Tuesday, May 30, 2017

More on Great Spirit Bluff

We are getting a lot of questions about the perch design at Great Spirit Bluff. Are falcons jumping because the perches are poorly designed? No - they are jumping because of an unusually early and intense (what we call explosive) - emergence of adult black flies.

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.
A couple of comments on 2017 - the swarm was earlier than we have ever seen it and we have never at ANY of our cammed sites seen young falcons venturing outside at roughly 17 days of age. Not on platforms. Not on bars. Not ever, not anywhere.

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. 

18 comments:

Cindy Lam said...

There is a nice ledge right below the box. It has space to put the box and not that big drop. I have seen the babies go on this ledge before after they fledge.

Thank you!

Admin said...

This link is unreachable:
http://www.arcticraptors.ca/pdf_docs/Arctic69-3-281.pdf

prowild said...

Thank you for your comments.They are what we need to hear. We need to think about all the birds we don't see and are suffering out of sight and what we can do to help. Thank you. I was wondering about that open ledge below the box. Would that be appropriate for a falcon nest?
Thank you again for this opportunity.

Ronnie said...

Very interesting. I pray people will start listening to the scientists and believe global warming is real.

Nora H said...

Cindy Lam mentioned the ledge right below the box with space on it. The question I'd have is it accessible by any predators like raccoon or anything?

Jm said...

So what has happened to the surviving two after the banding? June 3 and mom is alone. She worked so hard to raise this brood.

elmale said...

It is clear by Lady Hawk's video that the falcons did NOT jump but fell! Build a better nest box or find a safer place to put it!

Deborah Ann said...

Thank you for the information. You are doing a wonderful job.

Okeyd57 said...

Here in southern West Virginia, we've been spraying the New River every Spring for black flies since the 1970,s. I don't see what that has to do with global warming.

Oh, that's right, it doesn't !

Daniel Cole said...

My opinion as a former falconer, those eyas may have been trying to escape the flies, but from the video I was watching they fell, they didn't jump. They need a platform they can walk on, outside the nest box, not those two boards. The ledge below is a better, and more natural spot for the nest box. Just my 2 cents.

elmale said...

Amen to that, Daniel Cole!

prowild said...

There is plenty of evidence of climate change for people who are open to educate themselves and willing to change in order to help. Whether controlling black flies is the answer or not, it will be the scientists who will have to weigh in. But this is only a place to enjoy the wonders of wildlife and see that life and death are a daily occurrence for animals and plants. Making it to adulthood is difficult and rare. Life is tough out there. We really appreciate the efforts of the Raptor Resource Project to show us this magnificent spectacle of how the falcons rear their babies.
Thank you

Jm said...

So are the last two chicks dead? Or have they been sighted?

Jm said...
This comment has been removed by the author.
Robyn McCracken said...

Thank you! Very hopeful!

Nora H said...

OK I'm not RRP, but have been around them a long time. I've also followed lots of other peregrine cams. As they said, at that young of an age they DON'T just venture out like that. There are nest boxes on cliffs, the edges of high roofs, ledges on buildings, it doesn't happen.

A nest box at a cliff site also has to be placed where raccoons and other predators can't get at the eggs and/or hatchlings.

With the black fly problem they very well could have gone off a platform trying to get away from the flies as well.

Ok, just my two cents.

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