A low‐cost radio frequency identification device for ornithological research

ABSTRACT Radio frequency identification (RFID) technology can be used to implement automated bird‐monitoring systems and, therefore, could be of use to field ornithologists. However, the cost of a large‐scale RFID network can be prohibitive for those with limited research budgets. We describe a simple RFID reader/data logger that can be constructed for less than $40 (excluding tools and a battery). This device can be mounted on birdfeeders, nest boxes, nests, or any location repeatedly visited by birds fitted with small RFID tags (i.e., passive integrated transponder or PIT tags). To demonstrate the potential of this low‐cost RFID reader, we monitored the use of feeders by wintering songbirds in central New York and generated a data set consisting of more than 500,000 feeder visits over 5 mo. These data revealed several interesting behaviors, including high visitation rates by some individuals (>200 visits per day), long‐distance movements between feeders (emigration and immigration), and species‐specific patterns of feeder use. Although the system performed well in relatively harsh winter conditions, occasional battery failures and water damage led to some loss of data. Nevertheless, we amassed over 8000 h of monitoring by investing approximately 6 h of labor per week. In addition to recording tag numbers and time stamps, the RFID reader can interface with sensors and actuators, permitting the collection of additional data (such as body mass) and allowing control of motors or solenoids to interact with targeted individuals. RFID technology has great potential for use in a variety of ornithological studies, and we hope our device helps make this technology more accessible.     

Applications of radio frequency identification (RFID) in ornithological research: a review

ABSTRACT Radio frequency identification (RFID) technology allows the unique identification of individuals and automated recording of the presence of tagged birds at fixed locations. Investigators have used RFID technology to examine questions related to pair formation, feeding rates, incubation behavior, prospecting behavior by nonbreeding birds, temporal changes in body condition, postfledging movements, dispersal, homing behavior, and other areas of ornithological interest. This technology can enable researchers to explore novel areas of inquiry and gather previously unobtainable quantities of information, allowing birds to record their own behavior without repeated capture and handling. In addition, RFID technology can be linked with other instruments, such as automated weighing devices, video cameras, infrared beams to detect the direction of movement, and temperature loggers, to collect additional data. New, inexpensive RFID technology has removed cost as a major constraint to the wider implementation of RFID in ornithological research. Because the technology requires that focal individuals come near (<10 cm) a reading antenna, RFID is not appropriate for all study systems and research questions. However, integrating RFID technology with additional instrumentation platforms and external data sets will continue to revolutionize studies of avian biology and behavior.     

Terrestrial Passive Integrated Transponder Antennae for Tracking Small Animal Movements

ABSTRACT Measuring terrestrial movements of small animals poses a substantial technological challenge. We developed very long (up to 130 m) passive integrated transponder (PIT) detectors with which we tracked salamanders (Caudata) migrating from breeding ponds to their upland habitat >200 m away. In all 60 trials, salamanders were detected when released near the antennae. In a second test, we tracked 7 of 14 tagged marbled salamanders (Ambystoma opacum) migrating >65 m, well beyond the area protected by existing wetland buffer regulations in Massachusetts, USA. The mean rate of movement for these salamanders (x̄ = 0.9 m/min; SE = 0.1 m/min) was substantially higher than rates of movement reported for related salamanders with radio-implants. These PIT antennae offer researchers a means to study small animal movements with less disruption of the animals’ natural movement patterns than is caused by other available techniques.     

Causes and consequences of individual variation in the extent of post‐juvenile moult in the blue tit Cyanistes caeruleus (Passeriformes: Paridae)

Moult, comprising the growth or replacement of feathers in birds, is an energetically demanding process. As a result, in many species, the extent of the post‐juvenile moult can vary substantially. However, the reasons underlying this variation remain poorly understood, and the potential life‐history consequences of variation in moult extent are even less clear. In the present study, we aimed to use individual‐specific data to identify factors affecting the extent of the post‐juvenile moult in a population of over 2500 blue tits Cyanistes caeruleus Linnaeus 1758, and to assess the consequences of individual variation in moult extent on reproduction in the first year of life. There was a substantial sex difference in post‐juvenile moult extent, with males moulting more extensively than females. Putative immigrant birds had moulted on average less than those born locally. However, there was little evidence of carry‐over effects of the natal environment on moult extent because we found no relationship between moult extent and fledging date or nestling mass. Evidence that moult extent, and hence feather brightness, affected subsequent reproductive success was limited. Moult extent had no effect on recruitment in males, although female recruits had moulted significantly less than nonbreeders. Because it was not influenced by features of the natal environment, moult extent may not be an honest signal of individual quality in C. caeruleus. As a result, the potential consequences of variation in moult extent for fitness are likely to be small.     

