Passive Integrated Transponder Tag Reader Research Articles

Food availability leads to more connected contact networks among peridomestic zoonotic reservoir hosts.

The North American deermouse (Peromyscus maniculatus) is a reservoir host for many zoonotic pathogens. Deermice have been well studied, but few studies have attempted to understand social interactions within the species despite these interactions being key to understanding disease transmission. We performed an experiment to determine if supplemental food or nesting material affected social interactions of deermice and tested if interactions increased with increasing population density. We constructed three simulated buildings that received one of three treatments: food, nesting material, or control. Mice were tagged with passive integrated transponder (PIT) tags, and their movement in and out of buildings was monitored with PIT tag readers. PIT tag readings were used to create contact networks, assuming a contact if two deermice were in the same building at the same time. We found that buildings with food led to contact networks that were approximately 10 times more connected than buildings with nesting material or control buildings. We also saw a significant effect of population density on the average number of contacts per individual. These results suggest that food supplementation which is common in peridomestic settings, can significantly increase contacts between reservoir hosts, potentially leading to increased transmission of zoonotic viruses within the reservoir host and from reservoir hosts to humans.

Using Radio‐Frequency Identification Technology to Monitor Eurasian Beavers

ABSTRACTThe use of radio‐frequency identification (RFID) offers new potential in remote wildlife monitoring to reduce the invasive nature of studies requiring direct contact with study animals. Facilitated by the emergence of new technology, RFID can remotely identify individual animals implanted with passive‐integrated‐transponder (PIT) tags. We aimed to establish and assess a new technique for remote RFID for remotely and noninvasively monitoring a wild population of a semi‐aquatic mammal, the Eurasian beaver (Castor fiber). A fixed reader was installed from June 2018 to July 2019 at beaver lodges within the territories of 8 family‐groups in Vestfold and Telemark, Norway, for 3 nights per lodge, with RFID antennas at lodge entrances. Microchipped beavers were detected when entering or leaving the lodge. The family‐group size recorded using RFID was compared to the known family‐group size based on live capture records and direct observations. The family‐group size recorded using RFID was smaller than the known family‐group size. However, testing suggested that individuals inhabiting a lodge with a fixed reader installed had a high probability of detection (98.44%). Fixed readers are effective where the identification of individuals at a focal point is appropriate, with unique applications for monitoring species with high fidelity to lodges or dens, or species that exhibit central‐place foraging behavior. Research using RFID through fixed PIT tag readers should be given priority for noninvasive beaver population monitoring. Whereas fixed PIT tag readers may not record entire beaver family‐groups, they provide an accurate and efficient alternative to other monitoring techniques. © 2021 The Authors. Wildlife Society Bulletin published by Wiley Periodicals LLC on behalf of The Wildlife Society.

Behavior and detection method influence detection probability of a translocated, endangered amphibian

AbstractAccurate estimates of survival are crucial for many management decisions in translocation programs. Maximizing detection probabilities and reducing sampling biases for released animals can aid in estimates of survival. One important source of sampling bias is an animal’s behavior. For example, individuals that are consistently more exploratory or active may be more likely to be detected visually. Behavioral traits can be related to survival after reintroduction, and because many pre‐release treatments aim to manipulate animal behavior, it is critical to tease apart relationships between behavior and detection probability. Here, we assessed the repeatability (intra‐individual consistency and inter‐individual variation) of behavioral traits for an endangered amphibian, the mountain yellow‐legged frog (Rana muscosa). Because new technological tools offer one potential solution for reducing sampling biases while increasing detection, we also tested whether a long‐range passive integrated transponder (PIT) tag reader could enhance surveys for these individuals after translocation into the wild. After confirming that ex situ bred R. muscosa exhibit repeatable behavioral traits (repeatability = 0.25–0.41) and releasing these frogs (N = 196) into the wild, we conducted post‐release surveys visually and with the long‐range PIT tag reader. Integrating the long‐range reader into surveys improved detection probability four‐fold in comparison to visual surveys alone (~0.09 to ~0.36). Moreover, mark–recapture modeling revealed that tag reader detection probability was not biased toward detecting individuals of specific behavioral types, while visual detection was significantly related to behavioral traits. These results will enable a more accurate understanding of individual differences in post‐release success in translocations. This may be particularly important for amphibian species, which can be difficult to detect and are expected to increasingly be involved in human‐managed breeding and translocation programs due to their vulnerable conservation status.

