Monday, July 27, 2015

Bob Anderson

I am deeply sorry to confirm that Bob Anderson passed away this morning. Out of respect for Bob and his family, we are asking that everyone respect their privacy. Official announcements will be made here and on Ustream in the days to come. Our deepest condolences to Bob's family.

Although Bob was very proud of his work with the Decorah Eagles, his heart was truly in his peregrine falcon recovery work. This video tells the story of his cliff work and was a special favorite: https://youtu.be/USQs4Bwxa18

The photo shows him on Great Spirit Bluff. It was one of his very favorites - he loved to be on rope - and is how many of us will remember him. Fly on, friend and mentor. We will never forget you.


Tuesday, July 21, 2015

Decorah: the eagles, N2, and our plans

Camera and N2
As you might know, wind took down N2 in Decorah very early on Saturday, July 18. The limb that held the nest tree was sheared completely off, several trees in the immediate area were toppled, and a few rows of corn in the field near the nest were flattened. The eaglets and mom were quickly accounted for. Dad kept us wondering until Sunday morning, when he was spotted at a favorite perching place on top of the bluff near the hatchery. As sad as the loss of N2 is, it could have been so much worse. There was no loss of eagle or human life, the family wasn't using the nest, and Mom and Dad are in a period of latency. Once again, a traumatic event for us is simply a part of life for them.

So what's going to happen next? At this point, we are waiting to see what the eagles do. We expect that Mom and Dad will start building a new nest in the fall, most likely in October. We don't believe they will abandon their territory, although we don't know exactly where they will rebuild or whether they will go back to N1. We will be watching closely to see what happens. Will the question of alternate nests finally be answered, at least in this case? Will the eagles rebuild in the woods next to trout creek or choose another spot? When exactly will they start and what will it look like? Thanks to Jim Womeldorf's work in 2013, we have a great basis for comparison!

N2 from the back, splintered limb
Having said that, we can't guarantee a live stream from this location in 2016. Installing and cabling a camera is a huge project, especially if directional boring needs to be done. Once the eagles start working on a nest, we don't want to risk shifting them again. If we can find another solution - a ground cam, for example - we will, but it is hard to plan when we don't know what Mom and Dad will do.

Bob has been thinking about another Decorah eagle cam for quite some time. Eagles can nest anywhere, but a camera needs electricity and internet access - two things that are in short supply at many locations! Fortunately, he identified another possible location just this spring. We will be placing cameras there this fall while we wait to see what Mom and Dad do. If we can't put a camera in N3 this year, we will do it next year. If it is possible to put N3 online via a ground cam, as Jim Womeldorf did in 2013, we will. And if neither of the first two options are possible, we will continue to observe and report on Mom and Dad old-school style. 

A lot of people are asking how Mom, Dad, and the eaglets weathered the storm so successfully. Eagles and many other birds sense changes in barometric pressure hours in advance of incoming weather. While they can't forecast long-term changes in weather (a rough winter, for example), they do sense and respond to relatively immediate weather conditions. The eagle family and other area birds probably sensed the incoming storm and hunkered down in a safe, relatively sheltered area to ride it out. They have long talons with excellent gripping strength (400psi per talon!), and can change their aerodynamic characteristics by changing their shape. So the next time you know rough weather is in the forecast, watch the birds (and bees) and see how they react! 

A few links on the subject: 

Damaged corn




Friday, July 10, 2015

After The Fledge Weekend!

The eagles have fledged, but we haven't stopped having fun! Come to our After The Fledge party in Decorah, Iowa, from July 16 through July 19. Thanks to apex sponsor Ustream and the Decorah Chamber of Commerce for their support!

To register for the weekend, go here: https://goo.gl/MSmQ3T
For our forum thread on the event, go here: http://goo.gl/pUH3I1

Information

Thursday, July 16: Meet and greet at the opera house in Decorah's Hotel Winneshiek (map: https://goo.gl/SfJaFf).
  • 5pm to 8pm: Enjoy drinks and snacks while you meet moderators and other eagle lovers. We'll have some souvenirs for sale and fun surprises for everyone!
Friday, July 17: Kayaking, scavenger hunt, and volunteering with the Humane Society!
  • Kayaking, 1:00-3:30pm. Scott Iverson has planned a wonderful kayaking trip on the Upper Iowa in the Bluffton area about 15 miles north of Decorah. The scenery is spectacular and the paddling is great! For more information, follow this link.
  • 1-4pm: Volunteer at the Humane Society of Northeast Iowa. Details TBA.
  • Scavenger hunt, all day: The Decorah Chamber of Commerce has sponsored a scavenger hunt through downtown Decorah. Explore the area while racking up badges and competing for prizes! 
Saturday, July 18: Biking, talks, scavenger hunt, and dinner
  • Biking, 9:00am. Hit Decorah's lovely paved bicycle trail with Jim Womeldorf and several Ustream chat mods. We begin meeting at 9:00 and hope to leave at 10am. See you on the trail! 
  • Talks, 2PM: Valders Hall, Luther College. Printable map: http://www.luther.edu/campus/assets/campus_map_8.20.10.pdf.
    Google map: https://goo.gl/LKHavm
    Bob Anderson will introduce talks by Neil and Laura Rettig (Philippine Eagles) and Brett Mandernack (Bald Eagle tracking in the midwest). Neil and Laura will also bring their harpy eagle Cal. 
  • Dinner, 5:30pm. Hatchery. We are serving delicious Iowa pork, chicken, and corn. Don't eat meat? We also have a wonderful vegetarian option! 
  • Scavenger hunt, all day: The Decorah Chamber of Commerce has sponsored a scavenger hunt through downtown Decorah. Explore the area while racking up badges and competing for prizes! 
Sunday, July 19: Volunteer at the Humane Society of Northeast Iowa
  • 10am - 1pm, details TBA. 
Friday - Sunday
  • Tours of the fish hatchery (bring quarters to feed the fish!)
  • 6am'ish: Coffee and pastry at the hatchery
We hope to see you there! 