Activity rhythm and action range of workers of the invasive hornet predator of honeybees Vespa velutina,measured by radio frequency identification tags

In social insects, the activity rhythm of foragers and their action range determinate the activity of the colony. In vespids, which are mostly predators, the foraging range of workers determines their maximum predation pressure round the nest. One of these species, Vespa velutina, a recently invasive species introduced into Europe, exerts a strong predation on honeybees at the hive. Therefore, the definition of its activity rhythm and spatial range of predation is of primary importance. Using radio frequency identification tags (RFID), two experiments were carried out to (a) determine their return ability (called homing) in releasing 318 individuals at different distance from their colony and (b) monitor their foraging activity rhythm and the duration of their flights based on 71 individuals followed 24 hr/24 during 2 months. The homing ability of V. velutina was evaluated to be up to 5,000 m and was not affected by the cardinal orientation of release point. The lag time to return to the nest increased with the distance of release. Most of the flight activity took place between 07:00 a.m. and 08:00 p.m., hornets doing principally short flights of less than an hour. Foraging range was thus estimated ca. 1,000 m around the nest. This study of V. velutina assisted by RFID tags provides for the first time a baseline for its potential foraging distance that increase our knowledge of this species to (a) refine more accurately models for risk assessment and (b) define security perimeter for early detection of predation on invasion front.     

Evaluating the accuracy and biological meaning of visits to RFID‐enabled bird feeders using video

Radio‐frequency identification (RFID) technology has gained popularity in ornithological studies as a way to collect large quantities of data to answer specific biological questions, but few published studies report methodologies used for validating the accuracy of RFID data. Further, connections between the RFID data and the behaviors of interest in a study are not always clearly established. These methodological deficiencies may seriously impact a study''s results and subsequent interpretation. We built RFID‐equipped bird feeders and mounted them at three sites in Tompkins County, New York. We deployed passive integrated transponder tags on black‐capped chickadees, tufted titmice, and white‐breasted nuthatches and used a GoPro video camera to record the three tagged species at the feeders. We then reviewed the video to determine the accuracy of the RFID reader and understand the birds’ behavior at the feeders. We found that our RFID system recorded only 34.2% of all visits by tagged birds (n = 237) and that RFID detection increased with the length of a visit. We also found that our three tagged species and two other species that visited the feeders, American goldfinch and hairy woodpecker, retrieved food in 79.5% of their visits. Chickadees, titmice, nuthatches, and woodpeckers spent, on average, 2.3 s at feeders to collect one seed per visit. In contrast, goldfinches spent an average of 9.0 s at feeders and consumed up to 30 seeds per visit. Our results demonstrate the importance of confirming detection accuracy and that video can be used to identify behavioral characteristics associated with an RFID reader''s detections. This simple—yet time‐intensive—method for assessing the accuracy and biological meaning of RFID data is useful for ornithological studies but can be used in research focusing on various taxa and study systems.     

Measuring the drinking behaviour of individual pigs housed in group using radio frequency identification (RFID)

Changes in the drinking behaviour of pigs may indicate health, welfare or productivity problems. Automated monitoring and analysis of drinking behaviour could allow problems to be detected, thus improving farm productivity. A high frequency radio frequency identification (HF RFID) system was designed to register the drinking behaviour of individual pigs. HF RFID antennas were placed around four nipple drinkers and connected to a reader via a multiplexer. A total of 55 growing-finishing pigs were fitted with radio frequency identification (RFID) ear tags, one in each ear. RFID-based drinking visits were created from the RFID registrations using a bout criterion and a minimum and maximum duration criterion. The HF RFID system was successfully validated by comparing RFID-based visits with visual observations and flow meter measurements based on visit overlap. Sensitivity was at least 92%, specificity 93%, precision 90% and accuracy 93%. RFID-based drinking duration had a high correlation with observed drinking duration (R²=0.88) and water usage (R²=0.71). The number of registrations after applying the visit criteria had an even higher correlation with the same two variables (R²=0.90 and 0.75, respectively). There was also a correlation between number of RFID visits and number of observed visits (R²=0.84). The system provides good quality information about the drinking behaviour of individual pigs. As health or other problems affect the pigs’ drinking behaviour, analysis of the RFID data could allow problems to be detected and signalled to the farmer. This information can help to improve the productivity and economics of the farm as well as the health and welfare of the pigs.     

Relationships between range access as monitored by radio frequency identification technology,fearfulness, and plumage damage in free-range laying hens

Severe feather-pecking (SFP), a particularly injurious behaviour in laying hens (Gallus gallus domesticus), is thought to be negatively correlated with range use in free-range systems. In turn, range use is thought to be inversely associated with fearfulness, where fearful birds may be less likely to venture outside. However, very few experiments have investigated the proposed association between range use and fearfulness. This experiment investigated associations between range use (time spent outside), fearfulness, plumage damage, and BW. Two pens of 50 ISA Brown laying hens (n=100) were fitted with radio frequency identification (RFID) transponders (contained within silicone leg rings) at 26 weeks of age. Data were then collected over 13 days. A total of 95% of birds accessed the outdoor run more than once per day. Birds spent an average duration of 6.1 h outside each day over 11 visits per bird per day (51.5 min per visit). The top 15 and bottom 15 range users (n=30), as determined by the total time spent on the range over 13 days, were selected for study. These birds were tonic immobility (TI) tested at the end of the trial and were feather-scored and weighed after TI testing. Birds with longer TI durations spent less time outside (P=0.01). Plumage damage was not associated with range use (P=0.68). The small group sizes used in this experiment may have been conducive to the high numbers of birds utilising the outdoor range area. The RFID technology collected a large amount of data on range access in the tagged birds, and provides a potential means for quantitatively assessing range access in laying hens. The present findings indicate a negative association between fearfulness and range use. However, the proposed negative association between plumage damage and range use was not supported. The relationships between range use, fearfulness, and SFP warrant further research.     

