Why are we so sure? The sites at which we have platforms (Xcel Energy's Allen S. King and Sherco plants, for example) don't have better production records than the sites at which we don't (every cliff site, sill-mounted sites at power plants, and stackhouse sites, to name a few). Great Spirit Bluff didn't begin having problems until our first black fly hatch in 2013. As you can see below, the only exception was 2008, and I suspect we had a new female (probably Michelle's first year) because the nest chronology really went very late, shifted early the next year, and stayed early. We installed the nest box here in 2003, falcons adopted it in 2005, and we put it online in 2011. Here is what the record looks like. You can check it for yourself at http://www.raptorresource.org/about-us/annual-reports-and-papers/
- 2005 - 4 falcons produced
- 2006 - 3 falcons produced
- 2007 - 3 falcons produced
- 2008 - 1 falcon produced
- 2009 - 4 falcons produced
- 2010 - 4 falcons produced
- 2011 - 4 falcons produced
- 2012 - 3 falcons produced
- In 2013, we banded four young. All of them stampeded from the nest following a blackfly swarm. We recovered one from the ground below the cliff and transplanted him to a nestbox with two young of the same age. He survived and fledged just fine. Two other falcons must have survived and been fed by the parents, because they showed up at the nestbox one day, all feathered out and looking great. One probably died - we never saw it again and it hasn't turned up anywhere else yet.
- In 2014, only one egg hatched. Watchers might remember that as a really brutal spring. We banded the lone male, but he stampeded from the nest box at about 30 days of age following a black fly swarm. We found him below the bluff with our cameras and monitored him as his parents cared for him. He fledged just fine.
- 2015 - 4 falcons produced
- 2016 - 4 falcons produced
- In 2017, two young falcons died following a black fly swarm. We recovered both carcasses, did a field examination on one (referencing 'Managing Peregrine falcon at the Eyrie' by Cade), and took the other into the U of MN for an autopsy. We are still waiting for the results from U MN. The one we examined had multiple bites along the edges of both wings, its wingpits, the skin around its eyes, and its cere, It had a couple of bites (but not many) in its thighpits. There were no bites or sign of insects in its mouth, its nares, or its nasal passages. I did a field examination on the two survivors when we banded Sunday, and neither one of them were nearly as badly.
We are researching ways to design a box that will minimize black fly swarming and offer a slightly larger platform, but if this is a problem with the falcons we watch, it is also a problem for countless birds we can't see. It is time to start thinking about ways that climate change is impacting the birds we watch and love and the birds we love but can't see. If we don't recognize the problem or confine the problem only to what we can see, we can't make a difference.
So why do we think the falcons died? We are still waiting for autopsy results, but black flies are a vector for blood parasites that kill young birds with undeveloped immune systems. A link: http://www.arcticraptors.ca/pdf_docs/Arctic69-3-281.pdf. Whether or not you understand that climate change is linked to anthropomorphic activity, use your favorite search tool to learn about climate change, black flies, and mosquitoes, just to name a few.