The count of toasted birds at the Ivanpah Solar Electric Generating System doubled in April. Two possibilities for the accelerating death count.
First, the wing-toasting solar tower was in operation a higher number of hours in the month. Second, staff from the U.S. Geological Survey were on site a lot during the month giving a more accurate count.
Check out April Was Bad Month for Birds at Ivanpah Solar, by Chris Clarke at ReWire.
Mr. Clarke says the Ivanpah monthly compliance report lists 100 birds as either killed, mortally wounded, or injured during April. That consists of 40 that were scorched, singed, or had melted feathers and 12 showing signs of collision with heliostats. That is 52, so that leaves 48 decomposed enough that the cause of death couldn’t be determined. By biologists. Who know what they are looking for.
Actual deaths are a large multiple of the reported number
My reading of the March report and various other articles indicate to me that reported counts are actually a subset of the actual deaths – what is reported is an absolute bare minimum of the actual mortality.
Why?
First, the counts are performed infrequently leaving scavengers opportunity to eat or carry away many birds. Any birds carried back to the den to feed the baby coyotes or baby foxes aren’t included in the official count..
Second, the counts don’t include birds mortally wounded but still strong enough to fly a few more miles or barely strong enough to glide just outside the perimeter of the facility.
A new third reason is the counts don’t cover the full facility.
Check out this comment from the article:
But those searches still covered just 20 percent of the facility, meaning that one could reasonably extrapolate that total bird mortalities for April could be five times the official count. And that’s not taking into account injured birds that land outside the fence, or are eaten by scavengers before survey crews can find them.
The surveys cover one-fifth of the area inside the perimeter. One-fifth! In auditing we would call that a sample. Add to that the infrequency of the counts. Again, that is a sample.
Samples are merely a subset of the full population. You must extrapolate the sample in order to estimate the population. The reported mortality ought to be extrapolated to estimate the actual mortality.
Therefore the actual number of toasted wings is far higher than what is listed in the compliance report.
Waterfowl
Mr. Clarke indicates there were some waterfowl on the list in April. Two issues raised by that comment.
First, that means migratory waterfowl are probably landing and dying on sand and heliostats when they think they are landing on water. Mr. Clarke has labeled this the “fake lake effect.”
Second, I think almost all waterfowl are protected under the federal migratory bird act. That makes ‘taking’ them without a permit illegal.
Does Ivanpah have a heron hunting license? Can you get those by mail from the USPS like you can buy duck stamps for hunting mallards? Are herons in season during April? I don’t know the answer to these questions because I’m not a hunter. Can a hunter out there enlighten me?
Two month mortality count
Here’s the count from March and April along with data from last September and October:
- Sep -Oct -Mar -Apr -cause of death
- 15 – 22 – 22 – 40 – toasted
- ? – ? – 2 – 12 – collided
- ? – ? – 31 – 48 – unknown (so decomposed that experts can’t tell)
- 34 – 53 – 55 – 100 – total
There is a distinct possibility the number of dead birds didn’t change during April. It might just be that the increased attention on mortality merely found more birds that otherwise would have been missed in any previous month. Maybe the count in March would have been 100 if USGS had been on site.