Determining a species' geographic range is important for conservation planning, yet this information is lacking for many raptors. In rapidly changing environments, defining current and predicting future distributions can help define priority areas for monitoring and research. The Laggar Falcon (Falco jugger) is a rare and understudied raptor resident across the Indian subcontinent, categorized as Near Threatened, with populations potentially in rapid decline. Using a Species Distribution Modelling framework we update current distribution and predict future distribution based on two future climate change scenarios for 2050. Our current distribution model had high predictive accuracy, and defined core areas of high climatic suitability in western India and southeastern Pakistan. Three bioclimatic variables contributed 79.9% to model prediction: mean temperature of the wettest quarter (50.1%), precipitation seasonality (17.6%), and precipitation in the driest month (12.2%). Projecting our model into climate change scenarios for 2050 resulted in up to 6% mean gain in suitable climate space for a lower emission scenario, but a 5% mean loss in suitable climate by 2050 in a high emissions scenario. All future predictive models showed similar multidirectional range movements within the current predicted core range. Based on these results, Laggar Falcon distribution may not be adversely affected by climate change. We recommend directed population surveys and monitoring based on current model predictions of areas of highest climate suitability, which are likely where Laggar Falcons will persist into the near future. Regular monitoring and research will enhance our knowledge for this raptor, while contributing further data to improve our model predictions.

During seven expeditions across Mongolia, we found 40 Golden Eagle (Aquila chrysaetos) breeding territories with eggs or young. At 20 other locations, we either found old eagle nests with Golden Eagle feathers or saw adult eagles but found no eggs or young. Golden Eagles nested in all but the driest portions of the Gobi Desert and the easternmost grasslands. Nearly all pairs had alternate nests. Of 53 nests used, 60% were on cliff ledges as is typical around the world. However, 19% were on the ground or at other sites that were easily accessible to canid predators, with the most vulnerable nests small and seldom or never reused. The most unusual nests included one atop a conical basalt peak, one on relatively flat ground among tall boulders, four on steep hillsides, one on almost flat ground amid rocky protrusions, and three on cliff tops. Where tall cliffs with many ledges were available, the eagles nested at least 7 m above the ground. Nest construction materials were often unusual and included trash, patches of large mammal hides, paper money, and clothing.

From nearly 600 prey remains collected in 95 nest visits from extreme eastern to extreme western Mongolia, we found that Golden Eagles (Aquila chrysaetos) consumed a high percentage (20%) of predatory birds and mammals. The prey delivered to nests was also very diverse. As expected, the eagles preyed on hares (Lepus tolai, 12%) and marmots (Marmota spp., 38%), but 15% of their prey were foxes (Vulpes spp.). We identified 30 species of birds, including six species of raptors, among the prey remains. Surprisingly, ground squirrels (Spermophilus spp., 5%) were underrepresented and even in vole (Lasiopodomys and kin) irruption years/zones, voles and other small rodents (4%) were seldom found in the nests. Loss of rodents and other prey due to aerial broadcasting of rodenticides likely affects Golden Eagles in Mongolia, as do persecution, mortality from electrocution, and removal of eagles for falconry and tourist trade. All these need careful quantification.

We used observation data from major hawk-watch sites in northeastern North America to assess multiyear cycles in breeding productivity of the Northern Harrier (Circus hudsonius). We found that autumn totals of migrating harriers for 1983–2017 autocorrelated positively at the 4-yr lag for interior, but not Atlantic coastal, counts. The autocorrelation was especially high for harriers counted in October. The autumn counts of south-bound harriers were not correlated with counts of north-bound harriers in the previous spring. Interannual differences in atmospheric circulation during migration in 1983–2017, as expressed by the autumn North Atlantic Oscillation Index, correlated with the autumn harrier counts but did not have a 4-yr cycle. The temporal pattern revealed in this study should be considered when using counts of autumn migrants to infer regional population trends. Future research could focus on the cause of the cyclic pattern in harrier numbers. One obvious question concerns the relationship between spring populations of meadow voles (Microtus pennsylvanicus), which are important prey for harriers during breeding, and harrier numbers reported during the subsequent autumn migration.

