus glandarius) to reduce insect populations in highly connected areas. The Kernel Density Estimation (KDE) was used to assess the spatial distribution of CC. Connectivity was assessed using graphs theory (Graphab 2.6) to characterize the importance of patches and linkages for contributing to dispersal. We selected the Eurasian jay (G. glandarius) as a reference bird species to generate “barriers” to the dispersion of the CC. We used the probability of connectivity (PC) and the flux (F) to compare the effect of the introduction of Eurasian jay nets. Results showed an increasing trend in the distribution and incidence of CC during the period 2001–2016, resulting in 7.3% and 13.1% mortality rates for Q. ilex and Q. suber, respectively. The connectivity model using only Q. ilex and Q. suber forests as reference habitats was not enough to explain the distribution of CC. The value of PC and F metrics decreased by 38.09% and 20.59% by introducing 300 nests of Eurasian jay. Our methodology provides a pest management tool using connectivity metrics, which can be integrated with other variables to control pest outbreaks and pest dispersion.

High prevalence of haemosporidian parasites in Eurasian jays

Avian haemosporidians are vector-borne parasites, infecting a great variety of birds. The order Passeriformes has the highest average infection probability; nevertheless, some common species of Passeriformes have been rather poorly studied. We investigated haemosporidians in one such species, the Eurasian jay Garrulus glandarius (Corvidae), from a forest population in Hesse, Central Germany. All individuals were infected with at least one haemosporidian genus (overall prevalence: 100%). The most common infection pattern was a mixed Haemoproteus and Leucocytozoon infection, whereas no Plasmodium infection was detected. Results on lineage diversity indicate a rather pronounced host-specificity of Haemoproteus and Leucocytozoon lineages infecting birds of the family Corvidae.

Human urine does not protect acorns against predation by the wood mouse (Apodemus sylvaticus): a field study with video recording

Direct seeding is a revegetation method that can offer great advantages for forest restoration, but suffers the drawback of seed loss due to granivorous rodents. Thus, to make direct seeding a useful and scalable forest restoration method, we need to find ways to protect seeds against rodents. Scents produced by carnivorous or omnivorous animals that elicit a fear response on rodents are a promising group of substances that can be used to protect seeds and that have demonstrated effectiveness in a number of cases. Here, I test if human urine has a protective effect on Holm oak (Quercus ilex) acorns against predation by mice. Human urine would be much easier and cheaper to obtain than the urine of other animals, providing the possibility, if effective, to scale the application of a repellent substance. I set up a field experiment in an area with high wood mouse (Apodemus sylvaticus) abundance and used eight urine donors. Neither urine nor donor had any effect. Acorn removal was very fast and high, reaching 97.2% after 7 days. Video recording with camera traps showed that the wood mouse was the main predator, but the Eurasian jay also removed acorns. I conclude that human urine is not useful as a repellent against mice and suggest to focus efforts in finding other substances to repel seed predators.

Do cuckoo calls affects red-backed shrike settlement pattern? An experimental approach

Birds select breeding territories by assessing territory quality and considering predation pressure. However, in many small passerines, brood parasitism may also play an important role in territory occupancy. Settlement decisions are made under time pressure, especially for late migrants. An example of late migrants is the red-backed shrike Lanius collurio, a species wintering in sub-tropical Africa, which serves as a host for the common cuckoo Cuculus canorus and arrives in territories a few days later than their brood parasite. We expected that arriving red-backed shrikes avoided territories with common cuckoo presence. Then, we tested how experimentally provided artificial playback calls of the common cuckoo and woodpigeon (treated as control) affected the probability of red-backed shrike settlement. In the breeding season 2021, we observed 279 red-backed shrike territories to assess the effect of playback of common cuckoo calls on their host presence. Moreover, we adopt information on shrike territories collected in previous years to establish territory quality, measured by occupancy pattern over years. Each of these places was also checked for the presence of corvids, which are predators of shrike nests. We did not find difference with lower preference of shrikes towards cuckoo calls and to pigeon calls Columba columbus, what suggest the human presence and manipulation in the territories during experiments with recorders should be incorporated as an important factor to understanding shrikes’ settlement behaviour. What is interesting we found no negative effect of corvids (jay Garrulus glandarius) in control territories. However, shrike territories where cuckoo calls were emitted and where the presence of corvids was found were less likely to be inhabited by shrikes. Therefore, territory quality, human presence enhanced by nest predators, is an important factor affecting host–parasite interactions.

