Cathartes Aura Research Articles

Conservation Letter: Raptors and Anticoagulant Rodenticides

Conservation Letter: Raptors and Anticoagulant Rodenticides

Responses of turkey vultures to unmanned aircraft systems vary by platform

A challenge that conservation practitioners face is manipulating behavior of nuisance species. The turkey vulture (Cathartes aura) can cause substantial damage to aircraft if struck. The goal of this study was to assess vulture responses to unmanned aircraft systems (UAS) for use as a possible dispersal tool. Our treatments included three platforms (fixed-wing, multirotor, and a predator-like ornithopter [powered by flapping flight]) and two approach types (30 m overhead or targeted towards a vulture) in an operational context. We evaluated perceived risk as probability of reaction, reaction time, flight-initiation distance (FID), vulture remaining index, and latency to return. Vultures escaped sooner in response to the fixed-wing; however, fewer remained after multirotor treatments. Targeted approaches were perceived as riskier than overhead. Vulture perceived risk was enhanced by flying the multirotor in a targeted approach. We found no effect of our treatments on FID or latency to return. Latency was negatively correlated with UAS speed, perhaps because slower UAS spent more time over the area. Greatest visual saliency followed as: ornithopter, fixed-wing, and multirotor. Despite its appearance, the ornithopter was not effective at dispersing vultures. Because effectiveness varied, multirotor/fixed-wing UAS use should be informed by management goals (immediate dispersal versus latency).

Microscopic Analysis of the Plumulaceous Feather Characteristics of Cathartiformes and Accipitriformes in North America

ABSTRACT Although variation in microscopic plumulaceous (downy) feather characters is known to be useful in taxonomic identifications of birds, the conserved characters unique to most avian orders remain understudied. We examined plumulaceous feather characters (morphometric and observed pigmentation patterns [qualitative]) within three avian families (Cathartidae, Pandionidae, Accipitridae) occurring in North America that often require taxonomic identification based on incomplete or fragmentary remains. We found significant quantitative differences among these three families for measurements of barbule length, node width, average number of nodes per barbule, and internode length. We observed additional differences in pigmentation patterns and spine distribution at nodes. Differences in pigment patterns and intensity are diagnostic for distinguishing Black Vulture (Coragyps atratus) from Turkey Vulture (Cathartes aura) within Cathartidae. Further observed differences of a higher percentage of spined structures present at node junctions along the length of barbules are diagnostic of Pandionidae. Within Accipitridae, pigmentation patterns and pigment intensity separate Swallow-tailed Kite (Elanoides forficatus) and White-tailed Kite (Elanus leucurus) from all other taxa; and barbule length, together with average nodes per barbule is unique to Northern Harrier (Circus hudsonius) in the families examined in this study. Although significant differences in a combination of microscopic feather characters among species were seldom observed in this study, family level differences were consistently documented. Results support the use of a suite of microscopic characters in combination with macroscopic feather features, geographic distributions, molecular methods, and other circumstantial evidence to aid in the identification of species of birds from feathers.

The taphonomic impact of scavenger guilds in southern Quebec during summer and fall in two distinct habitats.

Decomposition of human remains is a complex process impacted by many intrinsic and extrinsic factors. A less-studied extrinsic factor in forensic taphonomy are the scavengers that consume soft and hard tissue. Scavengers physically degrade and remove soft tissue, disperse, and destroy skeletal elements, which can make locating remains challenging. While invertebrate activity has been largely investigated, there is limited quantitative data available on vertebrate activity, particularly in Canada. This study aimed to determine which species (vertebrate and invertebrate) belong to the scavenger guilds in southern Quebec, and their potential taphonomic impact on the decomposition process. Two independent trials were conducted in 2020 using pig carcasses: one during summer in a forest habitat and one during fall in a grassland habitat. Each carcass was placed a minimum 100m apart in semi-rural land. Vertebrate scavenger activity was recorded by continuous surveillance using trail cameras. Carcasses were also regularly visited to monitor the decomposition process and the activity of invertebrate scavengers. Overall, the vertebrate scavenger guilds included a narrow range of corvids, turkey vultures, coyotes, and skunks. The intensity of vertebrate scavengers was greater in the grassland habitat (fall), while the intensity of invertebrate scavengers was greater in the forest habitat (summer). With the exception of invertebrate scavengers, very few species visited during the fresh stage of decomposition, and the probability of body displacement increased as decomposition progressed. These results identify which scavengers have the greatest taphonomic impact and highlight the importance of incorporating scavenger impact when searching for human remains.

