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At least 181 records · Page 10Linked to original sources
USGS2006

Effects of methyl mercury on reproduction in American kestrels

Methyl mercury (MeHg) readily passes through biological membranes, accumulates in individuals, and biomagnifies in higher order predators. It is acutely toxic to some birds at 5-15 parts per million (ppm) wet weight in the diet, and it can damage the central nervous system, impair reproduction, and retard growth and development. The effects of MeHg on reproduction in wild raptors are poorly known, and experiments with captive raptors have not included measures of reproductive response. In this study, breeding pairs of captive American kestrels (Falco sparverius) were exposed to environmentally realistic concentrations of MeHg in the diet and their subsequent reproduction was measured. Egg production, incubation performance, and the number of eggs hatched markedly decreased between 3.2 and 4.6 ppm MeHg dry weight in the diet. The percent of eggs hatched declined between 0.75 and 2 ppm MeHg dry weight in the diet and further declined to almost total hatching failure between 3.2 and 4.6 ppm. The number of fledglings and the percent of nestlings fledged were greatly reduced at 0.75 ppm MeHg dry weight in the diet and began a final sharp decline between 2 and 3.2 ppm. Dietary concentrations of > 4.6 ppm MeHg dry weight were associated with total fledging failure. Mercury concentrations in a set of 19 `second-laid? eggs collected from all groups were related to dietary concentrations of MeHg and the reproductive responses of kestrels in each group. Observed percentage declines in fledgling production caused by diets containing >2 ppm MeHg dry weight would result in the production of insufficient numbers of young kestrels for maintenance of wild populations. Concentrations of total Hg in eggs from the highest diet group (5.9 ppm dry weight) were higher than egg concentrations reported for either wild birds or for captive birds fed dry commercial food containing 5 ppm MeHg wet weight.

Book chapter↗
USGS2007

Sublethal responses of avian embryos exposed to polybrominated diphenyl ether flame retardants

Polybrominated diphenyl ethers PBDEs) have been detected in bird eggs worldwide, and despite increasing concentrations over the past 25 years, toxicological thresholds have yet to be established. We previously reported embryonic survival, and pipping and hatching success in chicken (Gallus gallus), mallard (Anas platyrhynchos) and American kestrel (Falco sparverius) embryos receiving 0.01-20 :g PBDE/g egg. Survival, pipping and hatching success were decreased in kestrels, suggesting that they are more sensitive to PBDEs than chickens and mallards. Adverse effects were detected in kestrels at levels (> 1 :g/g egg) believed to approach environmentally relevant PBDE concentrations. Polychlorinated biphenyl congener 126 (PCB 126) was used as a positive control (1000 pg/g egg) in this study, and survival endpoints in chicken and kestrel were decreased at this dose. Some PBDE and PCB congeners are structurally similar to thyroid hormones and have been demonstrated to affect thyroid homeostasis in laboratory rodents. In the present study, thyroid glands collected from day old hatchling chickens, mallards, and kestrels and were analyzed for thryoxine (T4) using a solid phase radioimmunoassay (DPC, Inc.) specifically validated for each of these species. Results indicated that thyroid gland T4 stores (total gland content and T4 /mg thyroid) in these species were relatively consistent and not significantly affected by PBDE exposure. In contrast, glandular T4 stores were significantly lower (P < 0.01) in PCB 126 treated kestrels. Decreases in circulating T4 levels in response to contaminants (e.g., PCBs, ammonium perchlorate) may lead to greater release of glandular T4 to maintain a euthyroid state, which could decrease thyroidal T4 stores. While PBDEs have been suggested to influence circulating T4 in kestrel fledglings (Fernie et al., 2005), it appears that glandular T4 was not affected in chicken, mallard or kestrel hatchlings exposed in ovo. Histopathological changes in liver, kidney and immune organs, bone length, and potential skeletal deformities are currently being examined.

Book chapter↗
USGS1982

Measurements of fall migrant peregrine falcons from Texas and New Jersey

Three subspecies of Peregrine Falcons (Falco peregrinus) breed in North America: F. p. anatum, formerly bred in all eco-geographic regions of North America south of the Arctic tundra, except for the immediate vicinity of the northwest Pacific Coast; F. p. tundrius breeds in the Arctic tundra; and F. p. pealei, a relatively sedentary form, occupies the region of the northwest Pacific coast excluded from the range of F. p. anatum (Fyfe et al. 1976). Compared with tundrius, anatum is larger and darker, and the white auricular area is less extensive in proportion to the black malar stripe (White 1968a). This paper presents morphological information from two migrant populations. Also, measurements are compared with F. p. tundrius described by White (1968a,b), although shrinkage in study skins (the source of White's measurements) was recently documented (Fjelds• 1980) and confounds direct comparison.