Avian trematodes of central European corvids are heterogeneous regarding preferences for host species and age.

Corvids are highly adaptive birds that respond well to anthropogenic changes in their environment. Trematode communities of corvids were studied mainly in the 1950s through 1970s in regularly flooded parts of the Volga River delta in Russia; more recent studies and data from other regions where the corvids are in less contact with postflooding habitats are limited. Data for Corvus corax were lacking. Using our samples obtained from 1963 to 2023, we performed a large-scale analysis of trematode species composition and community structure in Corvus frugilegus, Corvus cornix, C. corax, Coloeus monedula, Pica pica, and Garrulus glandarius; all originated from the Czech Republic. We identified corvids as hosts of mutually overlapping component communities of only a few species of trematodes (Brachylecithum lobatum, Lyperosomum petiolatum, Lyperosomum longicauda, Tamerlania zarudnyi, Urogonimus macrostomus), with the presence of many rare and incidental findings of other trematode species. Only a few species used corvids as their core hosts (L. longicauda and B. lobatum). Trematode component communities in first-year birds included Prosthogonimus cuneatus, Prosthogonimus ovatus, Plagiorchis asperus, and Morishitium dollfusi due to an increased share of insects (intermediate hosts of Prosthogonimus and Plagiorchis) and snails (intermediate hosts of Morishitium) in the diet of juveniles. The trematode component communities of corvid species overlapped but were heterogeneous at the level of host individuals, likely reflecting differences in food sources related to the respective host ages and nesting sites.

Social influences on delayed gratification in New Caledonian crows and Eurasian jays.

Self-control underlies goal-directed behaviour in humans and other animals. Delayed gratification - a measure of self-control - requires the ability to tolerate delays and/or invest more effort to obtain a reward of higher value over one of lower value, such as food or mates. Social context, in particular, the presence of competitors, may influence delayed gratification. We adapted the 'rotating-tray' paradigm, where subjects need to forgo an immediate, lower-quality (i.e. less preferred) reward for a delayed, higher-quality (i.e. more preferred) one, to test social influences on delayed gratification in two corvid species: New Caledonian crows and Eurasian jays. We compared choices for immediate vs. delayed rewards while alone, in the presence of a competitive conspecific and in the presence of a non-competitive conspecific. We predicted that, given the increased risk of losing a reward with a competitor present, both species would similarly, flexibly alter their choices in the presence of a conspecific compared to when alone. We found that species differed: jays were more likely to select the immediate, less preferred reward than the crows. We also found that jays were more likely to select the immediate, less preferred reward when a competitor or non-competitor was present than when alone, or when a competitor was present compared to a non-competitor, while the crows selected the delayed, highly preferred reward irrespective of social presence. We discuss our findings in relation to species differences in socio-ecological factors related to adult sociality and food-caching (storing). New Caledonian crows are more socially tolerant and moderate cachers, while Eurasian jays are highly territorial and intense cachers that may have evolved under the social context of cache pilfering and cache protection strategies. Therefore, flexibility (or inflexibility) in delay of gratification under different social contexts may relate to the species' social tolerance and related risk of competition.

Wild and partially synanthropic bird yeast diversity, in vitro virulence, and antifungal susceptibility of Candida parapsilosis and Candida tropicalis strains isolated from feces.

