Search

Abstract Plastic pollution is distributed patchily around the world’s oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species.

Abstract Prey selection is a fundamental aspect of ecology that drives evolution and community structure, yet the impact of intraspecific variation on the selection for prey size remains largely unaccounted for in ecological theory. Here, we explored puma (Puma concolor) prey selection across six study sites in North and South America. Our results highlighted the strong influence of season and prey availability on puma prey selection, and the smaller influence of puma age. Pumas in all sites selected smaller prey in warmer seasons following the ungulate birth pulse. Our top models included interaction terms between sex and age, suggesting that males more than females select larger prey as they age, which may reflect experiential learning. When accounting for variable sampling across pumas in our six sites, male and female pumas killed prey of equivalent size, even though males are larger than females, challenging assumptions about this species. Nevertheless, pumas in different study sites selected prey of different sizes, emphasizing that the optimal prey size for pumas is likely context‐dependent and affected by prey availability. The mean prey weight across all sites averaged 1.18 times mean puma weight, which was less than predicted as the optimal prey size by energetics and ecological theory (optimal prey = 1.45 puma weight). Our results help refine our understanding of optimal prey for pumas and other solitary carnivores, as well as corroborate recent research emphasizing that carnivore prey selection is impacted not just by energetics but by the effects of diverse ecology.

Abstract Using a dataset of 591 capture events between 2001–2019 in California, USA, we examined the impact of capture methods and immobilization drugs on mountain lion (Puma concolor) welfare. The 3 methods used to capture mountain lions were cage traps, trained hounds, and cable restraints. The drugs used to immobilize mountain lions were either tiletamine/zolazepam (Telazol®), ketamine/medetomidine, or ketamine/xylazine. Mortality occurred in 1.4% of captures, with only one mortality out of 310 captures occurring since 2012. We used a logistic regression framework to compare morbidity and vital parameters of mountain lions among the different capture methods and immobilization drugs used. Vomiting (a risk factor for developing aspiration pneumonia) was the most common severe risk factor associated with cage trapping and was only seen with the use of ketamine/medetomidine or ketamine/xylazine. Morbidity scores were not well predicted by any of the variables we accounted for. Animals immobilized with Telazol® were more likely to experience abnormal heart and respiratory rates, as well as high body temperatures, than those immobilized with the other two combinations. Although there are risks associated with each of the capture methods and drug combinations commonly used in mountain lion captures in California, our analyses demonstrated they are all relatively safe when following appropriate animal welfare practices. Our analyses suggested that unaccounted for factors are equally or more important in explaining injury and physiological abnormality rates, and we urge that agencies train personnel in best practices and conservative decision‐making in order to assure that the welfare of the animal takes precedence over collaring. We suggest training on how to choose between several capture techniques, immobilization drugs and monitoring methods and how to reduce both detrimental effects to mountain lions and danger to humans.

Abstract Identifying mechanisms of population change is fundamental for conserving small and declining populations and determining effective management strategies. Few studies, however, have measured the demographic components of population change for small populations of mammals (

Abstract Mortality site investigations of telemetered wildlife are important for cause‐specific survival analyses and understanding underlying causes of observed population dynamics. Yet, eroding ecoliteracy and a lack of quality control in data collection can lead researchers to make incorrect conclusions, which may negatively impact management decisions for wildlife populations. We reviewed a random sample of 50 peer‐reviewed studies published between 2000 and 2019 on survival and cause‐specific mortality of ungulates monitored with telemetry devices. This concise review revealed extensive variation in reporting of field procedures, with many studies omitting critical information for the cause of mortality inference. Field protocols used to investigate mortality sites and ascertain the cause of mortality are often minimally described and frequently fail to address how investigators dealt with uncertainty. We outline a step‐by‐step procedure for mortality site investigations of telemetered ungulates, including evidence that should be documented in the field. Specifically, we highlight data that can be useful to differentiate predation from scavenging and more conclusively identify the predator species that killed the ungulate. We also outline how uncertainty in identifying the cause of mortality could be acknowledged and reported. We demonstrate the importance of rigorous protocols and prompt site investigations using data from our 5‐year study on survival and cause‐specific mortality of telemetered mule deer (Odocoileus hemionus) in northern California. Over the course of our study, we visited mortality sites of neonates (n = 91) and adults (n = 23) to ascertain the cause of mortality. Rapid site visitations significantly improved the successful identification of the cause of mortality and confidence levels for neonates. We discuss the need for rigorous and standardized protocols that include measures of confidence for mortality site investigations. We invite reviewers and journal editors to encourage authors to provide supportive information associated with the identification of causes of mortality, including uncertainty.