Scavengers reduce potential brucellosis transmission risk in the Greater Yellowstone Ecosystem

AbstractScavengers likely play an important role in ecosystem energy flow as well as disease transmission, but whether they facilitate or reduce disease transmission is often unknown. In the Greater Yellowstone Ecosystem, scavengers are likely to reduce the transmission and subsequent spread of brucellosis within and between livestock and elk by consuming infectious abortion materials, thereby removing the infectious agent from the landscape. We used remote cameras to monitor the time to removal of simulated abortion materials by scavengers at 264 sites from February to June in 2017 and 2018 and assessed the effects of habitat and land management on time to removal in southwest Montana. Time to removal of fetal materials decreased in grassland habitats ( = 2.9 d, credible interval = [1.8–5.0]) in comparison to sagebrush habitats ( = 5.4 d [3.4–9.3]) and forest habitats ( = 5.2 d [3.3–9.0]). In addition, there was an 88% probability that time to removal of fetal materials was slower at sites where mammalian scavengers were actively reduced ( = 6.5 d [3.4–12.8]) compared to sites with no scavenger reduction ( = 4.1 d [2.3–7.8]). Our research indicates that if elk and livestock are commingling during the brucellosis risk period, there is a 90% probability that abortion materials will be removed by scavengers within 16 d across all sites. Coyotes, red foxes, golden and bald eagles, Corvus spp., and turkey vultures were the dominant scavengers, removing 90% of the fetal materials. Actions to maintain the breadth and diversity of scavengers on the landscape are potential management options that could reduce disease transmission risk to livestock in a system where the wildlife reservoir is difficult to address.

Emerging Pathogenic Gammaproteobacteria Wohlfahrtiimonas chitiniclastica and Ignatzschineria Species in a Turkey Vulture (Cathartes aura).

New World vultures, such as turkey vultures (Cathartes aura), are obligate scavengers with large geographic ranges. In a preliminary characterization of the turkey vulture (TV) gastrointestinal microbiome in Southern California, we identified 2 recently described emerging bacterial pathogens not previously known to be associated with this avian species. High-throughput sequencing of broad-range 16S rRNA gene amplicons revealed sequences from TV cloacal swabs that were related closest to Wohlfahrtiimonas chitiniclastica and Ignatzschineria species, both Gammaproteobacteria considered by the United States Centers for Disease Control and Prevention as emerging zoonotic pathogens. None of these bacterial sequence types have been previously identified from samples obtained from the turkey vulture gastrointestinal microbiome. With the use of bioinformatics workflows previously established by our research group, we designed specific and sensitive polymerase chain reaction primer sets that represent novel diagnostic assays for the genera Wohlfahrtiimonas and Ignatzschineria. These primer sets were validated by Sanger sequence confirmation from complex TV samples. Because the genera Wohlfahrtiimonas and Ignatzschineria are both known to have dipteran hosts, the molecular diagnostic tools we present here should be useful for better understanding the role of flies, vultures, and other scavengers in the ecology and epidemiology of the genera Wohlfahrtiimonas and Ignatzschineria from a One Health perspective.

