Salt toxicosis in ruddy ducks that winter on an agricultural evaporation basin in California

Agricultural evaporation basins are used as a means to dispose of highly saline underground-tile-drainage water in the San Joaquin Valley (California, USA). The hypersaline water conditions encourage high aquatic invertebrate production, primarily brine shrimp (Artemia franciscana), which attract birds to these sites. Cool winter temperatures (< 4 C) and hypersaline water conditions (> 70,000 mumhos/cm) resulted in feather salt encrustation and salt toxicosis in ruddy ducks (Oxyura jamaicensis). During December 1998 and January 1999, approximately 200 dead and sick ruddy ducks were collected from an evaporation basin and five healthy control ruddy ducks were collected from a freshwater wetland. Brains contained > or = 1,890 ppm sodium (wet tissue mass) in seven dead birds and contained < or = 1,150 ppm sodium in the control birds. Liver arsenic, lead, and mercury concentrations were < 1 ppm in all birds examined. Manganese, molybdenum, and copper liver concentrations did not differ significantly (P > 0.05) between the two groups of ducks. The dead ducks had significantly higher liver selenium, cadmium, iron, and zinc than the controls, but the concentrations were not sufficient to cause toxicity. Significant gross and microscopic lesions in most of the dead birds included conjunctivitis, lens opacity and cataract formation, vascular congestion in various organs most notably in the meninges of the brain, and myocardial and skeletal muscle degeneration.     

Outbreak of avian polyomavirus infection with high mortality in recently captured Crimson's seedcrackers (Pyrenestes sanguineus)

Avian polyomavirus (APV) infection of recently imported Crimson's seedcrackers (Pyrenestes sanguineus) resulted in mortality in 56 of 70 (80%) birds in January 2000. Viral infection in these birds was characterized by diarrhea, anorexia, and lethargy, and death usually ensued within 48 to 72 hr of initial clinical signs. Bacteriologic testing resulted in consistently negative results. Histologic examination of tissues from dead birds revealed large intranuclear inclusion bodies, which at electron microscopy examination, contained 42- to 49-nm viral particles. The diagnosis of APV infection was based on immunohistochemistry and immunoelectronmicroscopy, using a monoclonal antibody specific for VP-1 major capsidic APV protein. This is the first report of an acute APV outbreak in wild, recently imported, Crimson's seedcrackers.     

Efficacy and persistence of Bacillus sphaericus, Bacillus thuringiensis var. israelensis, and methoprene against Culiseta incidens (Diptera: Culicidae) in tires

The efficacy and persistence of Bacillus sphaericus (2362) was compared at three dosage rates in tires that continually contained cadavers of Culiseta incidens (Thomson) versus tires with all dead larvae removed. At treatment rates of 3.75 and 7.5 ppm, the continual presence of cadavers in the tire water resulted in higher mortality rates. At the 15 ppm treatment rate, mortality rates were similar in tires with or without cadavers. Mortality rates increased in all tires 4-6 wk after treatment, suggesting an amplification of the pathogen. The mortality rate did not exceed 90% for greater than 2 wk in any of the tires. At a second site, the efficacy of B. sphaericus, Bacillus thuringiensis var. israelensis, and methoprene was evaluated against C. incidens in tires exposed to full sunlight versus shaded tires. In shaded tires inoculated with B. sphaericus (15 ppm) and B. thuringiensis var. israelensis (15 ppm), mortality exceeded 90% for 5 and 2 wk, and 50% for 10 and 4 wk, for the two bacteria, respectively. Larvae were adequately controlled (greater than 75% mortality) in the sunny tires for approximately 1 wk. The insect growth regulator, methoprene (applied at 2.5 ppm), inhibited the emergence of approximately 90% of the larvae present at the time of treatment, but not of larvae subsequently introduced into either the sunny or shaded tires.     