Abstract Artificial light at night (ALAN) is considered a major threat to biodiversity, yet impacts of offshore ALAN on seabirds remain poorly understood. Particularly understudied are deck strikes (collisions of seabirds with vessels due to ALAN‐induced disorientation). To infer deck strike risks to the critically endangered Whenua Hou Diving‐petrel (Pelecanoides whenuahouensis; WHDP), we estimated nightly vessel counts and associated probability of floodlight use in close proximity of their only breeding colony, number of WHDP commutes, duration of phenophases, and ultimately the cumulative exposure to floodlights using a Bayesian framework. The estimated nightly number of vessels was 0.76 (0.64–0.89), 31% (21%–38%) of which used floodlights. WHDPs were potentially exposed to 28.9 (19.7–39.7) floodlights per breeding period. There was no evidence for inter‐annual variation in vessel counts, floodlight use, or WHDP activity, despite varying environmental conditions. WHDP activity, and therefore risk, was highest during courtship and post‐guard. Yet, there was potential for deck strikes throughout the breeding period, which could impact WHDPs. We identify key research questions (likelihood of a deck strike occurring, survival of deck‐struck birds, and post‐release survival of deck‐struck birds). In the meantime, small behavioral changes of vessel operators could be a successful approach to protecting seabirds from offshore ALAN. Tuhinga whakarāpopoto Ko te rama tāwhai ite pō (ALAN) he mea whakamōrearea i te rerenga rauropi, engari ko ngā pānga ote ALAN ki ngā manu moana ki tai kāore anō kia āta whakamāramatia. Ko ngāāhuatanga kāore anō kia āta tātari ko te tukinga kāraho (ko te tūtukinga o ngāmanu moana e tāhurihuri ana ki ngā waka, nā te ALAN). Ki te whakapae atu i temōreareatanga o te tukinga kāraho ki te Kuaka Whenua Hou (Pelecanoideswhenuahouensis; WHDP) he manu e ngaro haere ana tōna whare ora, i whakatau tatate tini o ngā waka e tere i te pō me te tūponotanga e hāngai ana ki tewhakamahinga o te tūrama raharaha e pātata ana ki pūrei kōhanga anake ō rātou,te maha o ngā rerenga o ngā WHDP, te roa o te tauwāhi mātai, ā, i te otinga kuawhakamahia te anga ‘Bayesian’ ki te ine i ngā pānga tapeke o ēnei manu ki ērārama. Ko te whakatau tata o te maha o ngā waka i ia pō ko te 0.76 (0.64‐.089),31% (21%‐38%) o ēnei i whakamahia ngā tūrama rarharaha. I hōrakerake ai pea ngāWHDP kia 28.9 (19.7‐39.7) ngā wā i ia wā whakatipu. Kāore he taunakitanga i tererekētanga o te maha o ngā waka, te whakamahinga o te tūrama raharaha, te mahio te WHDP i waenga i ngā tau, ahakoa he rerekē ngā āhuatanga o te taiao. Ko temahi a ngā WHDP, waihoki ko te pānga o te mōrearea ki a rātou hoki, kua pikiake i te wā o te whakaipoipo, ā, mō muri hoki i tā rātou tūtei hua. Arā tonu tepitomata ka tukia pea te kāraho i te wā katoa o te wa whakatīpu, mā reira e pākino ai ki ngā WHDP. Ka tūtohutia e mātou ngā pātai rangahau matua (tetingatanga o te tukinga kāraho, te oranga tonutanga rānei o te manu kua tukia kite kāraho, me te oranga tonutanga o te manu kua whakamātūtū, ā, kua whakahokiakētia ki tōna ao). Āianei, mā te paku panonihanga o ngā whanonga hautū waka ongā kaihautū waka ka tiaki pai ngā manu moana i te ALAN ki tai.

We use data from motion-activated remote cameras to document a commensal, and possibly mutualistic, relationship between Bornean Ground Cuckoos and Bearded Pigs in the rainforests of Kalimantan, Indonesia. We hypothesise that birds benefiting from symbiotic relationships may suffer indirect detrimental effects from hunting that targets large mammals in tropical rainforests.

