Challenges Adapting a Backpack Harness for Use on Gray Hawks (Buteo plagiatus)

ABSTRACT Raptor biologists have successfully used backpack-type harnesses to attach transmitters to a wide range of raptor species for research. As part of a graduate research project with Gray Hawks (Buteo plagiatus) in south Texas, we attached harnesses to 58 individuals and experienced problems with seven birds removing the harnesses and with all females covering the solar panels of the OrniTrack-10 GPS-GSM transmitters, preventing them from functioning properly. We appear to have resolved these issues by trimming nape feathers (short-term solution), switching to a different harness material, stitching through the knots, switching to a different brand of glue, and using a transmitter with an elevated solar panel for females, which are typically larger than males.

Autumn Migration of Diurnal Raptors Across Kenting National Park, Taiwan, Along the East-Asian Oceanic Flyway

ABSTRACT Diurnal raptors were counted during their southward migration in autumn of 2019 at Kenting National Park, southern Taiwan, an important hawkwatch site along the East-Asian Oceanic Flyway. Observations were conducted from 1 September to 31 October 2019 in the morning hours, but the observation period was extended to 1400 H whenever large numbers of raptors passed the site before noon. A total of 329,559 individuals of 14 migratory raptor species was recorded. The Chinese Sparrowhawk (Accipiter soloensis) and Gray-faced Buzzard (Butastur indicus) made up 78.3% (257,971 birds) and 21.6% (71,045 birds) of the total, respectively. The number of Chinese Sparrowhawks increased significantly when we extended the survey duration from 1200 H to 1400 H (paired t-test, t = 2.44, P = 0.04), but the number of Gray-faced Buzzards did not (t = 1.94, P = 0.09). Thus, Chinese Sparrowhawks may continue passing the site en route to the Philippine Islands in the afternoon hours, whereas Gray-faced Buzzards usually stop migrating in early afternoon, at least under certain conditions. How prevailing wind conditions along the East-Asian Oceanic Flyway in autumn shape the different migratory strategies of these two hawk species requires further study.

Commentary: Not All Vulture Feeding Stations Are Supplementary—Proposed Terminology for Carcass Provisioning with Reference to Management Goals and Food Sources

ABSTRACT Although vulture feeding stations are a widely used tool for vulture conservation in many regions worldwide, there has been some confusion about their functions and this is reflected in the range of terminology used. The origin of food supply at provisioning sites (both for in situ and ex situ situations) and the goals of feeding station managers (ranging from purely conservation of vultures to the necessity for carcass disposal) are two key aspects that are often neglected. We review the definitions and nomenclature for the provision of predictable anthropogenic food for vultures and vultures' role in sanitation in the landscape. We propose that “supplementary feeding stations for vultures” (SFSV) defines a particular case and this term should only be applied when a station has vulture conservation goals and a food supply coming from outside of the landscape (ex situ). We introduce the term “recycling station with vultures” (RSV) for cases when the goal is the elimination of carcasses and the food is sourced in situ (natural, NRSV) or ex situ (supplementary food, SRSV). This clarification of goals and terminology for feeding stations worldwide could have important consequences for the understanding and assessment of vulture conservation and management actions, among researchers and conservationists and also importantly among stakeholders and wider society.

First Satellite Telemetry Study of Movement Behavior of Juvenile Golden Eagles from Mexico

ABSTRACT The southern limit of the Golden Eagle's (Aquila chrysaetos) breeding range in North America is Mexico, where the eagle is the national symbol yet designated as a threatened, high priority species for conservation action. Movement information needed for conserving Mexico's Golden Eagles is sparse; knowledge of dispersal from natal areas is essential to understand the eagle's ecology and help provide for its management. Using satellite telemetry data, we analyzed movements of three males and one female from central Mexico during their first year of life; we documented (1) timing and distance of initial dispersal movements, (2) total distance traveled and maximum distance from natal site by month of age following fledging, and (3) size of areas (based on 95% adaptive local convex hulls) across which eagles ranged following initial dispersal. Individual eagles dispersed from their natal areas between mid-September and mid-November, at 6–8 mo of age. Monthly total distance traveled by males reached approximately 350–1350 km at 8–11 mo; the female's peak monthly travel was 3000 km, at age 7 mo. Monthly proximity to natal sites by individuals at ages 8–12 mo was relatively constant, averaging 17.9 km (SD = 5.7) to 129.1 km (SD = 11.3). After dispersal, the monthly ranging areas overall increased during the first year of life for all eagles, especially the female, due mainly to multiple long-distance excursions. Our data suggest that movement behavior of juvenile Golden Eagles from Mexico is mostly similar to that of conspecifics from nonmigratory populations elsewhere. Our study may help serve as a foundation for future work to better understand movement dynamics and resource selection by Mexico's Golden Eagles.