Monday, May 04, 2015

Can Bald Eagles Get Avian Influenza?

Can bald eagles get avian influenza? That question is increasingly being asked of us at Ustream and on Facebook. The short answer: We don't know. But let's take a quick look at the landscape so far.

What is avian influenza?
To quote the USDA: "Worldwide, there are many strains of avian influenza (AI) virus that can cause varying degrees of clinical illness in birds. AI viruses can infect chickens, turkeys, pheasants, quail, ducks, geese and guinea fowl, as well as a wide variety of other birds. Migratory waterfowl have proved to be a natural reservoir for the less infectious strains of the disease.

AI viruses can be classified as highly pathogenic (HPAI) or low pathogenic (LPAI) strains based on the severity of the illness they cause. HPAI is an extremely infectious and fatal form of the disease that, once established, can spread rapidly from flock to flock."

There are at least two different HPAI strains circulating right now: EA/AM-H5N2 and EA-H5N8. The USDA tells us that: "The H5N8 virus originated in Asia and spread rapidly along wild bird migratory pathways during 2014, including the Pacific flyway.  In the Pacific flyway, the H5N8 virus has mixed with North American avian influenza viruses, creating new mixed-origin viruses.  This is not unexpected.  These mixed-origin viruses contain the Asian-origin H5 part of the virus, which is highly pathogenic to poultry.  The N parts of these viruses came from North American low pathogenic avian influenza viruses." The same thing appears to have happened in the Mississippi flyway with H5N2. It is generally believed that waterfowl migrating north carried the virus into Minnesota, although it isn't known how it spread to confined poultry. They most likely contracted the virus while wintering in areas shared with infected Pacific flyway birds.

At present, the USDA reports that:

  • 114 avian flu detections have been reported.
  • 21,644,473 animals have been affected. The vast majority have been on commercial poultry farms that raise chickens, turkeys, mixed poultry, and pheasants.
  • The first detection was reported on 12/19/14 and the last detection was reported on 05/01/15.
While most of the detections have been reported in commercial poultry, wild birds can contract H5N2 as well. The vast majority of cases have been reported in waterfowl, including wigeon, canada geese, mallard ducks, wood ducks, northern shovelers, and teal. Unfortunately H5N2 has also been reported in birds of prey, including:
  • Coopers hawks
  • Red-tailed hawks
  • Gyrfalcons
H5N8 has been reported in:
  • Peregrine falcons
  • A bald eagle
  • A great horned owl
  • Gyrfalcons
On April 30th, Minnesota Public Radio reported that a Cooper's hawk in Yellow Medicine County was the first Minnesota wild bird to test positive for the avian influenza virus H5N2. However, a positive test from a dead raptor only means the bird was exposed to the virus, not that the virus killed it or that the bird spread the virus to other birds. In this case, it was killed when it flew into a window and the virus was found after the carcass was sent to The National Veterinary Service Laboratory in Ames, Iowa.

So what can we make of all this? Based on what we know now, the eagles in Decorah and Fort St. Vrain don't appear especially likely to succumb to H5N2 avian influenza.
  • While H5N2 can be spread through consuming infected prey, it has tended to spread in domestic animals after direct contact with fecal droppings or respiratory secretions of infected birds. This is less likely to happen in a highly dispersed bird like the bald eagle. The virus has only been reported in one bald eagle and a small handful of wild raptors.
  • No large die-offs of raptors have been reported in Minnesota, Iowa, or Wisconsin. All three states are conducting surveillance programs to identify to what extent the virus is present in wild birds.  
  • While waterfowl can carry the virus, it seems to primarily affect domestic large-scale operations. Backyard flocks of chickens have not been infected to nearly the same degree. The USDA has identified just 12 cases in backyard flocks, including five in Washington in January and February, plus others in Idaho, Kansas, Minnesota, Montana, Oregon and Wisconsin. Wild and backyard birds could have been exposed over time to low pathogenic versions of bird flu and developed stronger immunity as a result.
It is believed the virus will die as temperatures warm up and ultraviolet light increases.  In the meantime, I suggest the following links for more information, including influenza updates: 
How are states responding?
News Articles

Did you know?
In Minnesota, the DNR is working to identify the virus in wild birds. The agency is collecting waterfowl fecal samples throughout Minnesota; asking turkey hunters from Kandiyohi, Pope, Meeker, Swift and Stearns counties to submit their harvested wild turkeys for testing; and collecting dead birds of various species reported by the public. 