Mountain caribou are an endangered ecotype of woodland caribou (Rangifer tarandus caribou) that live in highprecipitation, mountainous ecosystems of southeastern British Columbia and northern Idaho. The distribution and abundance of these caribou have declined dramatically from historical figures. Results from many studies have indicated that mountain caribou rely on old conifer forests for several life-history requirements including an abundance of their primary winter food, arboreal lichen, and a scarcity of other ungulates and their predators. These old forests often have high timber value, and understanding mountain caribou ecology at a variety of spatial scales is thus required to develop effective conservation strategies. Here we summarize results of studies conducted at three different spatial scales ranging from broad limiting factors at the population level to studies describing the selection of feeding sites within seasonal home ranges of individuals. The goal of this multi-scale review is to provide a more complete picture of caribou ecology and to determine possible shifts in limiting factors across scales. Our review produced two important results. First, mountain caribou select old forests and old trees at all spatial scales, signifying their importance for foraging opportunities as well as conditions required to avoid alternate ungulates and their predators. Second, relationships differ across scales. For example, landscapes dominated by roads and edges negatively affect caribou survival, but appear to attract caribou during certain times of the year. This juxtaposition of fine-scale behaviour with broad-scale vulnerability to predation could only be identified through integrated multi-scale analyses of resource selection. Consequently we suggest that effective management strategies for endangered species require an integrative approach across multiple spatial scales to avoid a focus that may be too narrow to maintain viable populations. Abstract in Norwegian / Sammendrag: Skala-avhengig økologi og truet fjellvillrein i Britisk Columbia Fjellvillreinen i de nedbørsrike fjellområdene i sørøstre Britisk Columbia og nordlige Idaho som er en truet økotype av skogsreinen (Rangifer tarandus caribou), har blitt kraftig redusert både i utbredelse og antall. Mange studier har vist at denne økotypen er avhengig av vinterføden hengelav i gammel barskog hvor det også er få andre klovdyr og dermed få predatorer. Slik skog er også viktige hogstområder, og å forstå økologien til fjellvillreinen i forskjellige skaleringer er derfor nødvendig for å utvikle forvaltningsstrategier som kan berge og ta vare på denne reinen. Artikkelen gir en oversikt over slike arbeider: fra studier av begrensende faktorer på populasjonsnivå til studier av sesongmessige beiteplasser på individnivå. Hensikten er å få frem et mer helhetlig perspektiv på fjellvillreinen og finne hvordan de begrensende faktorene varierer etter skaleringen som er benyttet i studiet. Oversikten vår frembragte to viktige resultater; 1) Uansett skalering så velger dyrene gammel skog og gamle trær. 2) Dyrenes bruk av et område kan variere med benyttet skalering, for eksempel vil landskap utbygd med veier og hogstflater være ufordelaktig for overlevelsen, men synes likevel å kunne tiltrekke fjellvillreinen til visse tider av året. Forholdet mellom atferd ut fra fin-skalering og stor-skalering sårbarhet hva gjelder predasjon, ville kun blitt avdekket ved flere-skaleringsanalyse av hvordan ressursene benyttes. Ut fra dette foreslår vi at forvaltningsstrategier for truete bestander som eksempelvis fjellvillreinen, må baseres på tilnærminger ut fra ulike skaleringer for å hindre at et for snevert perspektiv kan begrense muligheten for vedvarende levedyktighet.

Unresolved taxonomy of threatened species is problematic for conservation as the field relies on species being distinct taxonomic units. Differences in breeding habitat and results from a preliminary molecular analysis indicated that the New Zealand population of the South Georgian Diving Petrel (Pelecanoides georgicus) was a distinct, yet undescribed, species. We measured 11 biometric characters and scored eight plumage characters in 143 live birds and 64 study skins originating from most populations of P. georgicus, to assess their taxonomic relationships. We analysed differences with principal component analyses (PCA), factorial ANOVAs, and Kruskal-Wallis rank sum tests. Results show that individuals from New Zealand differ significantly from P. georgicus from all other populations as following: 1) longer wings, 2) longer outer tail feathers, 3) deeper bills, 4) longer heads, 5) longer tarsi, 6) limited collar extent, 7) greater extent of contrasting scapulars, 8) larger contrasting markings on the secondaries, 9) paler ear coverts, 10) paler collars, and 11) paler flanks. Furthermore, we used a species delimitation test with quantitative phenotypic criteria; results reveal that the New Zealand population of P. georgicus indeed merits species status. We hereby name this new species Pelecanoides whenuahouensis sp. nov. Due to severe reductions in its range and the very low number of remaining birds (~150 individuals limited to a single breeding colony on Codfish Island/Whenua Hou) the species warrants listing as 'Critically Endangered'. An abstract in the Māori language/Te Reo Māori can be found in S1 File.