Validating non-invasive growth measurements on individual Atlantic salmon in sea cages using diode frames

Most Atlantic salmon production takes place in large sea cages where there are limited opportunities to record growth on individual fish. This limits management capabilities for monitoring mean weight and thus total biomass, pellet sizes, feed volumes and the estimation of time until harvest. Furthermore, cause and effect of perturbations and arrested growth cannot be established or interceded on and genetic selection is limited to stocking and harvest measurements. The fusion of passive integrated transponder (PIT) identification and diode frames offers the possibility to noninvasively monitor the growth on thousands of individual fish. However, the accuracy of diode frame measurements for population- and individual level growth and biomass estimation has not been assessed. We stocked over 5000 individually PIT tagged Atlantic salmon post smolts in a net-cage in the sea and monitored growth using a diode frame and PIT tag reader. At the end of the growth period all fish were measured for body length and weight using the intensive gold standard methods of manual recording. At the population level diode frames were highly accurate with a mean difference of 0.002% for length and 4% for weight. Individual level length and weight records were repeatable 0.34 and 0.35, respectively. A single measurement at individual level from diode frames were moderately concordant with the gold standard measures (concordance correlation coefficient (CCC) of 0.52 for length and 0.57 for weight). By exploiting the repeatability and high throughput of diode frame measurements it was possible to increase the number of records per fish to a maximum of 5 resulting in CCC of up to 0.88 for length and 0.81 for weight. Diode frame measurements may hold promise for continuous growth measurements at sea needed in genetic evaluations.

A Serpentine Antenna Configuration for Passive Integrated Transponder Tag Readers Used at Bat Roosts

Abstract We developed a new method for deploying a passive integrated transponder (PIT) with a flexible antenna cable hung as a serpentine curtain at a cave entrance. This fly-through method increased PIT tag detections of nectar-feeding bats (Phyllostomidae) that appeared to pass undetected via other PIT tag antenna configurations.

Postbreeding Habitat Use of the Rare, Pure-Diploid Blue-spotted Salamander (Ambystoma laterale)

Abstract The pure-diploid Blue-spotted Salamander (Ambystoma laterale) is among the rarest amphibians in northeastern North America, and data on its ecology are sparse. We assessed the movement ecology and terrestrial habitat use of A. laterale using radio- and passive integrated transponder (PIT) tag- telemetry. We radio-tracked 22 A. laterale for a median of 54 days (range 6–126 days) in the spring and summer of 2009 and 2010. Using a modified PIT tag reader, we conducted 34 in situ surveys during the spring and summer of 2009 through 2011, resulting in 42 relocations. We detected salamanders at a median straight-line distance of 67 m (range 7–281 m) from their breeding wetland. The life zone (i.e., critical terrestrial habitat), encompassing 95% of observed salamander movements, extended 152 m from the edge of the breeding wetland. Eighteen radio-tracked salamanders migrated to upland forest, three to a wet meadow, and one to a red maple (Acer rubrum) swamp. Salamanders used upland forest and wet meado...

Behavioral Response of Bats to Passive Integrated Transponder Tag Reader Arrays Placed at Cave Entrances

Abstract An increasingly popular mark–recapture method to study the ecology of bats is the use of passive integrated transponder (PIT) tags. Deployment of PIT reader arrays at entrances to caves and mines can yield insight into bat behavior during swarming, winter activity, and emergence. This application has the potential to address questions about bat activity at cave and mine entrances in response to white-nose syndrome or bat seasonal movements; however, no studies have examined the response of bats to these arrays. We describe bat response to placement of PIT tag reader arrays using camcorders and supplemental infrared illuminators at three cave entrances near Bloomington, Indiana, during spring 2006. A random subset of 5-min periods was viewed and bat behavior was classified. Circling represented >70% of all behavior noted for two caves but only represented approximately 30% of behavior at the third cave. Proportions of observed activity that resulted in contacts or landings were consistently low across the three caves (x̄ = 1.34%; range 0.5–3.0%), with most contacts causing bats to simply change course and fly away. Based on our observations, positioning reader PIT tag reader arrays at cave entrances to passively recapture PIT tags does not limit bat movements. However, video monitoring during initial sampling efforts of future projects should be conducted to verify appropriate placement and configuration of PIT tag reader arrays. This research provides data illustrating the lack of significant impact in using PIT tag reader arrays at cave entrances, thereby opening up the potential use of this technology to address issues of bats ecology that cannot be obtained with other marking techniques.