Fatal Attraction of Short-Tailed Shearwaters to Artificial Lights

Light pollution is increasing around the world and altering natural nightscapes with potential ecological and evolutionary consequences. A severe ecological perturbation caused by artificial lights is mass mortalities of organisms, including seabird fledglings that are attracted to lights at night on their first flights to the sea. Here, we report on the number of fledging short-tailed shearwaters Ardenna tenuirostris found grounded in evening and morning rescue patrols conducted at Phillip Island, Australia, during a 15-year period (1999–2013). We assessed factors affecting numbers of grounded birds and mortality including date, moon phase, wind direction and speed, number of visitors and holiday periods. We also tested experimentally if birds were attracted to lights by turning the lights off on a section of the road. Of 8871 fledglings found, 39% were dead or dying. This mortality rate was 4–8 times higher than reported elsewhere for other shearwater species, probably because searching for fledglings was part of our systematic rescue effort rather than the opportunistic rescue used elsewhere. Thus, it suggests that light-induced mortality of seabirds is usually underestimated. We rescued more birds (dead and alive) in peak fledging, moonless and windy nights. Mortality increased through the fledging period, in the mornings and with increased traffic on holiday periods. Turning the road lights off decreased the number of grounded birds (dead and alive). While moon, wind and time are uncontrolled natural constraints, we demonstrated that reduction of light pollution and better traffic management can mitigate artificial light-induced mortality.     

Effects of sodium and magnesium sulfate in drinking water on mallard ducklings

One-day-old mallard (Anas platyrhynchos) ducklings were given drinking water for up to 28 days that contained concentrations of sodium and/or magnesium similar to those found in saline wetlands. Growth, tissue development, and biochemical characteristics of these ducklings were compared to those reared on fresh water. Much of the ingested salt was excreted by passage of voluminous fluid excreta. This effect occurred in birds given water with as little as 500 ppm Mg or 1,000 ppm Na. The supraorbital salt gland was active within 4 days in ducklings drinking water containing greater than or equal to 1,500 ppm of Na. Feather growth was decreased in ducklings drinking water with greater than or equal to 1,500 ppm of either Na or Mg. Ducklings drinking water with 3,000 ppm of either ion, or 1,500 ppm of each, grew more slowly than control birds. Ducklings drinking water with 3,000 ppm of either Na or Mg had reduced thymus size and bone breaking strength. Those drinking water with 3,000 ppm of Mg, or 3,100 ppm Na and 1,300 ppm Mg also had less trabecular bone and enlarged adrenals. Birds drinking the latter water had an elevated concentration of Na and calcium, and a decreased concentration of phosphorus and chloride in their serum, and elevated plasma protein levels. Ducklings reared on fresh or slightly saline water adapted very poorly to an abrupt change to more saline water (specific conductivity = 15,250 microns hos/cm) at 14 days of age. These birds stopped eating, became inactive and some died within 3 days; survivors had many tissue and biochemical abnormalities at 20 days of age. The level of salinity in these trials was similar to that in "brackish" or "moderately saline" wetlands and lower than that previously found to have effects on growth and feathering of ducklings. Many of the sublethal effects were subtle and non-specific manifestations of stress, and would be difficult to detect in wild ducklings on saline wetlands.     

Extra-pair copulation and paternity defense in the hihi (or stitchbird)

We monitored 16 radio-tagged moreporks (Ninox novaeseelandiae) on Mokoia Island after a brodifacoum poison drop to eradicate mice (Mus musculus), normally included in the owls' diet. All 16 moreporks were alive after 13 days. One bird was found dead on day 22, and corpses of two radio-tagged birds were located on day 51. The bird found on day 22 contained 0.97 mg kg(-1) of brodifacoum in its liver. The other two carcasses were not analysed, but they probably died as a result of brodifacoum poisoning. Thus, three out of 14 birds died (21% mortality). A further eight banded and six non-banded birds were also monitored. Of these, 50% were not seen following the drop. Secondary poisoning is implicated in the disappearance of these birds. Sublethal effects such as lowered breeding success and stress may have affected morepork over a prolonged period following the poisoning operation. Further studies are needed to investigate the exact pathway of this poison, especially the potential for invertebrates to carry poison.     