Vulture Abundance and Habitat Association Following Major Hurricane Disturbance in the Tropical Dry Forest of Western Mexico

Scavenger birds are common species frequently associated with open habitats, but sympatric vulture species have differing natural history traits that may influence seasonal habitat relationships and responses to natural disturbances, such as hurricanes. We evaluated seasonality and habitat relationships of Black Vultures (Coragyps atratus) and Turkey Vultures (Cathartes aura) at sites within and outside the path of maximum winds of Hurricane Patricia in western Mexico. We used 1.5-km line transects to survey vultures during dry and rainy seasons in four habitats of the tropical dry forest biome over a 2-yr period after hurricane landfall. We measured habitat structure along each transect using the point-centered quarter method, and determined landscape composition within a 3000-ha circular plot centered around the midpoint of each transect. Vulture abundance was influenced by habitat structure variables of open areas, but at sites affected by hurricane disturbance vulture abundance was positively associated with increased cover of wetlands and agricultural land. Both species of vultures had low abundance in forests, and Black Vultures had significantly higher abundance in agricultural land and wetlands. Season significantly influenced vulture abundance by habitat: agricultural land and wetlands had higher vulture abundance in the rainy season, but forests had higher abundance in the dry season. Disturbance by a major hurricane induced species-specific changes in spatial-temporal abundance of vultures: the Black Vulture in particular had higher abundance in all habitats except wetlands during the dry season, and greater abundance in the first months after hurricane landfall. Hence, although vultures occur predominantly in open areas, they show species-specific habitat associations and responses to hurricane disturbance.

Landscape transformations produce favorable roosting conditions for turkey vultures and black vultures

Recent increases in turkey vulture (Cathartes aura) and black vulture (Coragyps atratus) populations in North America have been attributed in part to their success adapting to human-modified landscapes. However, the capacity for such landscapes to generate favorable roosting conditions for these species has not been thoroughly investigated. We assessed the role of anthropogenic and natural landscape elements on roosting habitat selection of 11 black and 7 turkey vultures in coastal South Carolina, USA using a GPS satellite transmitter dataset derived from previous research. Our dataset spanned 2006–2012 and contained data from 7916 nights of roosting. Landscape fragmentation, as measured by land cover richness, influenced roosting probability for both species in all seasons, showing either a positive relationship or peaking at intermediate values. Roosting probability of turkey vultures was maximized at intermediate road densities in three of four seasons, and black vultures showed a positive relationship with roads in fall, but no relationship throughout the rest of the year. Roosting probability of both species declined with increasing high density urban cover throughout most of the year. We suggest that landscape transformations lead to favorable roosting conditions for turkey vultures and black vultures, which has likely contributed to their recent proliferations across much of the Western Hemisphere.

Inclement weather forces stopovers and prevents migratory progress for obligate soaring migrants

BackgroundMigrating birds experience weather conditions that change with time, which affect their decision to stop or resume migration. Soaring migrants are especially sensitive to changing weather conditions because they rely on the availability of environmental updrafts to subsidize flight. The timescale that local weather conditions change over is on the order of hours, while stopovers are studied at the daily scale, creating a temporal mismatch.MethodsWe used GPS satellite tracking data from four migratory Turkey Vulture (Cathartes aura) populations, paired with local weather data, to determine if the decision to stopover by migrating Turkey Vultures was in response to changing local weather conditions. We analyzed 174 migrations of 34 individuals from 2006 to 2019 and identified 589 stopovers based on variance of first passage times. We also investigated if the extent of movement activity correlated with average weather conditions experienced during a stopover, and report general patterns of stopover use by Turkey Vultures between seasons and across populations.ResultsStopover duration ranged from 2 h to more than 11 days, with 51 % of stopovers lasting < 24 h. Turkey Vultures began stopovers immediately in response to changes in weather variables that did not favor thermal soaring (e.g., increasing precipitation fraction and decreasing thermal updraft velocity) and their departure from stopovers was associated with improvements in weather that favored thermal development. During stopovers, proportion of activity was negatively associated with precipitation but was positively associated with temperature and thermal updraft velocity.ConclusionsThe rapid response of migrating Turkey Vultures to changing weather conditions indicates weather-avoidance is one of the major functions of their stopover use. During stopovers, however, the positive relationship between proportion of movement activity and conditions that promote thermal development suggests not all stopovers are used for weather-avoidance. Our results show that birds are capable of responding rapidly to their environment; therefore, for studies interested in external drivers of weather-related stopovers, it is essential that stopovers be identified at fine temporal scales.

