Toxic birds

Similar to amphibians, the pitohui, a toxic bird in New Guinea, appears to derive its toxic alkaloids from its invertebrate diet (Dumbacher etal, 2000). 

Dumbacher, J. P., Spande, T. F., and Daly, J. W. (2000). Batrachotoxin alkaloids from passerine birds a second toxic bird genus Ifrita kowaldi) from New Guinea. Proceedings of the National Academy of Sciences of the USA 97,12970-12975. 

Bartram, S. and Boland, W., Chemistry and ecology of toxic birds, Chem. Biochem., 2, 809-811, 2001. 

Dumbacher JP, Spande T, and Daly JW (2000) Batracho-toxin alkaloids from passerine birds A second toxic bird... 

Physiological differences among species will markedly alter the susceptibility to toxicants. Birds are more sensitive to toxic vapors and gases than mammals. Canaries have been used in mines to test for the presence of poisonous gases because their elaborate respiratory system causes them to succumb to lower concentrations of toxic gases than would endanger humans. 

The effects of pollution can be direct, such as toxic emissions providing a fatal dose of toxicant to fish, animal life, and even human beings. The effects also can be indirect. Toxic materials which are nonbiodegradable, such as waste from the manufacture of insecticides and pesticides, if released to the environment, are absorbed by bacteria and enter the food chain. These compounds can remain in the environment for long periods of time, slowly being concentrated at each stage in the food chain until ultimately they prove fatal, generally to predators at the top of the food chain such as fish or birds. 

DDT is highly toxic to fish (LC q for trout and blue gill, 0.002—0.008 ppm), and it is only moderately toxic to birds (oral LD q mallard 1300 and pheasant >2240 mg/kg). However, widespread bird kills have resulted from bioconcentration of DDT through food chains, ie, from fish or earthworms. A significant environmental problem has resulted from the specific effects of DDE on eggshell formation in raptorial birds where accumulation has caused decreases in shell thickness of 10—15%, resulting in widespread breakage. 

Environmental. The A/-methylcarbamates generally are biodegradable and of low soil persistence with half-Hves for carbaryl and aldicarb of 1—2 weeks and of carbofuran of 1—4 months. Certain carbamates are highly toxic to birds with oral LD qS for mallard, eg, pheasant, in mg/kg carbofuran, 0.40, 4.2 mexacarbate, 3.0, 4.5 and methomyl, 16, 15 compared to carbaryl >2000. Fish toxicity of carbamates is generally low, but these compounds are extremely toxic to bees. In cases of human poisoning, atropine is a specific antidote. 

Avitrol [504-24-5] (4-anHnopyridine) (24), mp 155—158°C, bp 273°C, has repeUent—toxicant properties for birds and is classed as a severe poison and irritant. This secondary bird repeUent can be used as a broadcast bait, causing uncoordinated flight and distress caUs and escape responses in nearby birds (57). A reevaluation shows lack of effectiveness of 1% baits but better control of blackbirds with 3% baits (58). Suspected contamination of drinking water with 4-aminopyridine has been reported in toxicosis of Brahman catde and horses (59). 

The final article, by S. G. Bell and G. A. Codd of the University of Dundee Department of Biological Services, is concerned with detection, analysis, and risk assessment of cyanobacterial toxins. These can be responsible for animal, fish, and bird deaths and for ill-health in humans. The occurrence of toxic cyanobacterial blooms and scums on nutrient-rich waters is a world-wide phenomenon and cases are cited from Australia, the USA, and China, as well as throughout Europe. The causes, indentification and assessment of risk, and establishment of criteria for controlling risk are discussed. 

Terrestrial toxicity (to plants, earthworms, bees, birds)... 

Additional chronic toxicity Additional environmentally dangerous properties Toxicity to birds Long-term toxicity in water and soil Degradability simulation tests Additional abiotic degradability Mobility in water, soil and air cumulative... 

Contains information on the toxic effects of5,600 chemicals on more than 2,800 aquatic species of animals and plants, excluding birds, aquatic mammals, and bacteria. Has now been incorporated into ECOTOX Data System. Hours 8 00 a.m. to 4 30p.m. CST, Monday - Friday. 

Water birds have not been shown to be directly affected by acidification. However, the prey of waterbirds may be of concern as these lower food-chain organisms may have elevated levels of toxic metals related to acidification of their habitat. Moreover, most water birds rely on some component of the aquatic food-chain for their high protein diet. Invertebrates that normally supply caJcium to egg-laying birds or their growing chicks are among the first to disappear as lakes acidify. As these food sources are reduced or eliminated due to acidification, bird habitat is reduced and reproductive rate of the birds is affected. The Common Loon is able to raise fewer chicks, or none at all, on acidic lakes where fish populations are reduced 37 and 5S). However, in some isolated cases, food supplies can be increased when competitive species are eliminated (e.g.. Common Goldeneye ducks can better exploit insects as food when competition from fish is eliminated). The collective influences of acidification are difficult to quantify on a specific area basis but for species that rely on a healthy aquatic ecosystem to breed, acidification remains a continuing threat in thousands of lakes across eastern North America 14). 

Persistent metabolite of p,p - yUY implicated in the decline of certain predatory birds Mechanism by which binding to Ah receptor causes toxic effects still unclear... 

The organophosphorons insecticides dimethoate and diazinon are mnch more toxic to insects (e.g., housefly) than they are to the rat or other mammals. A major factor responsible for this is rapid detoxication of the active oxon forms of these insecticides by A-esterases of mammals. Insects in general appear to have no A-esterase activity or, at best, low A-esterase activity (some earlier stndies confnsed A-esterase activity with B-esterase activity) (Walker 1994b). Diazinon also shows marked selectivity between birds and mammals, which has been explained on the gronnds of rapid detoxication by A-esterase in mammals, an activity that is absent from the blood of most species of birds (see Section 23.23). The related OP insecticides pirimiphos methyl and pirimiphos ethyl show similar selectivity between birds and mammals. Pyrethroid insecticides are highly selective between insects and mammals, and this has been attributed to faster metabolic detoxication by mammals and greater sensitivity of target (Na+ channel) in insects. 

The two examples just given are of localized effects associated with the acute toxicity of DDT and DDD to organisms in higher trophic levels. A more wide-ranging toxic effect associated with population decline was eggshell thinning caused by the relatively high levels of p,p -DDE in some predatory birds (see Table 5.7). 

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