Paint chip poisoning of Laysan albatross at Midway Atoll

Epizootic mortality occurred in Laysan albatross (Diomedea immutabilis) fledgings at Midway Atoll in 1983. Heavy metal toxicity from ingestion of weathered paint chips was one of the causes. Sick albatrosses were unable to retract their wings, causing a "droop-wing" appearance. Five normal and 12 droop-winged fledglings were captured, killed, and examined. Paint chips found in the proventriculus of the affected fledglings contained up to 144,000 ppm lead. Blood, liver, and kidney concentrations of lead in affected birds were higher than in normal fledglings, and acid-fast intranuclear inclusion bodies were present in the kidneys. Degenerative lesions were present in the myelin of some brachial nerves. Weathered paint samples collected from 12 buildings contained up to 247,250 ppm lead and 101 ppm mercury. Lead poisoning was diagnosed in 10 of the droop-winged albatrosses and was one of the causes of morbidity. Mercury toxicosis and plastic impaction were other possible causes.     

Epizootic emergence of Usutu virus in wild and captive birds in Germany

This study aimed to identify the causative agent of mass mortality in wild and captive birds in southwest Germany and to gather insights into the phylogenetic relationship and spatial distribution of the pathogen. Since June 2011, 223 dead birds were collected and tested for the presence of viral pathogens. Usutu virus (USUV) RNA was detected by real-time RT-PCR in 86 birds representing 6 species. The virus was isolated in cell culture from the heart of 18 Blackbirds (Turdus merula). USUV-specific antigen was demonstrated by immunohistochemistry in brain, heart, liver, and lung of infected Blackbirds. The complete polyprotein coding sequence was obtained by deep sequencing of liver and spleen samples of a dead Blackbird from Mannheim (BH65/11-02-03). Phylogenetic analysis of the German USUV strain BH65/11-02-03 revealed a close relationship with strain Vienna that caused mass mortality among birds in Austria in 2001. Wild birds from lowland river valleys in southwest Germany were mainly affected by USUV, but also birds kept in aviaries. Our data suggest that after the initial detection of USUV in German mosquitoes in 2010, the virus spread in 2011 and caused epizootics among wild and captive birds in southwest Germany. The data also indicate an increased risk of USUV infections in humans in Germany.     

Epidermoptid mange in Laysan albatross fledglings in Hawaii

Mange caused by the epidermoptid mite Myialges nudus (Acari: Epidermoptidae) is described in 31 dead fledgling Laysan albatrosses (Phoebastria immutabilis) from Midway Atoll (Hawaii, USA) sampled from 18 June to 10 July 1990 and from 21 June to 22 July 1991. This is the first record for this parasite from this host. Mites were collected from the skin; were located primarily in the stratum corneum; and were associated with mild to severe granulomatous inflammation, hyperkeratosis, dermal edema, ballooning degeneration of keratinocytes, neovascularization, and subdermal fibrosis. The severity of inflammation in some birds suggested that dermatitis due to M. nudus could be a significant cause of morbidity, or even mortality, in these birds.     

A relationship between avian carcasses and living invertebrates in the epizootiology of avian botulism.

A survey of the sources of Clostridium botulinum type C toxin possibly utilized as food by aquatic birds in an epizootic area of avian botulism in northern Utah showed that living aquatic and terrestrial invertebrates normally found in close association with dead, decomposing birds commonly carried the toxin. Of 461 samples associated with 21 species of avian carcasses, 198 were toxin-positive. Invertebrate species not normally scavengers of vertebrate tissues were less commonly and less highly toxic, particularly when captured 30 cm or more from a carcass; six of 237 samples of such aquatic invertebrates low-level toxin. Of the species tested, blow fly larvae (Calliphoridae) were the most consistently and highly toxic, although others, particularly adult and larval stages of several species of beetles (Coleoptera), contained toxin at levels probably significant in the epizootiology of the disease. An estimated 0.05 to 0.25 g of the most toxic fly larvae or 15 g of the most toxic beetles tested carried a mediam lethal dose for an adult mallard duck. Examination of stomach contents of aquatic birds dead of botulism showed that some had consumed invertebrates.     