Yeast complexes in the fecal samples of wild (Dendrocopos major, Picus viridis) and partially synanthropic (Bombycilla garrulus, Garrulus glandarius, Pica pica, and Pyrrhula pyrrhula) birds were studied in a forest ecosystem during winter. A total of 18 yeast species were identified: 16 ascomycetes and two basidiomycetes belonging to five subphyla of fungi: Saccharomycotina (15), Pezizomycotina (1), Agaricomycotina (1), and Pucciniomycotina (1). Most yeast species were found in the fecal samples of P. pyrrhula (Candida parapsilosis, C. zeylanoides, Debaryomyces hansenii, Hanseniaspora uvarum, Metschnikowia pulcherrima, Meyerozyma carpophila, M. guilliermondii, Rhodotorula mucilaginosa); the lowest number of yeast species was observed in the feces of B. garrulus (C. parapsilosis, C. zeylanoides, Met. pulcherrima, and Rh. mucilaginosa). The opportunistic species of the genus Candida were found only in feces of partially synanthropic birds: C. parapsilosis was observed in the feces of B. garrulus, G. glandarius, P. pica, and P. pyrrhula; its relative abundance was 69.3%, 49.1%, 10.5%, and 1.1%, respectively; C. tropicalis was observed in the feces of P. pica and G. glandarius; its relative abundance was 54.6% and 7.1%, respectively. Strains of C. parapsilosis and C. tropicalis isolated from the feces of partially synanthropic birds were evaluated for their susceptibility to conventional antifungal agents (fluconazole, voriconazole, amphotericin B) and hydrolytic activity. A total of 160 strains were studied. Resistance to fluconazole was detected in 86.8% of C. parapsilosis strains and in 87% of C. tropicalis strains; resistance to voriconazole was detected in 71.7% of C. parapsilosis and in 66.7% of C. tropicalis strains, and the lowest percentage of resistant strains was detected to amphotericin B, 2.8% and 3.7% in C. parapsilosis and C. tropicalis strains, respectively. Multiresistance was detected in one strain of C. parapsilosis isolated from P. pica feces and in one strain of C. tropicalis isolated from G. glandarius feces. Phospholipase and hemolysin activities in the strains of C. parapsilosis were low (mean Pz values of 0.93 and 0.91, respectively); protease activity was moderate (mean Pz value of 0.53). The ability to produce hydrolytic enzymes was higher in the isolated strains of C. tropicalis. The mean Pz values of phospholipase and hemolysin activities were moderate (mean Pz values of 0.63 and 0.60, respectively), whereas protease activity was high (mean Pz value of 0.32). Thus, wild and partially synanthropic birds play an important role in disseminating of various yeast species. These yeasts can enter the topsoil via feces and contribute to the formation of allochthonous and uneven soil yeast diversity in natural ecosystems. In addition, partially synanthropic birds can be vectors of virulent strains of opportunistic Candida species from urban environments to natural biotopes.

Use of viscera from hunted roe deer by vertebrate scavengers in summer in central European mountainous mixed forest

Carrion is a valuable resource in forests, providing sustenance for vertebrate and invertebrate scavenger communities and contributing to ecosystem functions, such as nutrient cycling. Intensive ungulate hunting, and thereby extraction of carcasses, removes large quantities of potential carrion from the system, denying a valuable resource from scavenger fauna. It may be possible to reduce the loss and negative consequences to forest biodiversity by retaining evisceration residues from hunted deer, where full carcasses cannot be retained. However, what roll evisceration residues play as a resource for scavengers in temperate forests is not well understood. In this study, we exposed 47 carrion samples from hunted roe deer, in front of triple sets of camera traps, to examine how hunting remains are removed and fed upon by vertebrate scavengers. Overall, 70% of the samples were completely removed from experimental sites by vertebrates. We detected twelve vertebrate taxa feeding on evisceration residues, including martens (Martes spp.), red kites Milvus milvus and garden dormice Eliomys quercinus. Common buzzards Buteo buteo and Eurasian jays Garrulus glandarius were the most frequent feeders on carrion samples, while red foxes Vulpes vulpes displaced the largest proportion of samples. Finally, we found a range of insectivorous bird and mammal species using hunting remains as a source for invertebrate prey, while not scavenging on the remains directly. We demonstrate that evisceration residues can be a valuable resource for a wide range of taxa and suggest that viscera retention from hunted game may contribute to resource provisioning for scavengers in forest ecosystems.