High Levels of Heavy Metals detected in Feathers of an Avian Scavenger Warn of a High Pollution Risk in the Atacama Desert (Chile).

The Atacama Desert represents the highest levels of mining exploitation in Chile, which inexorably results in high levels of pollution. Raptors, and particularly scavengers, have shown their usefulness to evaluate exposure to environmental contaminants in polluted scenarios. In this study, we used primary feathers from a local avian scavenger, turkey vulture Cathartes aura, to evaluate the exposure to cadmium (Cd), lead (Pb), copper (Cu) and zinc (Zn) in two locations from the southern Atacama Desert (coastal and inland) and a third location from the bordering semiarid region, in northern Chile. All metals were detected in all analyzed samples (n = 54). Mean concentrations in Coastal Atacama were 0.68 ± 0.84ppm for Cd; 1.97 ± 2.01ppm for Pb; 59.11 ± 80.69ppm for Cu; and 107.96 ± 51.00ppm for Zn, while mean concentrations in Inland Atacama were 0.55 ± 0.42ppm for Cd; 3.37 ± 2.61ppm for Pb; 91.66 ± 77.74ppm for Cu; and 214.03 ± 99.08ppm for Zn. Mean concentrations in Coastal Coquimbo were 0.63 ± 0.69ppm for Cd; 1.57 ± 0.92ppm for Pb; 18.09 ± 6.12ppm for Cu; and 149.37 ± 105.56ppm for Zn. These differences could be explained by differences on abundance of mining settlements among areas. According to the literature, these values are very high for all metals, exceeding in some cases those values referred as responsible of health disorders in birds. We strongly recommend further research looking at potential adverse effects caused by heavy metal pollution on the health of human and wildlife populations in the southern Atacama Desert.

Anthrax Surveillance and the Limited Overlap Between Obligate Scavengers and Endemic Anthrax Zones in the United States.

Anthrax is a zoonosis caused by the spore-forming bacterium Bacillus anthracis, with potential for high fatality rate, especially in herbivores. Upon host death, spores can enter the soil surrounding the carcass and be ingested by other animals feeding in the same location. Accordingly, surveillance to quickly identify and decontaminate anthrax carcasses is crucial to outbreak prevention. In endemic anthrax areas such as Texas and Africa, vultures are used as a surveillance tool for identifying presence and location of dead animals. However, many anthrax outbreaks in the United States have occurred in areas outside the ranges of both black and turkey vultures. Here, we used a longitudinal camera trap survey at carcass sites in southwestern Montana to investigate the utility of facultative avian scavengers on disease and carcass surveillance in a reemerging anthrax risk zone. From August 2016 to September 2018, camera traps at 11 carcass sites were triggered 1996 times by avian scavengers. While the majority were facultative avian scavengers such as corvids and eagles, our results suggest that facultative scavengers cannot replace vultures as a surveillance tool in this ecosystem due to their absence during the anthrax risk period (June to August), reduced search efficiency, or low flight patterns. We found that the conditions in Montana likely parallel systems elsewhere in the continental United States. Using ecological niche models of B. anthracis distribution overlaid with relative abundance maps of turkey vultures, we found that much of North Dakota, South Dakota, Minnesota, Wyoming, Nebraska, and Iowa have areas of anthrax risk, but low or absent turkey vulture populations. Without vultures in these areas, surveillance capacity is reduced, and it becomes more difficult to identify anthrax cases, meaning fewer carcasses are decontaminated, and consequently, outbreaks could become more frequent or severe.

Demographic and potential biological removal models identify raptor species sensitive to current and future wind energy

