Movement patterns and space use of the first giant anteater (Myrmecophaga tridactyla) monitored in São Paulo State,Brazil

This study analyzes a giant anteater’s (Myrmecophaga tridactyla) movement patterns and space use in São Paulo, Brazil. It is the first study to track a giant anteater with Iridium-GPS. The anteater traveled an average distance of 1326 m day^–1 with an average speed of 1.04 m min^–1. Home range by Kernel was 2.46 km² while the core area was 0.75 km², and estimates by Brownian bridge and minimum convex polygon were also provided. The anteater used shrub savanna, open savanna, and water habitats more than expected. Monitoring ended just after 10 days when the female giant anteater’s GPS was found on an illegal trail.     

Externally attached radio transmitters do not affect the parental care behaviour of rock bass

Turning, pectoral fin and caudal fin rates and time spent on the nest of male rock bass Ambloplites rupestris , engaged in parental care, were not affected after the attachment of external radio transmitters. Reproductive success was similar between treatment and control fish. Micro external radio transmitters can be used on small fishes for studying parental care duration and post-care movement without altering their behaviour.     

Can We Accurately Characterize Wildlife Resource Use When Telemetry Data Are Imprecise?

ABSTRACT Telemetry data have been widely used to quantify wildlife habitat relationships despite the fact that these data are inherently imprecise. All telemetry data have positional error, and failure to account for that error can lead to incorrect predictions of wildlife resource use. Several techniques have been used to account for positional error in wildlife studies. These techniques have been described in the literature, but their ability to accurately characterize wildlife resource use has never been tested. We evaluated the performance of techniques commonly used for incorporating telemetry error into studies of wildlife resource use. Our evaluation was based on imprecise telemetry data (mean telemetry error = 174 m, SD = 130 m) typical of field-based studies. We tested 5 techniques in 10 virtual environments and in one real-world environment for categorical (i.e., habitat types) and continuous (i.e., distances or elevations) rasters. Technique accuracy varied by patch size for the categorical rasters, with higher accuracy as patch size increased. At the smallest patch size (1 ha), the technique that ignores error performed best on categorical data (0.31 and 0.30 accuracy for virtual and real data, respectively); however, as patch size increased the bivariate-weighted technique performed better (0.56 accuracy at patch sizes >31 ha) and achieved complete accuracy (i.e., 1.00 accuracy) at smaller patch sizes (472 ha and 1,522 ha for virtual and real data, respectively) than any other technique. We quantified the accuracy of the continuous covariates using the mean absolute difference (MAD) in covariate value between true and estimated locations. We found that average MAD varied between 104 m (ignore telemetry error) and 140 m (rescale the covariate data) for our continuous covariate surfaces across virtual and real data sets. Techniques that rescale continuous covariate data or use a zonal mean on values within a telemetry error polygon were significantly less accurate than other techniques. Although the technique that ignored telemetry error performed best on categorical rasters with smaller average patch sizes (i.e., ≤31 ha) and on continuous rasters in our study, accuracy was so low that the utility of using point-based approaches for quantifying resource use is questionable when telemetry data are imprecise, particularly for small-patch habitat relationships.     

Diurnal space use and nocturnal roost‐site selection by male Cerulean Warblers during the breeding season

Detailed information about space use during the breeding season is limited for most Nearctic‐Neotropical migratory species of songbirds because of their small size and often cryptic behaviors. We monitored male Cerulean Warblers (Setophaga cerulea), a species of conservation concern, using radio‐telemetry during the 2006–2008 breeding seasons in northern Alabama to better understand their space use and habitat selection. We estimated diurnal home range and core areas using information theoretic criteria, located nocturnal roost sites, and related day and evening locations to surrounding landscape habitat, including features representative of canopy disturbances. Mean home range size was 6.7 ha (N = 10), and home ranges included an average of at least 2 core areas encompassing 0.7 ha. We located 53 nocturnal roost sites that were an average 159.0 m from the center of the nearest core area. More than one‐third (36.6%) of roost sites were located outside the diurnal home ranges of male Cerulean Warblers; only 13.6% were located in core areas. Males in our study moved much farther than reported in previous studies, with some singing in areas > 300 m from previously used song perches, a behavior suggesting pursuit of extra‐pair copulations. Cerulean Warblers in our study preferentially selected a heavily forested landscape composed of mesic, floodplain bottomlands with little man‐made disturbance. Within their home ranges, diurnal locations of males in core areas were located significantly closer to a creek than locations outside of core areas. Our results suggest that male Cerulean Warblers require much larger areas than previously reported and underscore the importance of a predominately forested landscape in their habitat selection process. Although edge habitats appeared to influence space use by male Cerulean Warblers in our study, the extent to which this is an essential requirement is unclear. Our results and those of previous studies suggest that specific habitat requirements of this species can vary at the local scale throughout its breeding range.     