Texas, New Jersey↗
USGS2000

Seventeenth breeding-bird census. 34. Diked wet meadow

Several characteristics of plumage, including color and molt schedule, are influenced by hormonal signals, and hence may be modified by endocrine active contaminants. If so, the functions of plumage (e.g. communication for mating or territorial defense), may be compromised by exposure to such compounds. Polychlorinated biphenyls (PCBs) are ubiquitous and persistent environmental toxins that can disrupt endocrine function in laboratory animals. Captive American kestrels (Falco sparverius) were fed PCBs (Aroclor 1242) at 6 and 60 ppm, thyroxine at 10 ppm, estradiol at 1.4 ppm, and a thyroid hormone blocker (propylthiouracil: PTU) at 2000 ppm, mixed in their normal diet. Plumage characteristics measured included: the width of the black subterminal band on the tail, brightness (a composite index of hue and saturation), reflectance from 230 - 800 nm (measured on a reflectance spectrophotometer), the pattern of feather loss and regrowth on the tail and wing, and the timing of onset and the duration of molt. PCB-treated birds did not differ from controls, but birds treated with thyroxine were significantly different from those dosed with estradiol or PTU in the width of subterminal tail bands, reflectance, and duration of molt. Thus, although hormone treatments did modify some of the plumage characteristics we measured, PCB treatments at these exposure levels did not.

Society of Environmental Toxicology and Chemistry,↗
USGS1984

Heptachlor seed treatment contaminates hawks, owls, and eagles of Columbia Basin, Oregon

We evaluated organochlorine residues in 12 species of hawks. owls, and eagles from the Columbia Basin of Oregon between 1978 and 1981. Companion studies showed that heptachlor epoxide (HE) induced adult mortality and reduced productivity of the Canada Goose (Branta canadensis) and American Kestrel (Falco sparverius).ln this study, brain tissue from raptors found dead and sample eggs from 90 nests were analyzed for organochlorines. The primary concern was HE that entered raptor food chains through the ingestion of heptachlor-treated seed by their prey. HE residues were detected in eggs from 9 of 10 species and ranged as high as 4.75 ppm (wet wt), but no definite effects of HE on productivity were readily apparent from the limited series of nests. However, the hazard of heptachlor seed treatments to birds of prey was demonstrated by the occurrence of lethal residues of HE in brain tissue of 3 Golden Eagles (Aquila chrysaetos) and 1 Rough-legged Hawk (Buteo lagopus). Other organochlorine pesticides were present in the eggs and significant relationships were found between DDE and eggshell thickness for the Swainson's Hawk (Buteo swainsoni) and Western Screech-Owl (Otus kennicotti), although shell thinning (9.6% and 7.4%) was below the generally accepted range where reproductive problems have been known to occur.

Raptor Research↗
USGS1990

Evidence for a fall raptor migration pathway across the South China Sea

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 and were making extensive use of the ship for perching, roosting, and hunting.

Journal of Raptor Research↗
USGS1995

Preliminary raptor surveys in western Mongolia

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 exists. Raptor work in the interior must be supported by four-wheel drive vehicles traveling cross country. Food and fuel for a research team are difficult to procure, but raptor populations are largely unexploited. Raptors frequently nest on the ground or on very low cliffs and tress, and often nest in close proximity of pairs of their own and other species. Several areas of special significance to raptors are discussed including the Taleen Ulaan (Red Steppe) areas of granite dells which we recommend for status as an international reserve.

