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Copyright of Journal of Field Ornithology is the property of Resilience Alliance and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Autonomous recording units (ARUs) paired with signal classification software can be used to detect species‐specific calls, making them useful for evaluating patterns in avian occurrence and activity. However, classification of target signals is not always reliable and may be especially challenging for species that vocalize infrequently. We assessed the use of ARUs to identify and monitor habitat for a cryptic and federally threatened distinct population segment, the western yellow‐billed cuckoo (Coccyzus americanus) in mountainous xeroriparian drainages. Using Kaleidoscope Pro, we developed a call‐classifier and processed acoustic data collected in sites also surveyed using traditional human‐observer methods, applying the same spatial and temporal detection criteria to estimate breeding territories for each method. The classifier detected a total of 4,061 true positive calls at 4 sites, had an overall precision score of 0.07, recall score of 0.09, and F‐score (beta = 1) of 0.08, indicating high false positive and false negative classification rates. Our results were, however, consistent with other ARU studies of rare and cryptic species and ARUs estimated occupancy as effectively as human surveys with as little as 2 hours of daily recording. Total detections varied among sites, likely due to differences in cuckoo population densities and the interaction between topography and ARU detection space. Our results suggest that despite performance shortcomings of call‐classifiers, ARUs can be effective for monitoring cuckoos, with potential for providing higher resolution temporal and spatial information on activity and habitat use and may be particularly effective in remote locations where cuckoos often occur. [ABSTRACT FROM AUTHOR]

Potentially fatal wildlife diseases like rabies are of increasing concern, due to human effects on the environment that could alter wildlife behavior and population dynamics in ways that increase disease prevalence. Wildlife population abundance is a key factor, affecting both disease outbreak and rate of disease spread, and understanding how population abundance changes across landscapes is crucial for developing predictive models to control and manage wildlife diseases. We investigated how urbanization in Flagstaff, AZ influenced skunk population abundance by simultaneously trapping 6 pairs of suburban and wildland study sites for 200 trap-nights between June and September 2011. The number of unique skunks captured at the 6 suburban locations ranged from 3-14 (mean = 6.5) while the number trapped at the 6 wildland sites ranged from 0-2 (mean = 0.5). We also reviewed data gathered as part of the trap-vaccinate-release (TVR) program carried out from 2004-2010 by USDA APHIS Wildlife Services to estimate population sizes and the percentage of the population vaccinated. Our estimates of the percentage of the population vaccinated in any one year ranged from 11%-23%, below percentages reported in the literature as necessary to prevent disease spread. Overall, these data indicate that the potential for disease spread was greatest within the suburban matrix and relatively low in surrounding wildlands and that intensified annual TVR programs would be necessary to maintain high enough percentages of immunized animals to achieve effective herd immunity.

On the California Channel Islands, wildlife researchers have hypothesized that the island fox (Urocyon littoralis) competes with the smaller-bodied island spotted skunk (Spilogale gracilis amphiala). Recent declines in spotted skunk captures have raised concerns about the status of the spotted skunk population on Santa Cruz Island and the potential role of foxes in the decline. From 2018 to 2019, we used global positioning system and very-high-frequency radio collars to assess patterns of space use by foxes and spotted skunks and deployed remote cameras to determine the potential for interaction between the two species at spotted skunk den sites. Spotted skunk home ranges were approximately five times larger than previously reported (range = 55–299 ha), and temporal patterns of space use differed between spotted skunks and foxes, with spotted skunks utilizing only 32% of their 6-month home range during a week, while foxes moved more widely over short time periods, covering 60% of their seasonal home range during 1 week. In spite of overall larger seasonal home ranges, the number of vegetation types used by spotted skunks (mean = 4) was smaller than that used by foxes (mean = 7) living in the same area, consistent with the narrow niche hypothesized for spotted skunks. More broadly, selection for vegetation types varied among individuals, within species, and across locations on the island. Based on camera trapping at spotted skunk den sites, we found a positive relationship between spotted skunk visitation rate and slope at den sites but no relationship with vegetation cover, suggesting more heavily used dens were in areas of steeper slope. Photographic evidence of a fox attempting to dig an adult spotted skunk from its den suggested predation at den sites could be a factor in spotted skunk mortality. En las Islas del Canal de California, el zorro isleño (Urocyon littoralis) ha se ha planteado la hipótesis de que compite con el zorillo manchada de la isla (Spilogale gracilis amphiala) de cuerpo más pequeño. Las recientes disminuciones en las capturas de zorrillos manchados han suscitado preocupaciones sobre el estado de la población de zorrillos manchados en la isla Santa Cruz y el papel potencial de los zorros en la disminución. De 2018 a 2019, utilizamos collares de radio GPS y VHF para evaluar los patrones de uso del espacio por los zorros y zorrillos moteados y desplegamos cámaras remotas para determinar el potencial de interacción entre las dos especies en los sitios de guaridas de zorrillos moteados. Los rangos de hogar estacionales (HR) de zorrillos manchados eran aproximadamente cinco veces más grandes de lo que se informó anteriormente, y los patrones temporales de uso del espacio diferían entre los zorrillos manchados y los zorros, con los zorrillos manchados utilizando solo el 32% de su HR de seis meses durante una semana, mientras que los zorros se movían más ampliamente en períodos de tiempo cortos, cubriendo el 60% de su FC estacional durante una semana. A pesar de los rangos de hogar estacionales más amplios en general, el número de tipos de vegetación utilizados por los zorrillos manchados fue menor que el utilizado por los zorros que viven en la misma área, en consonancia con el nicho estrecho hipotético para los zorrillos manchados. En términos más generales, la selección de los tipos de vegetación varió entre los individuos, dentro de las especies y entre los lugares de la isla. Basándonos en la captura de cámaras en los sitios de guaridas de zorrillos manchados, encontramos una relación positiva entre la tasa de visitas de zorrillos manchados y la pendiente en los sitios de guaridas, pero ninguna relación con la cubierta vegetal, lo que sugiere que las guaridas más utilizadas estaban en áreas de pendientes más pronunciadas. La evidencia fotográfica de un zorro que intenta sacar una mofeta moteada adulta de su guarida sugiere que la depredación en los sitios de guarida podría ser un factor en la mortalidad de la mofeta manchada. [ABSTRACT FROM AUTHOR]