Bachman's Sparrows at the northern periphery of their range: home range size and microhabitat selection

Populations of Bachman's Sparrows (Peucaea aestivalis) have declined range‐wide since the late 1960s. Populations at the periphery of their range have exhibited some of the steepest declines, and these sparrows are now rare or extirpated over much of the northern extent of their historical range. To better understand the spatial ecology of Bachman's Sparrows in this region of decline, we examined microhabitat selection and determined the home range sizes of radio‐tagged male Bachman's Sparrows (N = 37) in the Coastal Plain of North Carolina in 2014 and 2015. From April to July, we located males 1–2 times daily for 5–6 d per week. We measured vegetation structure in home ranges using 5‐m‐radius plots centered on a subset of 10 randomly selected telemetry locations as well as in available unused locations 50 m and in a random direction from each telemetry location. Mean size of home ranges (7.9 ha) was larger than estimates reported in most previous studies, with differences among studies possibly due, at least in part, to differences in the characteristics of habitats where studies were conducted. The home ranges of Bachman's Sparrows in our study had greater densities of woody and dead vegetation than unused areas. Although generally considered detrimental to the presence of Bachman's Sparrows, the presence of some woody vegetation in frequently burned (i.e., ≤ 3‐yr return interval) longleaf pine (Pinus palustris) communities like those in our study may be important in providing song perches for males and cover from attacking predators. Bachman's Sparrows in our study showed clear selection for several vegetation characteristics linked to frequent fire. Management strategies that approximate historical fire regimes in longleaf pine ecosystems should continue to be promoted as essential tools for the conservation of Bachman's Sparrows.     

Improving our understanding of demographic monitoring: avian breeding productivity in a tropical dry forest

The ratio of juvenile to adult birds in mist‐net samples is used to monitor avian productivity, but whether it is a “true” estimate of per capita productivity or an index proportional to productivity depends on whether capture probability is not age‐dependent (true estimate) or age difference in capture probability is consistent among years (index). Better understanding of the processes affecting age‐ and year‐specific capture probabilities is needed to advance the application of constant‐effort mist‐netting for monitoring and conservation, particularly in many tropical settings where capture rates are often low. We ranked members of the avian community by capture frequencies, determined if temporary emigration influenced the availability of birds to be captured, and assessed the distribution of birds relative to mist‐nets and the parity between capture‐based productivity estimates and number of fledglings in nest plots in a tropical dry forest in Puerto Rico in 2009 and 2010. Few captures characterized the community of 25 resident species and, when estimable, capture probabilities were low, particularly for juveniles (typically < 0.1). Negative trends in capture probability, temporary emigration, and the distribution of birds suggest that avoidance of mist‐nets influenced capture rates in our study. Increasing mist‐net coverage or moving mist‐nets between sampling periods could increase capture rates. The number of fledglings observed in nest plots (25 ha/plot) did not correlate well with capture‐derived estimates (20 ha/net stations), suggesting the presence of immigrants or failure to find all nests. Our results suggest that indices of breeding productivity from mist‐netting data may track temporal changes in productivity, but such data likely do not reflect “true” productivity in most cases unless age‐specific differences in capture probability are incorporated into estimates. Pilot studies should be conducted to evaluate capture rates and the spatial extent sampled by mist‐nets to improve sampling design and inferences before informing decisions.     

DIFFERENTIAL MOVEMENTS BY HARBOR SEAL PUPS IN CONTRASTING ALASKA ENVIRONMENTS

Movement patterns of Alaska harbor seal pups were studied using satellite telemetry during 1997–2000. Mean tracking duration was 277.3 d (SD = 105.8) for Tugidak Island pups ( n = 26) and 171.2 d (108.3) for Prince William Sound (PWS) pups ( n = 27). Movements were similar for males and females and were largely restricted to the continental shelf. Multiple return trips of > 75 km from the natal area and up to ∼3 wk duration were most common, followed by movements restricted to <25 km from the natal area; one way movements from the natal site were rare. Distances moved and home range sizes remained relatively stable or increased gradually from July through winter, then decreased markedly through spring. Monthly movements (maximum distance from tagging location, mean distance from haul-outs to at-sea locations, and home range size) were significantly greater for Tugidak vs . PWS pups. Six of seven pups from each region that traveled farthest and were tracked the longest had returned to their tagging site when their last location was recorded, indicating philopatry or limited dispersal during their first year of life. Seal pups exhibited similar movement patterns in the distinct habitats of the two regions, but differed in the spatial extent of their movements.