Resurveys Reveal Potential Population Increases of the Himalayan Griffon in Central West Nepal

ABSTRACT The Himalayan Griffon (Gyps himalayensis) is listed as near threatened and its populations are poorly monitored. During late May and early June of 2013, 2014, and 2016, we resurveyed transects that were originally sampled 2002–2006. These transects were within the Annapurna region of Nepal. From 2010 through 2020, we also monitored a breeding colony of Himalayan Griffons within the Arghakhanchi District of Nepal. The number of non-adults, adults, and total Himalayan Griffons counted along the transects approximately doubled from the previous counts. At the colony, the number of breeding pairs and young fledged increased during the study (yearly growth rate [r] = 0.049 and 0.089, respectively). The number of offspring fledged per breeding pair also increased (r = 0.040). Our results are encouraging, but we only surveyed a small portion of the global population and over a relatively short time period. We recommend expanded and coordinated population monitoring for this species across its range.

Historical Accounts Provide Inference into Population Dynamics of American Kestrels (Falco sparverius) in the Northeastern USA

ABSTRACT American Kestrels (Falco sparverius) are declining across much of North America, yet the initial timing of the population decrease is unclear. In an attempt to elucidate when kestrel declines began, we examined historical descriptions of abundance within the northeastern United States. Within The Peregrine Fund's research library, we found 54 descriptions of kestrel abundance in northeastern states dating from 1839 to 2013. Our analysis indicates a cubic trend in descriptions of kestrel abundance with a peak occurring in 1951. After that peak, the population began its current decline, yet the population appears to have been stable beforehand. That the current decline is apparent in our data set lends credence to our methodology and suggests that populations were likely secure until approximately 1951. Our results thus suggest that populations of American Kestrels in the northeastern United States began declining before systematic monitoring began in 1966. Future research should thus examine what environmental changes occurred around the early- to mid-20th century in the northeastern USA to cause population declines of American Kestrels.

Seriemas: A Literature Assessment and Recommendations for Future Research

ABSTRACT Red-legged Seriemas (Cariama cristata) and Black-legged Seriemas (Chunga burmeisteri) are two exclusively South American species that inhabit open and sparsely forested areas. Seriemas have been recently included with the raptors based on ecological and evolutionary evidence. Viewing seriemas as raptors is nontraditional and might be controversial. Therefore, further information regarding the evolution, taxonomy, morphology, and ecology of these birds will clarify the validity of their consideration as raptors. Here we present a review of the published information on seriemas, and discuss future research for these newly adopted raptors. To conduct our review, we developed a systematic map and searched all databases available within Clarivate Analytics' Web of Science, performed a keyword search of Google Scholar, and included the corresponding bibliographies from the Birds of the World website. We reviewed 98 studies, and found that the Red-legged Seriema was the subject of more studies than the Black-legged Seriema. Overall, Brazil and Argentina were the site of most studies. The majority of studies examined physiology (48), followed by behavior (37), threats to the survival of these species (36), and demography (27), while smaller numbers of studies examined stressors (e.g., habitat changes, causes of mortality and injury such as predation, hunting, etc.) (20), and conservation actions (10). Patterns of study categorizations were similar for both species, and the distribution of studies across months was also fairly even for both species. This is the first study to systematically review and assess the published information on seriemas. Our results show the topics and locations on which past studies have focused, and highlight potentially fruitful avenues for future research. Although threats to seriemas have been identified, these have not been thoroughly assessed; thus, their extent and effects on seriema populations were difficult to ascertain. Future research should focus on testing existing hypotheses regarding seriema feeding, vocalization, social, and territorial behaviors, while documenting natural history. Researchers should build on past investigations while establishing programs to monitor the conservation status of seriemas across their ranges.