Spatial decision-making in acorn dispersal by Eurasian jays around the forest edge: Insights into oak forest regeneration mechanisms

Seed dispersal is key to forest regeneration and often depends on the behavior of seed scatter-hoarding animals. However, our understanding of the decision-making of scatter-hoarders and how vegetation structure at different spatial scales affects dispersal patterns remains limited. We studied seed dispersal at the forest edge across multiple spatial scales (habitat, sub-habitat, microsites) between and within habitats with distinct vegetation structure. Our model system is a mixed-oak forest dominated by holm oak (Quercus ilex) and an adjacent shrubland dominated by the shrub Retama sphaerocarpa. For three years, we tracked the movement of acorns by a keystone scatter-hoarder, the Eurasian jay (Garrulus glandarius). At the coarse scale, jays did not show a preference for caching acorns either in the forest or in the shrubland when the source tree was within the forest. However, when the source tree was on the forest edge or was an isolated oak tree in the shrubland at < 200 m from the forest, jays showed a preference for caching in the forest. Conversely, when isolated oak trees were > 200 m from the forest, all acorns were dispersed in the shrubland. Dispersal distances were shorter within the forest than within the shrubland. At an intermediate scale, within the shrubland jays preferred to cache acorns under large retamas while avoiding gaps. In the forest, jays also avoided gaps and preferred certain woody species and vertical vegetation structures, although these preferences varied across feeders. At the finest scale, jays selected stones as cache microsites. Thus, the selection of acorn caching sites followed a hierarchical and selective top-down process across different spatial scales. The position of the source trees in the landscape determined habitat preference and dispersal distance. We detected different preferences in response to similar vegetation structure and composition, indicating that the decision-making process is flexible at an intermediate scale that generates diverse spatial patterns of dispersal. This study sheds light on the intricate decision-making process of seed caching by scatter-hoarders, and the consequences for the spatial patterns of seed dispersal as well as the expansion and regeneration of oak forests.

The Use of the Microstructure of Coverling Feathers in the Systematics of Ground Jays (Aves, Corvidae: &lt;i&gt;Podoces, Eupodoces&lt;/i&gt;)

Using scanning electron microscopy, new data on the microstructure of the definitive coverling feathers of all four species of ground jays Podoces pleskei, P. panderi, Eupodoces hendersoni and E. biddulphi and eight other species of Corvidae were obtained: Ptilostomus afer, Garrulus glandarius, Perisoreus infaustus, Corvus cornix, Cyanopica cyana, Nucifraga caryocatactes, Pica pica and Pyrrhocorax pyrrhocorax. Comparative morphological analysis involving previously published data on the microstructure of the pen-feathers of these species, as well as Corvus monedula, C. frugilegus, C. corax, revealed a number of feather microstructures specific to ground jay species, as well as differences between Podoces and Eupodoces, which confirms their genus status, possible relationship with G. glandarius and Pt. afer, as well as the preservation of ancestral features in P. pleskei.

Temporal occurrence and species composition of birds on artificial feeding sites maintained for game mammals in the Dinaric Mountains, Slovenia

Artificial feeding is a widely used management tool, but it often attracts nontarget species, including birds, to permanent feeding sites. This study used camera traps to monitor the presence of birds at selected sites used for bear management in Dinaric forest. A large number of bird species (35) were recorded, representing roughly half of all species breeding in the surrounding area. These species were grouped based on monthly and hourly presence, and corresponded to food groups, with most belonging to granivores or scavengers. Some species, such as Pigeons (Columba sp.), Raven (Corvus corax) and Buzzard (Buteo buteo), adapted their presence to the availability of food at the feeding sites, while others were not affected by this. Both Chaffinches (Fringilla coelebs) and Jays (Garrulus glandarius) frequented the feeding sites, but their temporal presence was influenced by their biology rather than by food availability. The Sparrowhawk (Accipiter nisus) also adapted its presence to food availability, and its presence was closely associated with that of the Jay. This study confirms the temporal differences in the use of feeding sites by birds and mammals, which is likely due to their different biology and past management. This can be used to make wildlife management more efficient and reduce the undesirable effects of artificial feeding.

