Comments on: Lead Poisoning and Loons: A skeptical look

By: travc

travc — Mon, 03 Aug 2009 20:40:36 +0000

Good Ecology research is damn hard to do, as your pointing out. We only get to study very tiny snapshots of very complicated systems and are trying to deduce generalities.

Anyway, keep up the posts… they are quite interesting.

PS:
A word on lead shot. There are several very good reasons it is used. It is very heavy (2E=MV^2), it is melts at a relatively low temp (easy to work with), and it is soft (easy to work with and can deform to more efficiently convert kinetic energy into carnage).

However, all that said, killing a bird with a shotgun doesn’t take a lot of “umph”… and steel shot works perfectly fine and should be used by all hunters. There is more of a valid argument regarding bullets.

Lead fishing weights are just dumb. Get a pair of pliers and untempered steel (or just iron) works fine.

By: Michael Spencer

Michael Spencer — Mon, 03 Aug 2009 07:26:36 +0000

I love this qwacky site.

No, really.

By: Greg Laden

Greg Laden — Sun, 02 Aug 2009 20:50:47 +0000

PWDs? Yes, there are some. But they do not cause a damaging wake to the extent that water ski boats do. Also, the lake is too cold for PWD’s after the chicks are off the nest. The loon nest, is in an excellent location regarding wakes, and is probably OK, but it is a factor.

This is a large lake. The total use rate is lower than other similar size lakes, but there are plenty of boats. The lake is large enough (2,200 ha) to have aircraft land on it (they don’t land anywhere near the loons, though).

I will be addressing boats in a future edition of The Skeptical Loon….

By: doug l

doug l — Sun, 02 Aug 2009 20:40:18 +0000

I didn’t hear mention of the size of the lake or if there are wake-raising watercraft on it, but in lakes big enough so that loons can build up enough speed to get airborn, there are sometimes motorized craft. Loons, I understand, build their nests right at waterline in waters that are like what they are instinctually adapted to seek out. PWDs can really mess that up. I’ve heard this seriously mentioned by some field ornithologiests. Any of those little go-devils been toolin’ around your lake in the last few years? Just curious.

By: Greg Laden

Greg Laden — Sun, 02 Aug 2009 20:33:16 +0000

Bug Girl: Thanks for the comment. Yes, in one data set that I don’ think was Michigan but was in some loony state E of MN something like a fourth of the loons found dead (in 1995 IIRC) seem to have died of lead poisoning.

It probably does not take too many sinkers in the gizzard to kill a bird, considering that in the gizzard they are ground up and digested….

By: Greg Laden

Greg Laden — Sun, 02 Aug 2009 20:11:19 +0000

I should tell my Walden Pond story… which I probably did blog at some point … But for now, just for context: Walden pond does get like a million visitors a year. Most are not fishing, of course. In fact, it isn’t fished all that much. I’ve caught quite a few trout there, across the lake from the main beach. The point being, a lead sinker at Walden could be 150 years old! That pond must be loaded with lead! (Though I don’t think there is much waterfowl hunting there.)

By: justawriter

justawriter — Sun, 02 Aug 2009 19:21:31 +0000

Well dhogoza if you want to get into dueling ducks …
Canvasbacks – 16 percent above long term average
Redhead – 62 percent above long term average
Northern Shoveler – 92 percent above long term average
Gadwall – 73 percent above long term average
Green Winged Teal – 79 percent above long term average
Blue Winged Teal – 60 percent above long term average
Mallard – 10 percent above long term average
Total Ducks – 25 percent above long term average
Information is here.
Pintails are doing poorly, but they were only 20 below their long term average in 2008, instead of the 38 percent figure you quoted. Widgeons are also not doing as well as other ducks, but their population is only one percent below the long term average.
I also noticed that you linked to Audubon’s 2002 Watch List and that the Pintail was dropped from the 2007 Watch List. I would also point out that Audubon does not seem to have a “Birds Doing Well” list.

By: daedalus2u

daedalus2u — Sun, 02 Aug 2009 19:15:40 +0000

I know this is an anecdote, but some years ago I was at Walden Pond and went to pick up a pebble and it was a lead sinker with a significant corrosion thickness. It was about a quarter inch in diameter, and likely would be a fatal dose of lead if a bird had eaten it.

I only went to Walden Pond sporadically, but my cumulative time there was perhaps a few hundred hours. If I could find a lead sinker, a waterfowl likely could too.

The people with a substantial interest in wild birds are hunters, who also happen to be the ones who inject lead pellets into the environment via gunfire. There are lead free alternatives, there is no reason not to use them except cost. The cost of lead shot and lead sinkers is a tiny fraction of what hunters and fishermen spend on their activities. Switching to lead free alternatives isn’t that big a deal. At some point, lead will build up in the environment due to hunting. Better to reduce that buildup by stopping adding more now.

By: bug_girl

bug_girl — Sun, 02 Aug 2009 19:15:26 +0000

While I can’t speak to the reproductive success, I can tell you we still routinely run into lead sinkers when we do our waterfowl autopsies here in Michigan.

(In case you are curious, it’s mostly to let our interns look at the inside of a bird. If they are croaked already, no harm, no fowl. Har!)

By: CalderaGal

CalderaGal — Sun, 02 Aug 2009 18:42:44 +0000

Loons breed at age three. The loons you saw could be age 2 or 1. Lead poisoning will not necessarily cause them to not breed, but it could impact the offspring. I have seen crippled and dwarfed trumpeter swan cygnets that tests found to have high lead levels.