Journal of Raptor Research↗
USGS1994

Partial migration and wintering localities of American kestrels nesting in the Pacific northwest

Based on banding recoveries, an estimated 89.5% of American kestrels (Falco sparverius) nesting in eastern Oregon, eastern Washington, and Idaho (excluding the Snake River Plain) are migratory and primarily migrate to western Mexico for the winter. Band recoveries from Mexico may be biased; however, we do not know whether the bias is toward more or fewer recoveries. The banding data imply that the remaining kestrels from the region (10.5%) are permanent residents, and we found 2.8% of a northeastern Oregon population on nesting territories in January 1981 (permanent residents). A higher percentage of the nesting population appears to be permanent residents in the valleys along the Snake River Plain than in the remainder of Idaho, eastern Oregon, and eastern Washington (p = 0.02). Limited evidence shows that permanent resident kestrels in eastern Oregon nest earlier than migrants. Information available for the population west of the Cascade Mountains in Oregon and Washington was limited.

Northwestern Naturalist↗
USGS1993

Cryopreservation of American kestrel semen with dimethylsulfoxide

Semen samples from 15 male American Kestrels (Falco sparverius) were frozen in dimethyl sulfoxide (DMSO). The semen was thawed 1-14 mo later and used to inseminate six females during three breeding seasons. Kestrels inseminated with thawed semen containing 4% DMSO produced only infertile eggs (N = 14). Kestrels inseminated with thawed semen containing 6%, 8%, or 10% DMSO produced fertile eggs (N = 14) and live chicks (N = 6). Progressive motility of spermatozoa in thawed semen containing 10% DMSO was less (44 ? 6%) than in thawed semen containing 6% (62 ? 10%) or 8% (61 ? 1%) DMSO.

Journal of Raptor Research↗
USGS1992

Distribution and color variation of gyrfalcons in Russia

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 the southernmost extension. Because the northernmost portions of the species' range in continental Russia are in central Siberia where white variants were rare, we propose that a better predictor of the white variant is longitude, not latitude. White birds were most frequent at the eastern reaches of both the Palearctic and Nearctic. The best environmental correlates of this distribution pattern may be the southward bending thermal isoclines proceeding eastward toward Greenland or Kamchatka, where both land masses are bathed by cold oceanic currents of Arctic origin. By contrast, the western reaches of both land masses are bathed by warm currents. In these western reaches, Gyrfalcon summer distribution is displaced northward and dark variants predominate. The breeding range of the Gyrfalcon, determined by mapping the locations of the specimens we examined, differs little from the range proposed in 1951.

Journal of Raptor Research↗
USGS1993

Use of satellite telemetry for study of a gyrfalcon in Greenland

Long-term research in Greenland has yielded 1 8 years of incidental sightings and 2 years of surveys and observations of gyrfalcons(Falco rusticolus) around Sondrestromfjord, Greenland. Gyrfalcons nest on cliffs along fjords and near rivers and lakes throughout our 2590 sq. km study area. Nestlings are present mid-June to July. In 1990, we marked one adult female gyrfalcon with a 65 g radio-transmitter to obtain location estimates via the ARGOS polar orbiting satellite system. The unit transmitted 8 hours/day every two days. We obtained 145 locations during 5 weeks of the nestling and fledgling stage of breeding. We collected 1-9 locations/day, with a mean of 4/day. We calculated home range estimates based on the Minimum Convex Polygon( MCP) and Harmonic Mean (HM methods and tested subsets of the data based on location quality and number of transmission hours per day. Home range estimated by MCP using higher quality locations was approximately 589 sq. km. Home range estimates were larger when lower-quality locations were included in the estimates. Estimates based on data collected for 4 hours/day were similar to those for 8 hours/day. In the future, it might be possible to extend battery life of the transmitters by reducing the number of transmission hours/day. A longer-lived transmitter could provide information on movements and home ranges throughout the year.

Journal of Raptor Research↗
USGS1999

Trash-caused mortality in Mongolian raptors

On four expeditions (1994, 1995, 1997, and 1998) through Mongolia, we found two kinds of mortality associated with trash gathered by parent raptors as part of the nest building process. Our observations of actual mortality were limited to three species: the golden eagle (Aquila chrysaetos) (2 clutches of eggs), the saker falcon (Falco cherrug) (4 nestlings), and the upland buzzard (Buteo hemilasius) (1 nestling); all from the eastern half of Mongolia.