We used a two-step process to determine region of geographic origin for migratory Red-tailed Hawks (Buteo jamaicensis) and Cooper's Hawks (Accipiter cooperii). First, we used encounter data from the USGS Bird Banding Laboratory to estimate natal dispersal distances of Red-tailed Hawks and Cooper's Hawks. Then we used this information to assess whether hawks banded at migration stations and later encountered as breeding birds could be assigned to an approximate region of origin. Across the USA, the average apparent natal dispersal distance of Red-tailed Hawks was 137 ± 287 km (n = 127, median = 23 km) and of Cooper's Hawks was 40 ± 90 km (n = 70, median = 13.5 km). There were no differences in apparent natal dispersal as a function of latitude or longitude across the continent. From data on birds banded at migration stations and then encountered later as likely breeders, we inferred that these encounter locations will, on average, reflect these birds' region of origin. Because individuals of these two species tend to have short natal dispersal distances, we can infer regions of origin from breeding-season encounters of banded individuals originally trapped at migration sites across North America. As an example, we used data from migrating Red-tailed and Cooper's Hawks trapped in the Marin Headlands, California, that were later encountered as likely breeders to assign the region of origin of these individuals. Using this information, we inferred that early-migration-season Red-tailed Hawks originated in central California and that later-migration-season Red-tailed Hawks were a mix of individuals originating from central California and eastern Oregon. Cooper's Hawks captured during migration at Marin originated west of the Cascade and Sierra Nevada Mountains, including areas in northern California, Oregon, and British Columbia. Encounter data for hawks banded during migration then captured later during the breeding season may help migration researchers better understand origins of birds captured at migration sites and better link population trends at migration stations with population trends of breeding birds.

Effective individual identification is important in many aspects of animal studies. Leg bands and wing tags are commonly used to mark individual birds in the field; however, for nocturnal or cryptic birds it is difficult to directly observe individual tags due to darkness or dense vegetation. Alternatively, some studies suggest that many birds have individually distinctive vocalizations, and these differences could be used to identify individuals. Here we assessed the possibility of identifying individual Ural Owls (Strix uralensis) based on their defensive territorial hooting calls. During breeding season, we recorded hooting calls of 15 males in 2018 and of 16 males in 2019 respectively at the Dagangzi national forest in northeastern China. We measured 19 variables for each call. Using forward stepwise discriminant function analysis, we correctly classified 92.8% of the calls of individuals in 2018 and 93.9% in 2019, based on leave-one-out cross validation. The most important discriminating variables included duration of the interval between the first and second notes, duration of the interval between the second and third notes, the third note duration, and the number of “humps” (upward projections in a note in the sound spectrogram) in the first note. The calls of individuals remained stable both within a breeding season and between years. Our results suggest that territorial calls are effective for identifying male Ural Owl individuals, and this technique could contribute to population surveys and long-term monitoring.

We studied the ectoparasitics of breeding Lesser Kestrels (Falco naumanni) in Mongolia. We captured 20 adult, one fledgling, and 11 nestling Lesser Kestrels and examined them for ectoparasites in Ikh Nart Nature Reserve, a semi-desert region of Mongolia. We examined 11 nestlings multiple times throughout the nestling period to count carnid flies (Carnus hemapterus). All nestlings age 1–4 d old were infested (mean of 6.0 flies per nestling). Older nestlings had fewer carnid flies over the course of the nesting season. We also collected 120 louse flies (Ornithophila gestroi) from 20 adults and one fledgling, an infestation rate of 85.7%. The mean number of louse flies per host was 6.3 (range = 1–19) per infested bird. These represent the first Mongolian records of O. gestroi and C. hemapterus from adult and nestling Lesser Kestrels. These two fly species have been previously recorded from several diverse avian species in many regions of Eurasia and North America. The paucity of investigations of raptor ectoparasites in Mongolia suggests that this is an important area for future research and that additional reports of other ectoparasites are likely to be forthcoming.

Natural intergeneric hybridization occurs rarely in raptors. In 2012, L. Hug observed a juvenile hawk interacting with a banded adult Common Black Hawk (Buteogallus anthracinus) in Sonoma County, California, USA, and reported that the juvenile was a Common Black Hawk × Red-shouldered Hawk (Buteo lineatus) hybrid (Hug 2016; Western Birds 47:325–326). A disparity of opinions concerning the parentage of the juvenile prompted us to document the nesting efforts of this Common Black Hawk in 2013 and 2014. The 2013 nesting attempt failed during incubation before the identity of the mate could be confirmed. In 2014 the adult female Common Black Hawk bred with an adult male Red-shouldered Hawk (B. l. elegans), and this pair fledged one hybrid offspring. Evidence of this hybridization included observations of the pair engaged in courtship flights (n = 3), copulations (n = 2), and simultaneous nest attendance (n = 2), and the offspring's intermediate physical characters and vocalizations. Although the hybrid offspring's juvenile plumage more closely resembled a juvenile Common Black Hawk overall, the hybrid also exhibited some intermediate plumage, morphological, and vocal characteristics. This hybridization event appears to be an example of the desperation hypothesis, in which a rare vagrant, unable to secure a conspecific mate, settled on a species of raptor abundant in western California. Dietary overlap of the two parental species (e.g., crayfish, amphibians) and strong associations with aquatic habitats may also have facilitated this pairing and hybridization event.