We examined the potential for urban water sources, specifically golf course ponds, to act as centers for rabies transmission from bats to mesocarnivores in the arid southwestern United States where surface water is often limited. Because residential housing can act as den and roost sites for both mesocarnivores and bats, we also examined the effect of housing density around water sources on activity. Using ultrasonic acoustic recorders to assess bat activity and camera traps to estimate mesocarnivore activity, we compared 14 pairs of wet and dry locations over two years by surveying twice during the summer, once prior to summer monsoons and once during the monsoon season, when surface waters were more available. Number of calls for all bat species combined were greater at wet sites compared to dry sites and calls of two bat species often associated with rabies, big brown bat (Eptesicus fuscus) and silver-haired bat (Lasionycteris noctivagans), were recorded more at wet sites than dry sites in the monsoon season. In both years, raccoons (Procyon lotor) were photographed more often at wet sites while striped skunks (Mephitis mephitis) and gray foxes (Urocyon cinereoargenteus) were less likely to be detected at wet sites. Bat, fox and raccoon activity was not associated with housing density while striped skunks showed a positive correlation. Finally, we examined potential for contact between mesocarnivores and big brown bats, a species implicated in cross-species rabies transmission in our area, by combining call activity of this bat species and photo detections of mesocarnivores during individual hours of the night into a Potential Contact Index (PCI) and found no significant effect of season (pre-monsoon vs. monsoon), species, or treatment (dry versus wet) but did find a significant species by treatment interaction, with raccoon PCI 3–30 times higher at wet sites and no effect on the other two mesocarnivores' PCI. Overall, we found higher activity of bats at urban waters could increase potential for cross-species transmission of rabies from bats to raccoons but not for gray foxes and striped skunks. [ABSTRACT FROM AUTHOR]

The effects of traffic volume and vehicle type on elk use of wildlife underpasses in Arizona are studied. It is found that the wildlife underpasses are effective in preventing elk population fragmentation due to high traffic volume on highways.

A study examined whether traffic volume affected elk distribution and highway crossings in Arizona. Findings confirmed the effect and suggested that placing wildlife crossing structures near meadows could allow elk to pass safely and thus avoid elk-vehicle collisions.

Although polygyny can potentially increase male reproductive success, the benefits of this strategy could be offset by losses to extra-pair paternity or reduced offspring survival. We developed microsatellite markers to assess the influence of extra-pair offspring (EPO) on reproductive success and paternity in monogamous and polygynous pairs of the facultatively polygynous Southwestern Willow Flycatcher (Empidonax traillii extimus). Based on genotypes of 140 offspring from 56 clutches over six years, 14% of nestlings in our study population were extra-pair offspring, with 23% of all successful nests containing at least one EPO. We found that polygynous males produced 2.11 [+ or -] 0.35 offspring per season, compared to 1.15 [+ or -] 0.18 for monogamous males. This increased reproductive success was due primarily to the increased number of nests of polygynous males, as the number of offspring per pair did not differ between monogamous and polygynous males. Twenty of the 140 genotyped nestlings were extrapair offspring. Sires could be assigned to 16 of these; one polygynous male sired two EPO in one nest, two monogamous males sired eight EPO in two nests, and four nonterritorial males sired six EPO in four nests. Overall, these results indicate that in this population, females of polygynous males did not raise a disproportionate number of EPO as a result of the polygynous mating strategy of their mate, and that both territorial and nonterritorial males sired EPO. Key words: extra-pair offspring, microsatellite, polygyny, reproductive success, Willow Flycatcher. A pesar de que la poliginia puede potencialmente aumentar el exito reproductivo de los machos, el beneficio de esta estrategia puede ser contrarestado por perdidas ocasionadas por la paternidad extra pareja o pot la reduccion de la supervivencia de la progenie. Desarrollamos marcadores microsatelitales para determinar la influencia de la progenie extra pareja (PEP) sobre el exito reproductivo y la paternidad en parejas monogamas y poliginas de la especie facultativamente poligina Empidonax traillii extimus. Con base en genotipos de 140 crias provenientes de 56 nidadas en seis anos, determinamos que el 14% de los polluelos en nuestra poblacion de estudio fueron PEP y que el 23% de todos los nidos exitosos contuvo por lo menos una PEP. Encontramos que los machos poliginos produjeron 2.11 [+ or -] 0.35 crias por estacion, en comparacion con 1.15 [+ or -] 0.18 crias producidas por machos monogamos. Este exito reproductivo mayor se debio principalmente al mayor numero de nidos de los machos poliginos, ya que el numero de crias por pareja no difirio entre machos monogamos y poliginos. De los 140 polluelos analizados genotipicamente, 20 fueron PEP. Los padres progenitores pudieron ser identificados para 16 de estos polluelos. Un macho poligino engendro dos PEP en un nido, dos machos monogamos engendraron ocho PEP en dos nidos y cuatro machos no territoriales engendraron seis PEP en cuatro nidos. En general, estos resultados indican que en esta poblacion las hembras de machos poliginos no criaron un numero desproporcionado de PEP como resultado de la estrategia de apareamiento poligina de sus parejas y que tanto los machos territoriales como los no territoriales engendraron PEP.