Lead Poisoning in Birds?

Question

I was watching something on the news last night about a town here in Australia with lead contamination issues. Apparently they are finding large numbers of birds-honey eaters, and nectar eating parrots dead from the lead. They have also found high lead levels in rainwater tanks. What I am wondering is why these particular birds are the ones affected? Other birds in the same area would be drinking the water, eating the grass etc.... Any ideas?

Thanks to those who have answered so far. I'm not interested in the cause of the contamination. I am looking for ideas as to why these particular bird species seem to be the most profoundly affected. There would be a large number of other species of birds living in the same area as the birds who have died. Why are these particular species bearing the brunt of the contamination?

Answer 1

Different species of bird are affected by lead in different ways. The more sensitive ones to it are likely the ones dying off. That's not to say that the other birds aren't suffering from it but the effects may be low reproductive rates, or simply slower die offs that aren't noticed as much. Just as an example when they were first releasing the California condors back into the wild the birds were ingesting massive quantities of lead (unfortunately still are and some die because of it), luckily the birds also happen to be quite resistant to it's toxic effects but still had to be treated because the levels are still dangerous if they go past a certain level, this is probably one of the reasons why breeding has been so difficult in the wild since so much lead is passed on into the eggs and the young are fed contaminated food etc. Sensitivity of some species may be the issue but other birds may be prone to simply ingesting more lead, I'm not to familiar with Australian parrots but if there's lead shot they may be attracted to something that is "shinny" and eating it this getting lots of lead very fast. For the honey-eaters one theory that could add more lead to their diet is if the plants they prefer are effective at bio-accumulating lead, imagine a nice lunch of lead flavoured nectar/pollen.

Answer 2

There are at least three possible reasons;

1) The lead contamination might be more concentrated in some areas than others.

2) Lead might be more concentrated in some food sources. For example, both of the birds species mentioned feed on plant nectar; the plants may be concentrating lead in the nectar at higher levels than found in the local water.

3) Similarly to the above, lead in plain metallic or even unbound ionic form (e.g. dissolved in water) is less readily absorbed - and thus less toxic - than lead which is bound to organic compounds which may be actively absorbed by the body.

Examination of the bodies and an epidemiological study of the affected birds may provide better information.

Answer 3

A cursery idea: These are more visilbe/noticable. Could be more shallow reporting as your question is good.
Causes: maybe lead soldering of tanks (but this would have turned up sooner, unless there is a "new kid on the block" with a diffrnt. method.) Some kind of spray?
Or perhaps the lead in the air is building to intollerable levels.

Answer 4

Pellett guns? Its an old past time, going into your back yard and popping a couple birds with .177 calibur lead pellett fire.

Total guess

Whatever species of bird lives near whomever is doing the shooting