Activity Budgets Derived From Time-Depth Recorders in a Diving Mammal

Abstract: We describe a method to convert continuously collected time-depth data from archival time-depth recorders (TDRs) into activity budgets for a benthic-foraging marine mammal. We used data from 14 TDRs to estimate activity-specific time budgets in sea otters (Enhydra lutris) residing near Cross Sound, southeast Alaska, USA. From the TDRs we constructed a continuous record of behavior for each individual over 39-46 days during summer of 1999. Behaviors were classified as foraging (diving to the bottom), other diving (traveling, grooming, interacting), and nondiving (assumed resting). The overall average activity budget (proportion of 24-hr/d) was 0.37 foraging (8.9 hr/d), 0.11 in other diving (2.6 hr/d), and 0.52 nondiving time (12.5 hr/d). We detected significant differences in activity budgets among individuals and between groups within our sample. Historically, the sea otter population in our study area had been expanding and sequentially reoccupying vacant habitat since their reintroduction to the area in the 1960s, and our study animals resided in 2 adjacent yet distinct locations. Males (n = 5) and individuals residing in recently occupied habitat (n = 4) spent 0.28-0.30 of their time foraging (6.7-7.2 hr/d), 0.17-0.18 of their time in other diving behaviors (4.1-4.3 hr/d), and 0.53-0.54 of their time resting (12.7-13.0 hr/d). In contrast, females (n = 9) and individuals residing in longer occupied habitat (n = 10) spent 0.40 of their time foraging (9.6 hr/d), 0.08-0.09 of their time in other diving behaviors (1.9-2.2 hr/d), and 0.51-0.52 of their time resting (12.2-12.5 hr/d). Consistent with these differences, sea otters residing in more recently occupied habitat captured more and larger clams (Saxidomus spp., Protothaca spp., Macoma spp., Mya spp., Clinocardium spp.) and other prey, and intertidal clams were more abundant and larger in this area. We found that TDRs provided data useful for measuring activity time budgets and behavior patterns in a diving mammal over long and continuous time periods. Fortuitous contrasts in time budgets between areas where our study animals resided suggest that activity time budgets estimated from TDRs may be a sensitive indicator of population status, particularly in relation to prey availability.     

Factors influencing Willow Tit Poecile montanus site occupancy: a comparison of abandoned and occupied woods

The British Willow Tit Poecile montanus kleinschmidti underwent a decline of 85% between 1970 and 2003. The cause of this decline is unknown. However, several hypotheses have been put forward to account for it: competition from other tit species, predation by Great Spotted Woodpeckers Dendrocopos major and habitat change. In order to test these, woods that are currently occupied by Willow Tits were paired with woods (within 50 km) that had been abandoned by Willow Tits five or more years previously. Point counts for other tit species (potential competitors) and woodpecker species (potential predators) were carried out at ten evenly spaced points throughout each wood. Habitat variables were collected within a 50-m radius of where a Willow Tit was located (in the occupied woods) or where maps showed a Willow Tit had been located (for abandoned woods). No evidence was found for differences in numbers of potential competitor or potential predator species in abandoned and occupied woods. Soil water content was found to be higher at occupied sites. No other habitat features differed between the two categories of site. The drying up of British woods could therefore be implicated in the Willow Tit decline and this warrants further investigation.     

Technique,Safety, and Efficacy of Intra-Abdominal Transmitters in Nine-Banded Armadillos

ABSTRACT The future management of nine-banded armadillos (Dasypus novemcinctus) requires solid space-use and activity data, which are currently lacking and which radiotelemetry can provide. External radiotransmitters have not been successful applied with this species. To make recommendations for intra-abdominal radiotransmitter placement in nine-banded armadillos, we 1) evaluated 4 different anesthetic protocols for safety, efficiency, and cost-effectiveness; 2) evaluated a surgical technique for the intra-abdominal placement of radiotransmitters that addresses problems described in previous studies; and 3) evaluated the physiologic and behavioral effects of such a technique. We captured and surgically implanted 37 nine-banded armadillos using either butorphanol and isoflurane, ketamine alone, ketamine and xylazine, or a combination of butorphanol, ketamine, and medetomidine for anesthesia. We recovered and necropsied armadillos after the completion of the study. The objective and subjective assessment of butorphanol, ketamine, and medetomidine combination protocol, followed by reversal of the anesthesia with atipamezole, showed that it was the best overall anesthetic protocol for field use, providing both a smooth induction and fast recovery. We evaluated the fate and effects of radiotransmitters on 13 recovered animals at the end of the study and found no adverse effects. We recommend the implantation of radiotransmitters that are allowed to free-float within the abdominal cavity and specifically emphasize the need for strict aseptic technique. Wildlife managers and wildlife veterinarians aiming to implant nine-banded armadillos with radiotransmitters will benefit from using the recommended anesthetic protocol and surgical technique in future studies.     

