Filters: Tags: Journal of Raptor Research (X) > partyWithName: D.H. Ellis (X)
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Four manufacturers now produce transmitters in the size range suitable for raptors (3-5% of body mass). Dummies of these transmitters will be displayed and harnessing techniques will be demonstrated. Estimates will be given for: cost, reliability, longevity, mass, availability, programmability, power output and other information essential in deciding on manufacturer and model.
Gyrfalcon (Falco rusticolus) museum specimens in Moscow (73) and St. Petersburg (132) were divided into four color classes (gray, light gray, white gray, and white) and four longitudinal belts representing major physiographic regions of northern Russia. Gray variants predominated in the west and central regions. White birds were most common in extreme eastern Siberia, but were occasionally found even west of the Ural Mountains. Frequencies were as follows: European Russia 4% white, 50% gray (the remainder were intermediates); western Siberia 0% white, 58% gray; central Siberia 15% white, 42% gray; and eastern Siberia 47% white, 33% gray. Remarkably, in the easternmost subregion, white birds predominated even near...
Raptors were observed on a 5200 km expedition from Ulaan Baatar through the Hangay Mountains to the Russian Altay Mountains with return through the Gobi Altay Mountains. The focus of the expedition was on nesting ecology of the Saker (Falco cherrug) and Altay falcons (F. altaicus) (25 eyries were located), but nests were also found for seven other species including more than 30 nests found of the upland buzzard (Buteo hemilasius). We conducted 21 day-long counts and 10 more formal raptor road counts. Raptors were concentrated in areas where perches were common and where food was most abundant. Western Mongolia remains a vast undeveloped land where camel trains and yak carts are normal. No developed highway network...
Twenty-six (23 traveling and three point) raptor roadside surveys were conducted during a 29,000 km expedition through nine nations of South America. During roadside surveys, we tallied 41 of the 87 (47%) diurnal raptor species (including vultures) that occur in South America. The number of species observed per route varied from 17 in the wet savanna of Venezuela to only two species recorded in the harsh Atacama Desert and the dry montane grasslands of Chile and Peru. Raptor density (non-vultures) varied from 1 per 67 km in the Atacama Desert to more than 1 per km in agricultural areas where caracaras and other species that utilize disturbed habitats were common. Responses of raptor communities to deforestation...
The Altar Valley in southcentral Arizona was once a iallgrass prairie. Overgrazing prevented fire and spread mesquite, allowing the area, now a savanna, to be heavily used by tree-nesting raptors in summer and heavily hunted by perch-hunting raptors in winter. The breeding raptor community (over 150 pairs) consists primarily of red-tailed hawks (Buteo jamaicensis), great horned owls (Bubo virginianus), and Swainson's hawks (Buteo swainsoni). Common ravens (Corvus corax) are also common and there is a recently discovered small population of black-shouldered kites (Elanus caeruleus). Recent efforts to restore the endangered masked bobwhite (Colinus virginianus) to the area clash with habitat needs of the raptors....
The rain forest of the Sierra Imataca in eastern Venezuela has been subjected to extensive deforestation for pastures and agricultural settlements. In the last decade the opening of access roads combined with intensified logging and mining activities have fragmented a significant portion of the remaining forest. We noted local distribution and habitat use for 40 species of diurnal raptors observed in ten affected areas, including raptors considered as forest interior species and some open country species utilizing the man-made openings inside the forest for roosting and foraging.
There are few published records of antlers in golden eagle (Aquila chrysaetos) nests. This note reports extensive use of caribou (Rangifer tarandus) antlers in three golden eagle nests in the Cape Kruzenstern region of northwestern Alaska. The importance of antlers to this population of eagles can be explained at least in part by (1) the lack of suitable woody vegetation on the open tundra, (2) the similarity of antlers to sticks, and (3) the abundance of antlers, especially cow caribou antlers, in the region.
While conducting seabird surveys along the cruise track of the Soviet oceanographic Research Vessel Akademlk Korolev in the South China Sea in late October, 1988, we encountered about 150 land birds, including about 40 raptors. Most of the raptors were small accipiters, but we also recorded small numbers of Peregrine Falcons (Falco peregrinus) and Oriental Scops Owls (Otus sunia). We saw most of the raptors during a 3-day period in a restricted area ca 350 km southeast of the southern tip of the Indo-China Peninsula. The observations suggest that a significant raptor migration corridor exists between Viet Nam and Borneo. The behavior and body condition of the diurnal raptors suggest that they were in good health...