Mate selection influences individual fitness, is often based on complex cues and behaviours, and can be difficult to study in solitary species including carnivores. We used motion-triggered cameras at 29 community scrapes (i.e. scent marking locations used by multiple individuals) and home range data from 39 GPS-collared pumas (Puma concolor) to assess the relevance of communication behaviours for mate selection by female pumas in California. Female pumas visited community scrapes irregularly and visitation bouts appeared to be correlated with oestrus. Female pumas on average selected from 1.7 collared males, and selection was based on multiple cues that varied among the different time periods measured (i.e. the female's visitation bout and in 90 days previous to the consorting event). Female mate selection over the course of a visitation bout was based on frequency of the male visitation, mass, and age. In the 90 days previous to consorting, the number of scrapes a male created was the most important contributor to selection, which was likely related to his residency status. We also found that at least 14% of females mated with multiple males, thus possibly confusing paternity. Our findings provide a mechanistic understanding of how female pumas use scent and auditory communication at community scrapes to select dominant resident males to mate with.

Scavenging is a widespread behaviour and an important process influencing food webs and ecological communities. Large carnivores facilitate the movement of energy across trophic levels through the scavenging and decomposition of their killed prey, but competition with large carnivores is also likely to constrain acquisition of carrion by scavengers. We used an experimental approach based on motion-triggered video cameras at black-tailed deer (Odocoileus hemionus columbianus) carcasses to measure the comparative influences of two large carnivores in the facilitation and limitation of carrion acquisition by scavengers. We found that pumas (Puma concolor) and black bears (Ursus americanus) had different effects on their ecological communities. Pumas, as a top-level predator, facilitated the consumption of carrion by scavengers, despite significantly reducing their observed sum feeding times (165.7 min ± 21.2 SE at puma kills 264.3 min ± 30.1 SE at control carcasses). In contrast, black bears, as the dominant scavenger in the system, limited consumption of carrion by scavengers as evidenced by the observed reduction of scavenger species richness recorded at carcasses where they were present (mean = 2.33 ± 0.28 SE), compared to where they were absent (mean = 3.28 ± 0.23 SE). Black bears also had large negative effects on scavenger sum feeding times (88.5 min ± 19.8 SE at carcasses where bears were present, 372.3 min ± 50.0 SE at carcasses where bears were absent). In addition, we found that pumas and black bears both increased the nestedness (a higher level of order among species present) of the scavenger community. Our results suggest that scavengers have species-specific adaptions to exploit carrion despite large carnivores, and that large carnivores influence the structure and composition of scavenger communities. The interactions between large carnivores and scavengers should be considered in future studies of food webs and ecological communities.

Predation risk describes the energetic cost an animal suffers when making a trade off between maximizing energy intake and minimizing threats to its survival. We tested whether Andean condors (Vultur gryphus) influenced the foraging behaviors of a top predator in Patagonia, the puma (Puma concolor), in ways comparable to direct risks of predation for prey to address three questions: 1) Do condors exact a foraging cost on pumas?; 2) If so, do pumas exhibit behaviors indicative of these risks?; and 3) Do pumas display predictable behaviors associated with prey species foraging in risky environments? Using GPS location data, we located 433 kill sites of 9 pumas and quantified their kill rates. Based upon time pumas spent at a carcass, we quantified handling time. Pumas abandoned >10% of edible meat at 133 of 266 large carcasses after a single night, and did so most often in open grasslands where their carcasses were easily detected by condors. Our data suggested that condors exacted foraging costs on pumas by significantly decreasing puma handling times at carcasses, and that pumas increased their kill rates by 50% relative to those reported for North America to compensate for these losses. Finally, we determined that the relative risks of detection and associated harassment by condors, rather than prey densities, explained puma "giving up times" (GUTs) across structurally variable risk classes in the study area, and that, like many prey species, pumas disproportionately hunted in high-risk, high-resource reward areas.