AbstractA central challenge in applied ecology is understanding the effect of anthropogenic fatalities on wildlife populations and predicting which populations may be particularly vulnerable and in greatest need of management attention. We used three approaches to investigate the potential effects of fatalities from collisions with wind turbines on 14 raptor species for both current (106 GW) and anticipated future (241 GW) levels of installed wind energy capacity in the United States. Our goals were to identify species at relatively high vs low risk of experiencing population declines from turbine collisions and to also compare results generated from these approaches. Two of the approaches used a calculated turbine‐caused mortality rate to decrement population growth, where population trends were derived either from the North American Breeding Bird Survey or from a matrix model parameterized from literature‐derived demographic values. The third approach was potential biological removal, which estimates the number of fatalities that allow a population to reach and maintain its optimal sustainable population set by management objectives. Different results among the methods reveal substantial gaps in knowledge and uncertainty in both demographic parameters and species‐specific estimates of fatalities from wind turbines. Our results suggest that, of the 14 species studied, those with relatively higher potential of population‐level impacts from wind turbine collisions included barn owl, ferruginous hawk, golden eagle, American kestrel, and red‐tailed hawk. Burrowing owl, Cooper’s hawk, great horned owl, northern harrier, turkey vulture, and osprey had a relatively lower potential for population impacts, and results were not easily interpretable for merlin, prairie falcon, and Swainson’s hawk. Projections of current levels of fatalities to future wind energy scenarios at 241 GW of installed capacity suggest some species could experience population declines because of turbine collisions. Populations of those species may benefit from research to identify tools to prevent or reduce raptor collisions with wind turbines.

Genome-wide diversity in the California condor tracks its prehistoric abundance and decline

Due to their small population sizes, threatened and endangered species frequently suffer from a lack of genetic diversity, potentially leading to inbreeding depression and reduced adaptability.1 During the latter half of the twentieth century, North America's largest soaring bird,2 the California condor (Gymnogyps californianus; Critically Endangered3), briefly went extinct in the wild. Though condors once ranged throughout North America, by 1982 only 22 individuals remained. Following decades of captive breeding and release efforts, there are now >300 free-flying wild condors and ∼200 in captivity. The condor's recent near-extinction from lead poisoning, poaching, and loss of habitat is well documented,4 but much about its history remains obscure. To fill this gap and aid future management of the species, we produced a high-quality chromosome-length genome assembly for the California condor and analyzed its genome-wide diversity. For comparison, we also examined the genomes of two close relatives: the Andean condor (Vultur gryphus; Vulnerable3) and the turkey vulture (Cathartes aura; Least Concern3). The genomes of all three species show evidence of historic population declines. Interestingly, the California condor genome retains a high degree of variation, which our analyses reveal is a legacy of its historically high abundance. Correlations between genome-wide diversity and recombination rate further suggest a history of purifying selection against linked deleterious alleles, boding well for future restoration. We show how both long-term evolutionary forces and recent inbreeding have shaped the genome of the California condor, and provide crucial genomic resources to enable future research and conservation.

Filoplume morphology covaries with their companion primary suggesting that they are feather-specific sensors

Abstract Do birds detect and respond to forces acting on feathers through filoplumes, which appear to be unique mechanosensory feathers? If filoplumes function as sensors, their morphology should covary with the morphology of their companion feather to better detect feather movements and position. We explore covariation in filoplumes and primaries across 5 species of birds that vary in body size, molt strategy, and the functional life span of their primaries (Green-winged Teal [Anas crecca], Ring-billed Gull [Larus delawarensis], Turkey Vulture [Cathartes aura], Red-tailed Hawk [Buteo jamaicensis], and Red-winged Blackbird [Agelaius phoeniceus]). Filoplumes never extended beyond the coverts and inserted immediately adjacent to the base of their companion primaries, positioning them to detect subtle changes in feather vibration or movement. Far more variation in filoplume number and morphology was due to species differences than to individuals or position in the wing. Across species, filoplume length and number increased with calamus length of primaries. In the 2 species with growing primaries, the number and length of filoplumes were only weakly associated with molting primaries, suggesting that filoplumes were not replaced when their companion primary was replaced. Further, filoplumes associated with a growing primary were not replaced synchronously, leaving others to sense primary position and movement. Finally, filoplume number and length were greatest in Red-tailed Hawks, a species that carries individual feathers for multiple years, but links between filoplume morphology and molt strategy await broader comparative studies. Taken together, the morphology of filoplumes and their replacement schedule relative to their associated primary suggests that they are sensors, capable of detecting subtle differences in the position and movement of their companion feathers.