Ambio↗
USGS1984

Acute responses of American kestrels to methyl parathion and fenvalerate

Physiological and toxicological effects of p.o, methyl parathion (0.375-3.0 mg/kg) or fenvalerate (1000-4000 mg/kg) were examined over a 10 h period in American kestrels (Falco sparverius) maintained in thermoneutral (22?.C) and cold (-5?.C) environments. Methyl parathion was highly toxic (LD50=3.08 mg/kg, 95% confidence limits=2.29-4.l4 mg/kg, producing overt intoxication (abnormal posture, ataxia, paresis), dose-dependent inhibition (26-67%) of brain acetylcholinesterase activity, hyperglycemia, and elevated plasma corticosterone concentration. Transient but pronounced hypothermia was associated with plasma cholinesterase inhibition in excess of 50% (2 h after intubation), although this response was highly variable (plasma ChE inhibition vs. A cloacal temperature, r=-0.60). Fenvalerate, at doses far exceeding those encountered in the environment, caused mild intoxication (irregular head movement) and elevated plasma alanine aminotransferase activity, but did not alter cloacal temperature, plasma activities of CK, U-HBDH, and LDK, or concentrations of corticosterone, glucose, triiodothyronine, and uric acid. Cold exposure intensified methyl parathion toxicity, but did not affect that of fenvalerate. It would thus appear that the organophosphorus insecticide methyl parathion poses far greater hazard than the pyrethroid fenvalerate to raptorial birds.

Federation Proceedings↗
USGS2000

Seventeenth breeding-bird census. 34. Diked wet meadow

Several characteristics of plumage, including color and molt schedule, are influenced by hormonal signals, and hence may be modified by endocrine active contaminants. If so, the functions of plumage (e.g. communication for mating or territorial defense), may be compromised by exposure to such compounds. Polychlorinated biphenyls (PCBs) are ubiquitous and persistent environmental toxins that can disrupt endocrine function in laboratory animals. Captive American kestrels (Falco sparverius) were fed PCBs (Aroclor 1242) at 6 and 60 ppm, thyroxine at 10 ppm, estradiol at 1.4 ppm, and a thyroid hormone blocker (propylthiouracil: PTU) at 2000 ppm, mixed in their normal diet. Plumage characteristics measured included: the width of the black subterminal band on the tail, brightness (a composite index of hue and saturation), reflectance from 230 - 800 nm (measured on a reflectance spectrophotometer), the pattern of feather loss and regrowth on the tail and wing, and the timing of onset and the duration of molt. PCB-treated birds did not differ from controls, but birds treated with thyroxine were significantly different from those dosed with estradiol or PTU in the width of subterminal tail bands, reflectance, and duration of molt. Thus, although hormone treatments did modify some of the plumage characteristics we measured, PCB treatments at these exposure levels did not.

Society of Environmental Toxicology and Chemistry,↗
USGS2002

Schizochromism in a Peregrine Falcon from Arizona

Herein, we report the first record of schizochromism in the Peregrine Falcon (Falco peregrinus). Our example is a nestling from southern Arizona. The lack of dark brown pigment in this bird made it closely resemble the blue-gray plumage of an adult. Near fledging time, the bird was eaten by its nestmates, so this article also documents cannibalism.

Journal of Raptor Research↗
USGS1985

The austral peregrine falcon: Color variation, productivity, and pesticides

The austral peregrine falcon (Falco peregrinus cassini) was studied in the Andean foot- hills and across the Patagonian steppe from November to December 1981. The birds under study (18 pairs) were reproducing at or near normal (pre-DDT) levels for other races. Pesticide residues, while elevated, were well below the values associated with reproductive failure in other populations. With one exception, eggshells were not abnormally thin. The peregrine falcon in Patagonia exhibits extreme color variation. Pallid birds are nearly pure white below (light cream as juveniles), whereas normally pigmented birds are black-crowned and conspicuously barred with black ventrally. Rare individuals of the Normal Phase display black heads, broad black ventral barring, and warm reddish-brown ventral background coloration.