Size Effects on the Uptake of Particles by Populations of Tetrahymena pyriformis Cells

Flow cytometry has been used to make direct measurements of rates of uptake of latex microspheres from dilute, monodisperse suspensions by Tetrahymena pyriformis. Measurements were made for five different sizes of microspheres, ranging from 1.09 to 6.17 μm diameter. Fractions of cells in the population that did not ingest the microspheres offered were also determined. In addition, the size distributions, as indicated by the forward angle light scattering intensity which is measured by the instrument, were determined for the whole population and for the subpopulations of cells that did and did not ingest the particles, for each particle size used. It was found that the fraction of cells that did not ingest the particles was small and independent of particle size when this was less than about 2.7 μm, but increased with particle size when particle size was increased above this value. The so-called maximum clearance rate, which can be calculated from the data, was found to increase monotonically with particle size if it were based only on those cells which actually ingested the particles offered. However, a plot of maximum clearance rate vs. particle size exhibited a maximum if the clearance rate were based on all cells present in the population.     

Winter Forage Selection in White-Tailed Deer at High Density: Balsam Fir is the Best of a Bad Choice

Abstract: We assessed winter forage selection by white-tailed deer (Odocoileus virginianus) on Anticosti Island, Quebec, Canada, using cafeteria-feeding trials. Winter habitat on Anticosti is degraded and free-ranging deer at high densities consume 70% balsam fir (Abies balsamea) and 20% white spruce (Picea glauca), even though spruce is much more available than fir. Deer ate 89.9% balsam fir and 10.1% white spruce when the availability of both trees was equal. Deer did not eat shredded twigs more than intact twigs. Fiber content and condensed tannins were greater in white spruce than in balsam fir. Deer preference for fir was not based on texture but, more likely, on plant constituents, so we concluded that deer will nearly eliminate fir before they use any significant amount of white spruce. Management actions, therefore, need to be undertaken to enhance balsam fir regeneration.     

DIRECT DETECTION OF ESCHERICHIA COLI 0157:H7 IN UNPASTEURIZED APPLE JUICE WITH AN EVANESCENT WAVE BIOSENSOR

An evanescent wave biosensor was used to detect Escherichia coli O157:H7 in unpasteurized apple juice. Light is launched from a 635 nm laser diode into silica or polystyrene optical waveguides, generating an evanescent field which extends from the waveguide surface. Fluorescent molecules within the evanescent field are excited resulting in an emission signal that the biosensor then detects and quantifies. A sandwich immunoassay was performed on the waveguides using cyanine 5 dye-labeled anti-E. coli O157:H7 antibodies for generation of the specific fluorescent signal. The lower limit of detection was between 6.0 × 10² and 6.0 × 10⁴ CFU/mL with silica waveguides and between 3.2 × 10⁴ and 3.2 × 10⁴ CFU/mL using polystyrene waveguides. One-hundred percent correct identification of true positive samples occurred at 6.0 × 10⁴ and 3.2 × 10⁴ CFU/mL for silica and polystyrene waveguides, respectively. Signals from a variety of non-E. coli O157 bacteria, including closely related enterotoxigenic strains of E. coli at concentrations of ˜ 10⁶ CFU/mL, were below the limits of detection. Assays were conducted in near real-time with results obtained within 15 min of sample processing.     

Delineation of the European Armillaria species based on the sequences of the internal transcribed spacer (ITS) of ribosomal DNA

Variation within the internal transcribed spacer (ITS) of the ribosomal RNA gene of 15 isolates representing seven European Armillaria species, was examined by sequencing of the PCR-amplified products. The analysis of an 744-bp region showed that the 5.8S gene appeared to be highly conserved in the 15 isolates and in other Basidiomycetes and Ascomycetes, whereas ITS1 and especially ITS2 spacers exhibited polymorphisms due to base substitutions, insertions or deletions of up to eight nucleotides. An initial dendrogram for the full sequence was drawn using cluster analysis (UPGMA), and a tree was constructed using the maximum parsimony method. Both methods indicated that the isolates could be divided into four major groups. One group, consisting of A. ectypa , was distinct from all the other species. Examination of the other groups indicated that A. tabescens and A. mellea were in a separated cluster, with a significant variation between the two isolates of the latter species. A. gallica and A. cepistipes constituted another closely related group distinguishable from A. ostoyae and A. borealis , these latter two species exhibiting the highest similarity. The results are consistent with, and discussed in regard to, the relationships estimated previously by pairing tests, morphological and physiological comparisons, as well as by restriction fragment length polymorphism of the rDNA.