During 1994, 1995, 1997, and 1998 expeditions across Mongolia, we located over 250 upland buzzard (Buteo hemilasius) nests. At these, we noted considerable morphological variation in plumage coloration and in leg pterylosis. In 1997 and 1998, we examined 131 nests scattered across eastern and central Mongolia and report here the tarsal condition of 119 nestlings from 59 broods where young were at least 2 weeks of age. Of 119 birds carefully examined, 50 (42%) had less than fully feathered tarsi and 4 of the 69 with fully feathered tarsi had scattered feathers on their toes. Thus, 54 of 119 birds (45%) in some way deviated from the feathered tarsibare toes condition. This extraordinary degree of variability in feather...
For this study, I compared sequentially molted feathers for a few captive raptors from year to year and symmetrically matched feathers (left/right pairs) for many raptors to see if color patterns of sequential feather pairs were identical or if symmetrical pairs were mirror-image identical. Feather pairs were found to be identical only when without color pattern (e.g., the all-white rectrices of Bald Eagles [Haliaeetus leucocephalus]). Complex patterns were not closely matched, but some simple patterns were sometimes closely matched, although not identical. Previous claims that complex color patterns in feather pairs are fingerprint-identical (and therefore that molted feathers from wild raptors can be used to identify...
From surveys in many countries, we report raptors using unusual nesting materials (e.g., paper money, rags, metal, antlers, and large bones) and unusual nesting situations. For example, we documented nests of Steppe Eagles Aquila nipalensis and Upland Buzzards Buteo hemilasius on the ground beside well-traveled roads, Saker Falcon Falco cherrug eyries in attics and a cistern, and Osprey Pandion haliaetus nests on the masts of boats and on a suspended automobile. Other records include a Golden Eagle A. chrysaetos nest 7.0 m in height, believed to be the tallest nest ever described, and, for the same species, we report nesting in rudimentary nests. Some nest sites are within a few meters of known predators or competitors....
Continental records point to shooting, removal of young and destruction of nests as the primary conservation problems for harpy eagles (Harpia harpyja); bird-observer visits are a new source of concern. Nesting events are roughly 3 yr apart. Nests are used during and after intensive manipulation of the surrounding habitat, and minimum distance between active sites was 3-5 km. In nine nesting sites along a 100-km stretch of the Imalaca Mountains in Venezuela, we fitted five fledglings with satellite-tracked tags from NASA. One of these birds was hacked with the help of the loggers who destroyed its nest. All these nests were active while logging ensued. Out of three renesting attempts, one failed when the nest collapsed....
The Peregrine Falcon (Falco peregrinus cassini) in Patagonia attracted wide interest two decades ago when there was a focus on determining the taxonomic position of the Pallid Falcon (also called Kleinschmidt's falcon and Tierra del Fuego falcon; formerly named Falco kreyenborgi). In 1981, however, the pallid falcon was confirmed to be a pale color morph of the peregrine, and since that time, little work has been conducted on this color morph. Continent-wide research has continued and has yielded a fair understanding of the breeding distribution of the Peregrine Falcon in South America. Also, two preliminary food habits studies on the peregrine have been completed in Patagonia. Together those papers provided a list...
Monitoring animal movements by satellite was first ac complished in 1970 with an elk in Wyoming. The large size of early transmitter packages restricted their use to very large animals. Miniaturization of electronic components in the 1980s allowed application of satellite telemetry to large birds. Satellite transmitters have been tested with mixed results on geese, swans, petrels, bustards, eagles, and falcons. Dramatic weight reduction in the 1980s was quickly followed by tests of a variety of transmitter shapes on captive birds. Research on attachment methods helped in selecting those methods least likely to elicit adverse behavior. Wind tunnel experiments were conducted to produce more aerodynamically efficient...
We observed two incidents of novel social behavior in the saker falcon (Falco cherrug) in Mongolia. First, we provide an account of a two-week-old saker falcon chick killing its nest mate, the first direct observation of siblicide in the genus Falco. We also report aerial combat between three adult saker falcons including observations of talon grappling, whirling, and Splayed-toes-flight, a previously undescribed social display.
The striking black and white plumage of the juvenile Golden Eagle (Aquila chrysaetos) provides an excellent opportunity to examine the possible selective forces influencing the strategic placement of dark pigment in birds. The conflict between opposing selective pressures (first, toward large white patches, which may allay aggression in adults, and second, toward dark plumage to promote camouflage and limit solar and abrasive wear) provides the stage whereon are revealed a score of pigmentation traits of potential adaptive value. The general pigmentation trend is for zones that are more exposed to the sun to be darker than elsewhere. More specifically: (1) for rectrices and remiges, outer webs are darker than inner;...
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