National Geographic Research↗
USGS2009

Species differences in the sensitivity of avian embryos to methylmercury

We injected doses of methylmercury into the air cells of eggs of 26 species of birds and examined the dose-response curves of embryo survival. For 23 species we had adequate data to calculate the median lethal concentration (LC50). Based on the dose-response curves and LC50s, we ranked species according to their sensitivity to injected methylmercury. Although the previously published embryotoxic threshold of mercury in game farm mallards (Anas platyrhynchos) has been used as a default value to protect wild species of birds, we found that, relative to other species, mallard embryos are not very sensitive to injected methylmercury; their LC50 was 1.79 ug/g mercury on a wet-weight basis. Other species we categorized as also exhibiting relatively low sensitivity to injected methylmercury (their LC50s were 1 ug/g mercury or higher) were the hooded merganser (Lophodytes cucullatus), lesser scaup (Aythya affinis), Canada goose (Branta canadensis), double-crested cormorant (Phalacrocorax auritus), and laughing gull (Larus atricilla). Species we categorized as having medium sensitivity (their LC50s were greater than 0.25 ug/g mercury but less than 1 ug/g mercury) were the clapper rail (Rallus longirostris), sandhill crane (Grus canadensis), ring-necked pheasant (Phasianus colchicus), chicken (Gallus gallus), common grackle (Quiscalus quiscula), tree swallow (Tachycineta bicolor), herring gull (Larus argentatus), common tern (S terna hirundo), royal tern (Sterna maxima), Caspian tern (Sterna caspia), great egret (Ardea alba), brown pelican (Pelecanus occidentalis), and anhinga (Anhinga anhinga). Species we categorized as exhibiting high sensitivity (their LC50s were less than 0.25 ug/g mercury) were the American kestrel (Falco sparverius), osprey (Pandion haliaetus), white ibis (Eudocimus albus), snowy egret (Egretta thula), and tri-colored heron (Egretta tricolor). For mallards, chickens, and ring-necked pheasants (all species for which we could compare the toxicity of our injected methylmercury with that of published reports where methylmercury was fed to breeding adults and was deposited into the egg by the mother), we found the injected mercury to be more toxic than the same amount of mercury deposited naturally by the mother. The rank order of sensitivity of these same three species to methylmercury was, however, the same whether the methylmercury was injected or maternally deposited in the egg (i.e., the ring-necked pheasant was more sensitive than the chicken, which was more sensitive than the mallard). It is important to note that the dose-response curves and LC50s derived from our egg injections are useful for ranking the sensitivities of various species but are not identical to the LC50s that would be observed if the mother bird had put the same concentrations of mercury into her eggs; the LC50s of maternally deposited methylmercury would be higher.

Archives of Environmental Contamination and Toxico↗
USGS1986

DDE, DDT + dieldrin: Residues in American kestrels and relations to reproduction

Captive American kestrels (Falco sparverius) given long-term dietary dosages of DDT and dieldrin in combination, at low and high rates, were compared with controls to determine the effects of the toxicants on reproductive success and eggshell thickness. Additional kestrels were dosed with DDE to determine its effect on shell thickness. Tissues of birds that died or were sacrificed, and eggs, were analyzed for DDE, DDD, DDT, and dieldrin. Eight paired birds, mostly males, given a high dosage of DDT + dieldrin died of dieldrin poisoning. Three periods of heavy mortality involving only dosed birds, which occurred in summer 1966, fall 1967, and spring 1968, followed temperature declines and other stress factors. Organochlorine concentrations in tissues of sacrificed birds and eggs in all units of the DDT + dieldrin study were significantly different among treatments. Residue concentrations in tissues of birds on high dosage of DDT + dieldrin were about 3 times higher than those on low dosage, a difference similar to the relative magnitude of the dose rates. Concentrations of some toxicants, especially DDE, were significantly higher in tissues of males than females, although these differences were difficult to interpret because males generally were sacrificed later than females. Concentrations in tissues and eggs of dosed yearlings, placed on clean food 7 to 9 weeks before pairing, were often significantly lower than in those yearlings that remained on dosage. Concentrations of each toxicant were usually highly correlated (r > 0.85) among tissues, especially for DDE and dieldrin. Organochlorine concentrations in brains and eggs could be predicted from concentrations in carcasses. DDE and dieldrin concentrations in eggs were about one-half those in carcasses, DDD about one-seventh, and DDT 1.5 to 2 times higher in eggs than carcasses. Eggshells of DDT + dieldrin-dosed kestrels were 6-23% thinner than eggshells of corresponding controls in different groups and years. Organochlorine concentrations in eggs and tissues of females were poorly correlated with shell thickness. Of the four toxicants in eggs, DDE was significantly and most closely correlated with fledging success. Interpretation of direct comparisons between our DDT + dieldrin studies and most current field situations are difficult because contaminant profiles in our birds are unlike those in most field samples.

Fish and Wildlife Technical Report↗