Low Rate of Pre-Dispersal Acorn Predation by Eurasian Jays Garrulus glandarius during Non-Mast Years

Mast-seeding is widely considered to be an adaptation that minimizes seed predation. The superabundance of seeds during mast years greatly exceeds the capacity of seed predators to consume them. These notions were based on research on food specialists such as insects and rodents. However, mast-seeding may have different impact on the behavior of corvids that are food generalists. The Eurasian Jay Garrulus glandarius is a widespread scatter-hoarding corvid that uses acorns as a food reserve for winter. In mast-years, the birds are supposed to be satiated by the greater seed supply and are able to store their surplus, acting as dispersal agents, whereas in poor crop seasons they use most of the crop for current consumption and thus become seed predators. In such a situation, a dispersal agent may become a seed predator, and vice versa. The main task of this study was to determine the levels of pre-dispersal acorn predation by Jays during non-mast years to verify the notion that under such conditions Jays act mostly as seed consumers. During two consecutive non-mast years, tagged acorns were radio-tracked and the acorns' fate (cached or eaten) was assessed. We found extremely low pre-dispersal acorn predation by Jays (0.9%). The possible reason is that temperatures in period of acorns collecting (September–October) are high enough to allow invertebrates to remain active, so the Jays may supplement their diet with insects and also fleshy fruits. Therefore, almost all acorns were cached and scatter-hoarding Jays provided effective seed dispersal, with extremely low consumption of acorns.

Bird communities after 37 years in a rural area of NW Spain

In a globalized world, changes in human activities are negatively affecting biodiversity at different scales. Long-term monitoring of bird communities can inform about changes in biodiversity over time. We explored how bird species richness, and abundance changed after a 37-year period at 5 sites in O Courel Mountains, a well conserved region of NW Spain. We also analyzed the abundance changes over time in the 15 most abundant species and whether these changes relate to the phenotypes of these species. Repeated bird surveys were performed in the same locations of five different sites in 1977 and 2014. Our results showed species richness and overall bird abundance did not change after 37 years within the five studied sites. Although, within species analyses showed 8 species changed their abundances. Overall, Cyanistes caeruleus, Garrulus glandarius, Parus major, Prunella modularis and Sylvia atricapilla increased their abundances and Erithacus rubecula, Phylloscopus ibericus, and Troglodytes troglodytes decreased over time. We did not find any relationship between the change in species abundances and bird phenotypes. This study shows that, despite the specific changes in the abundance of eight species over nearly four decades, overall bird species richness and abundance may be maintained in well preserved natural areas.

Spatial Overlap and Habitat Selection of Corvid Species in European Cities

Understanding habitat and spatial overlap in sympatric species of urban areas would aid in predicting species and community modifications in response to global change. Habitat overlap has been widely investigated for specialist species but neglected for generalists living in urban settings. Many corvid species are generalists and are adapted to urban areas. This work aimed to determine the urban habitat requirements and spatial overlap of five corvid species in sixteen European cities during the breeding season. All five studied corvid species had high overlap in their habitat selection while still having particular tendencies. We found three species, the Carrion/Hooded Crow, Rook, and Eurasian Magpie, selected open habitats. The Western Jackdaw avoided areas with bare soil cover, and the Eurasian Jay chose more forested areas. The species with similar habitat selection also had congruent spatial distributions. Our results indicate that although the corvids had some tendencies regarding habitat selection, as generalists, they still tolerated a wide range of urban habitats, which resulted in high overlap in their habitat niches and spatial distributions.

A case report of an Eurasian jay (Garrulus glandarius) attacking an incubating adult and depredating the eggs of the Japanese tit (Parus minor).