Factors influencing scavenger guilds and scavenging efficiency in Southwestern Montana

Scavenging of carrion shapes ecological landscapes by influencing scavenger population demography, increasing inter- and intra-specific interactions, and generating ecosystem services such as nutrient cycling and disease moderation. Previous research found the cues promoting, or the constraints limiting, an individual’s propensity or ability to scavenge vary widely, depending on anthropogenic and environmental factors. Here we investigated differences in scavenging patterns in a complex scavenger guild in Southwestern Montana. We used camera traps established at 13 carcass sites to monitor carcass detection, visitation, and consumption times, during 2016–2018 and generalized linear models to explore the influence of carcass characteristics, habitat features, and seasonality, on carcass selection and scavenging efficiency. We found that scavenger species diversity was higher at higher elevations and in grassland habitats. Scavenging efficiency was influenced inter alia by seasonality, distance to water, and elevation. We found that most carcass consumption was via facultative scavengers (bears, wolves, magpies, Corvus spp.) rather than turkey vultures, the only obligate scavengers in the study area. However, growing populations of turkey vultures may lead to increased competition with facultative scavengers over carrion, and could have cascading effects on food webs in this ecosystem.

Yearly temperature fluctuations and survey speed influence road counts of wintering raptors

Globally, evaluation of population trends is the most pressing research need for many species of conservation concern. Road counts for birds of prey are useful for monitoring long‐term population trends and examining year‐to‐year variations in abundance. We examined data from 2155 road surveys conducted from 2001 to 2018 by community scientists who recorded &gt; 85 000 individuals of 14 species of raptors while participating in the Pennsylvania Winter Raptor Survey, in Pennsylvania, USA. We estimated abundance and population growth rates while accounting for observation error by using dynamic Bayesian state‐space models. Model estimates indicated that counts of wintering Bald Eagles Haliaeetus leucocephalus, Red‐shouldered Hawks Buteo lineatus and Black Vulture Coragyps atratus increased over the course of the study. Counts of Rough‐legged Buzzard Buteo lagopus, Red‐tailed Hawk Buteo jamaicensis, Northern Harrier Circus hudsonius, Turkey Vulture Cathartes aura and American Kestrel Falco sparverius varied more (CV &gt; 5.0) over the duration of the study than other species did. Higher winter temperatures were associated with increases in counts of species whose local populations are partially migratory (American Kestrel and Red‐tailed Hawk), and with lower counts of a long‐distance arctic migrant – Rough‐legged Buzzard. Counts of these species were therefore correlated such that more American Kestrels and Red‐tailed Hawks were counted during years when Rough‐legged Buzzards were less frequently seen. Generally, the number of individuals counted declined as survey speed increased. A general rule for road counts therefore seems to be ‘slower is better’, consistent with past recommendations that observers travel at a speed &lt; 40 km/h during road counts. Our study highlights the utility of road surveys and advances analytical approaches to monitor raptors.

The complete mitochondrial genome of Gyps coprotheres (Aves, Accipitridae, Accipitriformes): phylogenetic analysis of mitogenome among raptors.

Three species of Old World vultures on the Asian peninsula are slowly recovering from the lethal consequences of diclofenac. At present the reason for species sensitivity to diclofenac is unknown. Furthermore, it has since been demonstrated that other Old World vultures like the Cape (Gyps coprotheres; CGV) and griffon (G. fulvus) vultures are also susceptible to diclofenac toxicity. Oddly, the New World Turkey vulture (Cathartes aura) and pied crow (Corvus albus) are not susceptible to diclofenac toxicity. As a result of the latter, we postulate an evolutionary link to toxicity. As a first step in understanding the susceptibility to diclofenac toxicity, we use the CGV as a model species for phylogenetic evaluations, by comparing the relatedness of various raptor species known to be susceptible, non-susceptible and suspected by their relationship to the Cape vulture mitogenome. This was achieved by next generation sequencing and assembly. The Cape vulture mitogenome had a genome size of 16,908 bp. The mitogenome phylogenetic analysis indicated a close evolutionary relationship between Old World vultures and other members of the Accipitridae as indicated by bootstrap value of 100% on the phylogenetic trees. Based on this, we postulate that the other species could also be sensitive to the toxic effects of diclofenac. This warrants further investigations.