Wildlife Contact Rates at Artificial Feeding Sites in Texas

Given the popularity of feeding white-tailed deer (Odocoileus virginianus) in Texas and the increasing amount of corn that is distributed, more information is needed on the impacts of this activity on non-target wildlife. Our objectives were to report visitation, intra- and interspecific contact, and contact rates of wildlife at artificial feeding sites in Texas. Our study was conducted at three sites in Kleberg and Nueces counties, Texas. We trapped animals from February to April and August to September, 2009 and marked animals with passive integrated transponder (PIT) tags. At each site and season, we placed one feeder system containing a PIT tag reader within 600 m of trap locations. Readers detected PIT tags from a distance of 25 cm. We determined a contact event to occur when two different PIT tags were detected by feeder systems within 5 s. We recorded 62,719 passes by raccoons (Procyon lotor), 103,512 passes by collared peccaries (Pecari tajacu), 2,923 passes by feral swine (Sus scrofa), 1,336 passes by fox squirrels (Sciurus niger), and no passes by opossums (Didelphis virginiana) at feeder systems. For site-season combinations in which contact events occurred, we found intraspecific contact rates (contacts per day) for raccoons, collared peccaries, and feral swine to be 0.81-124.77, 0.69-38.08, and 0.0-0.66, respectively. Throughout our study we distributed ~2,625 kg of whole kernel corn, which resulted in 6,351 contact events between marked wildlife (2.4 contacts per kg of corn). If 136 million kg of corn is distributed in Texas annually, we would expect >5.2 billion unnatural contact events between wildlife would result from this activity each year in Texas. Consequently, we do not believe that it is wise for natural resource managers to maintain artificial feeding sites for white-tailed deer or other wildlife due to pathogen transmission risks.

Recruitment in a Colorado population of big brown bats: breeding probabilities, litter size, and first-year survival

We used mark–recapture estimation techniques and radiography to test hypotheses about 3 important aspects of recruitment in big brown bats (Eptesicus fuscus) in Fort Collins, Colorado: adult breeding probabilities, litter size, and 1st-year survival of young. We marked 2,968 females with passive integrated transponder (PIT) tags at multiple sites during 2001–2005 and based our assessments on direct recaptures (breeding probabilities) and passive detection with automated PIT tag readers (1st-year survival). We interpreted our data in relation to hypotheses regarding demographic influences of bat age, roost, and effects of years with unusual environmental conditions: extreme drought (2002) and arrival of a West Nile virus epizootic (2003). Conditional breeding probabilities at 6 roosts sampled in 2002–2005 were estimated as 0.64 (95% confidence interval [95% CI] 5 0.53–0.73) in 1-year-old females, but were consistently high (95% CI 5 0.94–0.96) and did not vary by roost, year, or prior year breeding status in older adults. Mean litter size was 1.11 (95% CI 5 1.05–1.17), based on examination of 112 pregnant females by radiography. Litter size was not higher in older or larger females and was similar to results of other studies in western North America despite wide variation in latitude. First-year survival was estimated as 0.67 (95% CI 5 0.61–0.73) for weaned females at 5 maternity roosts over 5 consecutive years, was lower than adult survival (0.79; 95% CI 5 0.77–0.81), and varied by roost. Based on model selection criteria, strong evidence exists for complex roost and year effects on 1st-year survival. Firstyear survival was lowest in bats born during the drought year. Juvenile females that did not return to roosts as 1year-olds had lower body condition indices in late summer of their natal year than those known to survive. DOI: 10.1644/08-MAMM-A-295.1.

The use of PIT telemetry to study movements of ammocoetes and metamorphosing sea lampreys in river beds

Passive integrated transponder (PIT) tags were surgically implanted in 118 sea lamprey Petromyzon marinus ammocoetes which were left to recover in the laboratory for 2 months. During this period 55 individuals started to metamorphose. In the late summer of 2002 the tagged animals were released in a small tributary of the River Mondego, Portugal, and were regularly monitored for a period of 2 months using a portable PIT tag reader. The distribution of the released animals changed from an initial uniform pattern to a random distribution, and then to an aggregated pattern. At the end of the first week 60% of the tagged sea lampreys had already left the study area, indicating their dynamic behaviour. Ammocoetes were more active than metamorphosing sea lampreys, and downstream movements were more frequent when compared to the upstream ones, which were usually a short distance. In order to determine the influence of the dark‐light cycle in the diel activity rhythms, 10 tagged sea lamprey ammocoetes were released in a tank (2000 l capacity) and their position monitored twice a day, for a period of 1 month. Ammocoetes locomotor activity appeared to be conditioned by circadian rhythms, and they were particularly active during darkness.