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.

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.

Host Bloodmeal Identification in Cave-Dwelling Ornithodoros turicata Dugès (Ixodida: Argasidae), Texas, USA

Tick-host bloodmeal associations are important factors when characterizing risks of associated pathogen transmission and applying appropriate management strategies. Despite their biological importance, comparatively little is known about soft tick (Argasidae) host associations in the United States compared to hard ticks (Ixodidae). In this study, we evaluated a PCR and direct Sanger sequencing method for identifying the bloodmeal hosts of soft ticks. We collected 381 cave-associated Ornithodoros turicata near San Antonio, Texas, USA, and also utilized eight colony-reared specimens fed artificially on known host blood sources over 1.5 years ago. We correctly identified the vertebrate host bloodmeals of two colony-reared ticks (chicken and pig) up to 1,105 days post-feeding, and identified bloodmeal hosts from 19 out of 168 field-collected soft ticks, including raccoon (78.9%), black vulture (10.5%), Texas black rattlesnake (5.3%), and human (5.3%). Our results confirm the retention of vertebrate blood DNA in soft ticks and advance the knowledge of argasid host associations in cave-dwelling O. turicata.

Population Viability and Conservation Strategies for the Eurasian Black Vulture (Aegypius monachus) in Southeast Europe

The Eurasian Black Vulture is a globally threatened raptor that in Southeast Europe only occurs in an isolated population in Greece. We examined the population viability for the species under demographic fluctuations and conservation scenarios. The current population showed no possibility of extinction for the next 100 years. However, simulated scenarios showed that the most important factor affecting the viability of the species was medium and high poisoning, leading to 94.8% and 100% probability of extinction, respectively. Furthermore, high reduction of supplementary feeding highlighted an 18.6% extinction possibility. Also, a high increase of wind farms in the area may result in 17.4% extinction possibility. Additionally, the non-establishment of the feeding station in 1987 in the study area would have resulted in an extinction risk of 7%. The species can be translocated to the Olympus National Park by releasing 80 juveniles over 10 years. The implementation of the conservation scenarios concerning the establishment of a supplementary feeding site network, and the reintroduction of the Eurasian Black Vulture in its historic range, along with the elimination of threats posed by poisoning, low food availability, and wind farms would increase the probability of the species persistence and allow the population to become a source for dispersal across Southeast Europe.

An update of the invasive Pterygoplichthys Gill, 1858 (Actinopterygii, Loricariidae) in Guatemala: new records and notes on its interactions with the local fauna

Fishes have been introduced in non-native ecosystems all over the world. These introductions have been recognised for their overall negative effects on native biodiversity. Plecos (Pterygoplichthys Gill, 1858) have been introduced worldwide due to bad practices in the aquarium trade and, in Central America, there is little information regarding these invasive fishes. Plecos have been demonstrated to be a threat in non-native ecosystems because they interfere with their new ecosystems through bottom-up impacts, altering nutrient availability and interactions with native wildlife. Herein, new records of plecos are reported for river basins from Guatemala in northern Central America where they had not previously been reported. Evidence of interactions of plecos with the native fauna that had not been recorded to date are also included. We compiled a total of 34 records in Guatemala, with eight new records. We present the first records of the genus in a river basin of the Caribbean drainage for Guatemala. Three new interactions of fauna preying upon plecos are presented (Black vulture, Bare-throated tiger Heron and Domestic dog), along with a compilation of previously known interactions. Establishing a monitoring and surveillance programme should be a priority in Guatemala, along with other actions to safeguard the native wildlife that could be at high risk because of biological invasions, such as the one with plecos. In order to better understand this invasion, joint efforts of local fishermen and rangers with State institutions should be promoted.

Evolution of the vulture population on a Mediterranean island. The Sardinian instance (Italy)

On the Italian island of Sardinia at the beginning of the 20th century there was still an established population of the Bearded Vulture (about 35 pairs), Black Vulture (about 150 pairs) and the Griffon Vulture was “very common”. However, in the early decades of the 20th century there was a rapid and catastrophic reduction of the vulture populations on Sardinia, with the extinction of Bearded Vulture (1968-69) and the Black Vulture (1961), and the contraction of the population of Griffon Vulture (1000-1400 birds in 1945 to 100-140 birds in 1975 and 12 breeding pairs in 2007). The collection of skins and eggs, followed by hunting, poaching, killing and the use of poisoned baits for pest control were the main causes of the decline of the vultures on Sardinia. These causes were accompanied by an increase of disturbance at the breeding sites, and by a gradual decrease of pastoralism, which has led to a reduction in food availability. More recently, there have been unsuccessful attempts to reintroduce Bearded Vultures and Black Vultures, whereas after various restocking and greater protection projects, the Griffon Vulture population has increased (to 57 pairs and 230-250 birds in 2019). The Egyptian Vulture bred in Sardinia for the first time in 2019. Currently, collection and killing of vultures, and the legal use of poisoned baits have all been removed in Sardinia and the environmental situation now seems appropriate for new attempts to reintroduce the two extinct species.

The Irvingtonian Avifauna of Cumberland Bone Cave, Maryland

The early and mid-Pleistocene avian communities of North America are best known from the Rocky Mountain region and peninsular Florida. In the Appalachian Mountain region, only a small number of avian bones from mid-latitude cave deposits have been attributed to this time period. Here, I enlarge this record by reporting on bird bones from Cumberland Bone Cave in western Maryland, a well-known locality for large and small Irvingtonian mammals and other vertebrates. The taxa identified encompass ground birds, waterfowl, a hawk, two eagles, a vulture, an owl, a jay, a flycatcher, a junco or sparrow, and a finch. No purely boreal elements are confirmed as part of the avian assemblage, and all of the extant species that are positively or tentatively identified in the assemblage still occur in the region today. An immature bone referred to the Black Vulture (Coragyps atratus (Bechstein)) represents an Irvingtonian breeding record for the species in Maryland. This record occurs at the northern limit of the current breeding range for the genus. Extinct species in the assemblage include the Passenger Pigeon (Ectopistes migratorius (Linnaeus)), a large screech owl (Megascops guildayi (Brodkorb & Mourer-Chauviré 1984)), and the large goose, Branta dickeyi Miller 1924. It can be argued that none of these represent the extinction of a phyletic lineage during the Irvingtonian. Based on the broad habitat preferences of modern counterparts of the birds in the assemblage, we can expect that Irvingtonian habitats near the site included mixed forest with mast-producing hardwoods and both early and later successional stages represented. There must have been fluvial, wetland, or lacustrine habitat suitable for waterbirds nearby, and probably also open woodland or grassy savannah areas, suitable for vulture foraging, turkey nesting, and booming by Ruffed Grouse.