The death of birds on the sea coast of northeastern Sakhalin Island

The taxonomical composition of dead birds found on the northeastern coast of Sakhalin Island and the causes of their death were studied. Sites with high, average, and low concentration of dead birds were identified. The period of highest mortality of birds (July–August) coincided with the beginning of massive migrations of birds and large numbers of young birds after termination of the nesting season. Collection of bird remains in periods of bird migrations and breeding, in addition to other methods of ornithological research (visual observations, fowling, shooting), can provide useful information on the avifauna and ecological state of the investigated region.     

Pre- and postharvest effects of lufenuron on Epiphyas postvittana (Lepidoptera: Tortricidae)

First-, third-, and fifth-instar Epiphyas postvittana (Walker) were exposed to a range of lufenuron concentrations (0-200 ppm) incorporated into synthetic diet and their subsequent development and mortality responses were determined. For all instars the greatest change in mortality response occurred over lufenuron concentrations < or = 3 ppm. However, third and fifth instars displayed an increase in mortality earlier than first instars, and were more sensitive to the lower lufenuron concentrations in this range. Only first and third instars subjected to < or = 2.5 ppm lufenuron survived the 26-d exposure trial. No larvae first exposed to lufenuron as first or third instars survived to pupation if ingesting concentrations of > or = 1 and > or = 3 ppm, respectively. Consumption of lower lufenuron concentrations by these larvae delayed pupation and resulted in pupal deformity. In contrast, fifth instars subjected to 100 ppm were capable of surviving the 26-d trial period and displayed a slower progressive reduction in survival to pupation with increase in lufenuron concentration. Also in contrast to more immature stages, fifth instars exposed to lufenuron developed more rapidly to pupation than larvae not exposed to the insect growth regulator (IGR), and all resulting pupae were normal. Third instars were exposed to sublethal lufenuron concentrations (0-3 ppm) for 4 d and the fourth-instar survivors subjected to a controlled atmosphere cold storage treatment (2% O2, 2% CO2, 0.6 degree C). Larvae ingesting diet containing 0.5 ppm (and to a lesser extent 1 ppm) lufenuron required longer exposure to the postharvest treatment to achieve > or = 95% mortality than larvae not ingesting the IGR. However, the analogous mortality response of larvae exposed to 3 ppm lufenuron was comparable to the control.     

Highly pathogenic avian influenza in magpies (Pica pica sericea) in South Korea

Highly pathogenic avian influenza (HPAI) is an extremely infectious, systemic viral disease of birds that produces high mortality and morbidity. HPAI was diagnosed in the three dead magpies (Pica pica sericea) submitted to the National Veterinary Research and Quarantine Service. At necropsy, the prominent lesions were multifocal or coalescing necrosis of the pancreas with enlargement of the livers and spleens. Microscopically, there were severely necrotizing pancreatitis and lymphocytic meningoencephalitis. Influenza viral antigen was also detected in areas closely associated with histologic lesions. Avian influenza virus was isolated from cecal tonsils and feces of the magpies. The isolated virus was identified as a highly pathogenic H5N1, with hemagglutinin proteolytic cleavage site deduced amino acid sequence of QREKRKKR/GLFGAIAG. To determine the pathogenicity of the isolate, eight 6-wk-old specific-pathogen-free chickens were inoculated intravenously with the virus, and all birds died within 24 hr after inoculation. This is the first report of HPAI in magpies.     