Plastic ingestion and dispersion by vultures may produce plastic islands in natural areas

Rubbish dumps can become an important environmental source of plastic. Several species feed on organic waste from these sites, but at the same time are exposed to non-organic materials. Species that can gather food in these sites might at the same time disperse waste consumed, but this has rarely been evaluated. We compare the occurrence of plastic debris in regurgitated pellets of three sympatric vultures from northwest Patagonia, Andean condors (Vultur gryphus), black vultures (Coragyps atratus) and turkey vultures (Cathartes aura), foraging in different degrees of humanized sites. We also evaluate the influence of rubbish dumps in the presence of plastic debris in pellets of the studied species and their potential role in spreading plastic to the environment. Most synthetic material present in pellets was plastic. Pellets of Andean condors, which avoid disturbed anthropic sites in this area, showed almost no plastic debris compared with the other sympatric vulture species, suggesting an influence of the foraging habits on plastic ingestion. For black and turkey vultures, we found that rubbish dumps may be an important source of plastic. The occurrence of plastic debris in pellets of black vultures sampled in 2010 and 2020 increased, probably associated with the increase in urbanization and waste production in the study area. Avian scavengers were exposed to and are able to transport plastic to distant communal roosts generating “plastic islands”. It is necessary to reduce plastic generation and better waste management practices to avoid species and environments to be affected by this pollutant.

Interspecific Predatory Waterbird Interactions at a RAMSAR Site

This note describes interactions between four bird species during a predation attempt by Yellow-footed Gull (Larus livens) on an Eared Grebe (Podiceps nigricollis).The interactions among species were documented on video in a mangrove (Rhizophora mangle and Avicennia germinans) area of the Ensenada La Paz (a RAMSAR site) during winter in the southwest Gulf of California, Mexico on 2 February 2019. This is the first report that has documented an effective killing attempt in the Baja California Peninsula and the second in northwestern Mexico of Yellow-footed Gull predation on Eared Grebe. Additionally, kleptoparasitism attempts against the Yellow-footed Gull by a Great Blue Heron (Ardea herodias) and Turkey Vulture (Cathartes aura) are described and suggest that those species may include prey stolen from gulls (family Laridae) more regularly than presently known based on this opportune observation.

Anti-predator behavior of Coimbra-Filho’s titi monkeys (&lt;i&gt;Callicebus coimbrai&lt;/i&gt;)

&#x0D; &#x0D; &#x0D; Predation pressure has an important role in shaping the behavioral, ecological and social patterns of primates. In this study, we describe two types of anti-predator behavior performed by Coimbra-Filho’s titi monkeys (Callicebus coimbrai), and compare our reports with the anti-predator strategies adopted by other Neotropical primates. The reports were performed on a small and isolated Atlantic forest fragment (14 ha) located in a highly-fragmented landscape in north-eastern Brazil. Although the titi monkey group was systematically monitored (July/2009 - August/2012: 1,513 hours) over the years, the events were recorded ab libitum method. Four events of anti-predator behavior were reported: three were in response to a medium-sized arboreal primate, the yellow-breasted capuchin monkey (Sapajus xanthosternos), and one in response to a large bird, the turkey vulture (Cathartes aura). When in the presence of S. xanthosternos, the titi monkeys emitted a quiet alert vocalization and descended to the dense undergrowth in order to avoid predation. On the other hand, when the titi monkeys were exploiting fleshy fruit on a tree, they verified the presence of an individual of C. aura and jumped to the ground. Both types of anti-predator behavior had been previously described for Neotropical primates. The anti-predator behaviors performed by the titi monkeys can contribute to the understanding of the adaptive processes of these poorly studied primates in fragmented habitats. Moreover, the passive behavior and the habitat characteristics may be an important aspect in the choice of strategy to be used, since the habitat pro- vided adequate refuges and allowed the titi monkeys to seek an alternative escape route.&#x0D; &#x0D; &#x0D;