Social networks based on frequency of roost cohabitation do not reflect association rates of Myotis lucifugus within their roosts

Bats are a group of mammals well known for forming dynamic social groups. Studies of bat social structures are often based upon the frequency at which bats occupy the same roosts because observing bats directly is not always possible. However, it is not always clear how closely bats occupying the same roost associate with each other, obscuring whether associations result from social relationships or factors such as shared preferences for roosts. Our goal was to determine if bats cohabitating buildings were also found together inside roosts by using anti‐collision technology for PIT tags, which enables simultaneous detection of multiple tags. We PIT‐tagged 293 female little brown myotis (Myotis lucifugus) and installed antennas within two buildings used as maternity roosts in Yellowstone National Park. Antennas were positioned at roost entryways to generate cohabitation networks and along regions of attic ceilings in each building to generate intraroost networks based on proximity of bats to each other. We found that intraroost and cohabitation networks of buildings were significantly correlated, with the same bats tending to be linked in both networks, but that bats cohabitating the same building often roosted apart, leading to differing assessments of social structure. Cohabitation rates implied that bats associate with a greater number of their roost‐mates than was supported by observations within the roost. This caused social networks built upon roost cohabitation rates to be denser, smaller in diameter, and contain nodes with higher average degree centrality. These results show that roost cohabitation does not reflect preference for roost‐mates in little brown myotis, as is often inferred from similar studies, and that social network analyses based on cohabitation may provide misleading results.     

Smart Labels for Waste and Resource Management

This article explores the potential of RFID (radio frequency identification device) for improving the current waste and resource management system in Switzerland. It presents the following three possible options for utilizing RFID tags to support waste management processes: "at source automation" (using a "smart" trash can), "end of pipe I" (combination of the current system with an additional separation of recyclables before incineration), and "end of pipe II" (replacement of the current recycling infrastructure by sorting at the incineration plant). These options tackle the waste and resource management chain during different processes (i.e., waste generation, waste separation, and treatment). Based on an MFA (material flow analysis), we performed a multicriteria assessment of these options with experts from the waste management sector.
The assessment of ten experts in the waste management field regarding the proposed options for batteries and electrical appliances showed that, from an ecological perspective, the implementation of RFID in waste management would be desirable and would lead to an improvement in the current recycling rate in Switzerland for the goods studied. From an economic perspective, new investments would be required in the range of 1 to 5 times the maintenance costs of the current separate collection system. From a social perspective, the utilization of RFID tags in the waste management process was ambiguous. In particular, the end of pipe II option would, on the one hand, significantly improve convenience for consumers. On the other hand, experts see privacy and, what is more, social responsibility as being under threat. The experts considered the ecological and social aspects to be more relevant than the economic ones, preferring the end of pipe I option over the other options and the status quo.     

Feasibility of Using Radio Frequency Identification to Facilitate Individual Producer Responsibility for Waste Electrical and Electronic Equipment

Regulatory measures that hold producers accountable for their products at end of life are increasingly common. Some of these measures aim at generating incentives for producers to design products that will be easier and cheaper to recover at the postconsumer stage. However, the allocation of recovery costs to individual producers, which can facilitate realization of the goals of these policies, is hindered by the practical barrier of identification and/or sorting of the products in the waste stream. Technologies such as radio frequency identification (RFID) can be used for brand or model recognition in order to overcome this obstacle. This article assesses the read rate of RFID technology (i.e., the number of successful retrievals of RFID tag data [“reads”] in a given sample of tagged products) and the potential role of RFID tags in the management of waste electrical and electronic equipment (WEEE) at current levels of technical development. We present the results of RFID trials conducted at a civic amenity site in the city of Limerick, Ireland. The experiment was performed for fixed distances up to 2 meters on different material substrates. In the case of white goods (i.e., large household appliances), a 100% read rate was achieved using an RFID handheld reader. High read rates were also achieved for mixed WEEE. For a handheld scan of a steel cage containing mixed WEEE, read rates varied from 50% to 73% depending on the ultrahigh frequency (UHF) metal mount tag employed and the relative positioning of the tags within the cage. These results confirm that from a technical standpoint, RFID can achieve much greater brand or model identification than has been considered feasible up to now, and thus has a role to play in creating a system that allocates recovery costs to individual producers.