The Disappearance Rate in Reindeer of Famphur an Organophosphorus Parasiticide

The present investigations were carried out in order to study the disappearance rate in reindeer of famphur (0,O-dimethyl-O,p-(NtN-di-methylsulphamoyl) phenyl phosphorothioate), a promising systemic parasiticide for the control of reindeer warble and nostril flies. The compound was administered intramuscularly to reindeer as a single dose (in the form of the preparation Warbcx). At a dose of 20 mg/kg body weight (2 animals) famphur caused inhibition of plasma and erythrocyte cholinesterase activities by about 50 %. The plasma esterase activity fell off rapidly, within 24 hrs., and returned to normal within 3 weeks, whereas the erythrocyte esterase activity decreased gradually and remained low for at least 4 weeks after dosing. Peak plasma levels of fampliiir, varying between 1 and 16 p.p.m., were attained within 5–33 hrs., after a dose of 30 mg famphur per kg body weight (7 reindeer). The plasma levels declined to below 0.02 p.p.m. in 72–96 hrs. Famoxon, the oxygen analogue of famphur, was observed for 1–2 days in plasma at low levels, amounting to about 10 % of the corresponding famphur levels. In erythrocytes practically no residues were found of either compound. Tissue residue levels were low — except at the injection site. In a series of animals given a dose of 30 mg/kg body weight and killed at varying times after treatment famphur or famoxon were detectable in liver for 4.5 days and in kidney and skeletal muscle remote from the injection site for 12 days. In muscle tissue from the injection site highly variable residue levels were observed, indicating absorption from the intramuscular depot to be erratic. The experimental results suggest that no appreciable consumer hazard would arise from a proposed single-dose intramuscular treatment of reindeer with famphur at a dosage not exceeding 30 mg/kg body weight, provided a minimum interval of 3 weeks is maintained between treatment and slaughter and the muscle tissue around the injection site is discarded.     

Forest bird mortality and baiting practices in New?Zealand aerial 1080 operations from 1986 to 2009

We collated 48 surveys of individually banded birds or birds fitted with radio transmitters that were checked before and after 1080 poison (sodium fluoroacetate) baits were aerially distributed to control brushtail possums (Trichosurus vulpecula) in New?Zealand forests. The surveys were associated with 34 pest control operations from 1986 to 2009 and covered 13 native bird species, of which four were kiwi (Apteryx spp.). Sample sizes ranged from 1 to 46 birds (median 15). In 12 cases a sample of 1 to 42 birds (median 13) was surveyed in an untreated area at the same time. In total, 748 birds were checked before and after operations and 48 birds disappeared or were found dead. In non-treatment areas, 193 birds were checked and four died. Surveys of kiwi, whio (Hymenolaimus malacorhynchos), kaka (Nestor meridionalis) and kokako (Callaeas cinerea) were grouped for meta-analyses. The 95% pooled upper confidence bounds for the point estimate of zero mortality were each less than 4% for kiwi, kaka and kokako indicating only a small risk of mortality during 1080 pest control operations. Prefeeding with non-toxic baits increased from 22% (1998?1999) to 79% (2007?2008) in 322 operations on public conservation lands but was used in only 9 (26%) of the operations during which individually marked birds were monitored. We caution that failure to observe bird deaths in small samples may lead to weak inference about zero mortality across a population, most surveys in the review did not involve prefeeding, and that 11 native bird species for which deaths were reported after 1080 operations have not been studied.     

Pilot study on the efficacy of paromomycin as a histomonostatic feed additive in turkey poults experimentally infected with Histomonas meleagridis

Paromomycin is an aminoglycoside antibiotic with activity against protozoa. Currently, paromomycin is registered for food producing animal species. In a pilot study we evaluated the efficacy of different doses of paromomycin in the feed against Histomonas meleagridis in experimentally challenged turkey poults. Groups consisting of 30 birds each were given feed with 100, 200 and 400 ppm paromomycin, respectively, starting on day 1 through to day 42. One group of 30 birds was left untreated. On day 21 all birds were infected intracloacally with H. meleagridis. Additionally, 10 birds were kept as a non-infected and non-treated control group. Before the challenge there was no significant difference between untreated and treated groups with regards to feed consumption and feed conversion rate. After the challenge, mortality was 80% in the infected non-treated birds. In the treated groups the mortality rate was 73.3%, 43.3% and 20%, respectively. No histomonal DNA was found in caeca and livers of the surviving birds. In addition, higher doses of paromomycin (200 and 400 ppm) led to reduced counts of Clostridium perfringens in the droppings. In conclusion, a prophylactic application of paromomycin as a feed additive was effective against the challenge with H. meleagridis under experimental conditions.     

Cyclopiazonic acid production by Aspergillus flavus and its effects on broiler chickens.