In May 2021, we opportunistically observed one Eurasian jay (Garrulus glandarius) attacking an adult incubating Japanese tit (Parus minor) and depredating nine tit eggs at a nest box where a woodpecker had greatly enlarged the entrance. After the predation event, the Japanese tits abandoned the nest. We recommend that when using artificial nest boxes to protect hole-nesting birds, the appropriate entrance size should be proportional to the body size of the target species. This observation gives us a better understanding of the potential predators of secondary hole-nesting birds.

Mirror stimulation in Eurasian jays (Garrulus glandarius).

Mirror exposure elicits a wide range of behavioral responses, some of which have been considered as part of possible evidence of mirror self-recognition (MSR). These responses can range from social behaviors, indicating that an animal considers its own reflection as a conspecific, to mirror-guided and self-directed actions. Evidence of MSR has been found categorically in only a few species, such as in magpies, chimpanzees, horses, and elephants. Evidence in corvids is currently debated due to inconsistent findings. In this study, we investigated the reaction of Eurasian jays when presenting them with three mirror-stimulation tasks. Based on the overall behavioral patterns across these three tasks, conclusions about birds' understanding of a reflective surface, and their perception of the reflection as either themselves or as a conspecific, appear premature. We highlight how the high neophobia of corvids and other methodological constraints might have hindered the likelihood to approach and explore a mirror, preventing the emergence of behaviors typically associated with MSR. Furthermore, we discuss how motivational factors, methodological constraints and species differences should be considered when interpreting behavioral responses to mirrors.

How the Eurasian Jay Expands its Color Palette by Optimizing Multiple Scattering (Advanced Optical Materials 4/2023)

In article number 2202210, Deok-Jin Jeon, Jong-Souk Yeo, and co-workers elucidate how thickness changes in feather nanostructures create periodic color variations in Eurasian jay wing covert feathers. Multiple scattering in the biological system expands the natural color palette by extending reflection to longer wavelengths in thicker spongy layers. White feather regions have two times thicker nanostructure compared to the blue ones. Inspired by the Eurasian jay design solution, biomimicry of periodic color variation is demonstrated in a synthetic context.

An integrated animal tracking technology combining a GPS tracking system with a UAV

Abstract Global Position System (GPS) tags are widely used in animal tracking to address far‐ranging ecological, behavioural and conservation‐related questions. However, GPS tags with transmitting functions via Global System for Mobile communications (GSM) and long‐lasting batteries are too cumbersome for animals with small body sizes. In addition, GSM is expensive with strict signal limitations in remote areas. Downloading locations from small GPS tags also requires animal recapture, which can result in large workloads. Combined, these problems limit the use of GPS tags in tracking small animals. To overcome these challenges, we present an integrated technology to pinpoint animal locations, especially those of medium‐ and small‐sized species. Our system consists of 3.7 g solar‐powered GPS tags (Nano), whose sampling frequency can be changed flexibly, and a combination of a receiver and an unmanned aerial vehicle (UAV) to retrieve data. The UAV carries the receiver that can retrieve data from Nanos via Bluetooth. Data are uploaded to a platform via GSM by the receiver and then downloaded by users in real time. Users can also directly download data from tags or the receiver via Bluetooth. We conducted stationary and field tests to assess the system's performance in Thousand Island Lake, China. Stationary tests were conducted at eight sites near the buildings, in open fields and on an island. Nanos can transmit data to the receiver within distances of 600–1000 m and at speeds of 6–72 records/s. The mean accuracy was 10.44–23.32 m and the fix success rates (FSRs) were larger than 97%. In field tests, we captured and attached Nanos on six Eurasian jays Garrulus glandarius. The FSRs were larger than 98%. Using the UAV reduced the time spent in field. Our system is labour‐saving and accurate in locating animals larger than 80 g as tested in a land‐bridge island system. Bluetooth transmission assisted by the UAV can overcome signal limitations and landscape blocks, and has the potential to be applied in inaccessible landscapes. The large memory of Nanos also allows for the retrieval of data from migratory species with strong site fidelity on their returns.