Cyclopiazonic acid (CPA) was purified from cultures of Aspergillus flavus, and ca. 14 g of the toxin was collected for use in feeding studies. Chicken rations were artificially contaminated with purified CPA at concentrations of 10, 50, and 100 ppm (microgram/g) and fed ad libitum to eight groups of chickens for 7 weeks. Chickens receiving feed with 100 ppm of CPA had high mortality, decreased weight gain, and poor feed conversion when compared with birds receiving other doses. Postmortem examination showed that chickens fed the two greatest doses of CPA had proventricular lesions characterized by mucosal erosion and hyperemia (100 ppm) and by thick mucosa and dilated proventricular lumens (50 ppm). Birds given 100 ppm of CPA in feed also had numerous yellow foci in their livers and spleens. Microscopic examination of tissues of birds that received 100 ppm of CPA revealed ulcerative proventriculitis, mucosal necrosis in the gizzard, and hepatic and splenic necrosis and inflammation. Birds given 50 ppm of CPA had hyperplasia of the proventricular mucosal epithelium. Birds given 10 ppm of CPA and control birds had no significant treatment-related lesions.     

Cyclopiazonic acid production by Aspergillus flavus and its effects on broiler chickens

Cyclopiazonic acid (CPA) was purified from cultures of Aspergillus flavus, and ca. 14 g of the toxin was collected for use in feeding studies. Chicken rations were artificially contaminated with purified CPA at concentrations of 10, 50, and 100 ppm (microgram/g) and fed ad libitum to eight groups of chickens for 7 weeks. Chickens receiving feed with 100 ppm of CPA had high mortality, decreased weight gain, and poor feed conversion when compared with birds receiving other doses. Postmortem examination showed that chickens fed the two greatest doses of CPA had proventricular lesions characterized by mucosal erosion and hyperemia (100 ppm) and by thick mucosa and dilated proventricular lumens (50 ppm). Birds given 100 ppm of CPA in feed also had numerous yellow foci in their livers and spleens. Microscopic examination of tissues of birds that received 100 ppm of CPA revealed ulcerative proventriculitis, mucosal necrosis in the gizzard, and hepatic and splenic necrosis and inflammation. Birds given 50 ppm of CPA had hyperplasia of the proventricular mucosal epithelium. Birds given 10 ppm of CPA and control birds had no significant treatment-related lesions.     

THE FOOD AND FEEDING HABITS OF SHELDUCK TADORNA TADORNA

The food and feeding habits of Shelduck Tadorna tadorna are described, based on the analyses of the viscera of 30 birds collected under special licence, and of 18 birds found dead or dying during the cold weather of 1963, on faecal material from eight incubating birds, on field observations and on the literature. The birds came from a number of different localities and from each month of the year, apart from July.
The mollusc Hydrobia ulvae (Pennant) was found in all 46 birds which contained food, and it is quite obvious, and this is confirmed by the literature and by faecal analyses, that this is the most important food item during much of the year and in many different localities. Other species eaten included the bivalve Macoma balthica , the amphipod Corophium volutator , the ragworm Nereis sp., the alga Enteromorpha , and occasionally the seeds of various plants.
The importance of H. ulvae is examined in the light of its distribution and numbers, which may be a strong controlling factor in concentrating Shelduck in certain areas at certain times of the year.
The feeding behaviour of Shelduck, and a number of other birds, is apparently closely related to the cyclic behaviour pattern of the main food species, H. ulvae .
It seems that Shelduck have a rather fixed type of feeding behaviour which exploits only one feeding niche and therein mainly one food item. Any event (prolonged gales or very cold weather) which prevents the bird from using that niche can be the cause of heavy mortality.     

Hailstorms as a cause of mass mortality of Swainson's hawks in their wintering grounds

We describe a mass mortality event of wintering Swainson's hawks (SH, Buteo swainsoni) in central Argentina during November 2003. One hundred thirteen SH were found dead as a consequence of a single hailstorm. In addition, 14 hawks with severe injuries were recovered alive, but only 10 of these survived 1 wk later. Another 45 dead birds of 11 species were collected in the area. Interviews with local land-owners conducted in other areas of the SH wintering grounds provided further evidence of past hailstorm-related mortality involving SH, suggesting that such events commonly occur in the Argentine Pampas. This potential cause of mass mortality of SH wintering in agricultural areas of Argentina may be significant when added to the increased mortality associated with poisoning events during the last decade.