The DNR has collected 29 dead birds of varying species; nine have tested negative for the virus and 20 results are pending. Test results also are pending on the 37 samples from hunter-harvested wild turkeys. The agency has collected 2,749 waterfowl fecal samples – nearing its goal of 3,000 – and more than 2,200 have tested negative; results for the rest are pending. The waterfowl fecal sampling effort is designed to determine with 95 percent confidence whether the virus is present on the landscape in at least one percent of the waterfowl population. They really want to know if you find a dead turkey or raptor. Go to http://www.dnr.state.mn.us/avianinfluenza/index.html for more information.

The Raptor Resource Project has offered to collect samples while banding this year. I'm guessing the answer will hinge on whether or not we start seeing problems in the wild population. We will keep you informed if anything happens.

Thursday, April 30, 2015

Red-tailed hawk growth and development in the nest

Eaglets aren't the only thing growing right now! The two eyas red-tailed hawks at Eaglecrest are morphing into adults right before our eyes. Like bald eagles, different parts of their bodies grow at different times and different rates, reflecting developmental priorities and impacting behavior. How will hawks EC2 and EC3 (also known as Speckle and Snickers on the Eaglecrest Wildlife facebook page) grow?

  • 0-7 days: the culmen achieves maximum growth. Red-tailed hawks hatch with a culmen (the dorsal ridge of the upper mandible) that is about 30% of the maximum size it is likely to achieve in the nest. During a red-tailed hawk's first week of life, its already large culmen nearly doubles in length, going from an average of 6.9 mm in length to an average of 12.3 mm in length. Since the consumption of food is the root of all else besides, the hawk's food-consuming apparatus is given developmental priority. While the culmen continues to grow after week one, its rate of growth slows dramatically, becoming almost flat by week five. Bald eagles follow a similar pattern, although they have almost twice the growing time in the nest that red-tailed hawks do and their developmental milestones reflect that.  
  • 7-14 days: third toe and tarsus achieve maximum growth. Eating has priority, but movement isn't too far behind. A young hawk needs to move to build muscle and feed once it is past the point where Mom and Dad simply stuff food into its waiting mouth. In the second week of life, a red-tailed hawk's third toe and tarsus are given developmental priority. The third toe is the real stand out here, nearly doubling in length from 16.9 to 27.9 millimeters. With longer toes and thicker, longer tarsi, the hawks are better able to sit up, move around the nest on their feet and knees, and interact with one another. We see a similar pattern with bald eagles, who reach asymptotic mid-toe and tarsus size about half-way through their nestling period - 40 days, in their case. 
  • 14 to 21 days: body weight achieves maximum growth. With food intake well in hand, young hawks gain weight rapidly. While they've been growing all along, weight gain is the biggest actor in week three. The young hawks spend a great deal of time eating and sleeping as their weight increases. 
  • 21 to 24 days: weight gains decline, independence increases. During the fourth week, weight gain declines, the nestling hawks begin feeding independently, and feather growth takes over. The hawks have the strength and physical structures they need to stand upright on their feet, manipulate food, and feed on their own. At about day 24, the length of primary seven overtakes weight as the best indicator of age.  At this point, fledge is just two or three weeks away. 
  • 24 to 35 days: Feathers take front and center. As fledge comes closer, developmental energy is channeled into growing feathers. The primaries enter their maximum growth phase during weeks four and five, the two weeks prior to fledging. The young hawks will also be growing sub-adult feathers elsewhere, including their backs, their tails (which won't become red until molt two, in their second year of life), and their chests. 
  • 36 to 44 days: Time to fly! Feather growth will slow, but the growth of flight-related muscles is happening in leaps and bounds. Wingercizing will take front and center stage as they young hawks practice for the big event by flapping, wing-hopping, hovering, and eventually taking flight! 
Both red-tailed hawks and bald eagles allocate developmental energy into producing weight and structure first (day 0 to day 24), and feathers second (day 24 onward). While feathers often seem light and simple, these two distinct periods of growth point to the incredible amount of energy needed to produce a proper 'coat' of feathers. Enjoy the hawks now, since they will be leaving the nest soon. It takes just 44-46 days to grow a red-tailed hawk from hatchling to fledgling! 


Resources
Did you know?
Red-tailed hawks are excellent falconry birds. While their are many excellent falconry organizations, I'm most familiar with NAFA. Interested in falconry? Follow this link: http://n-a-f-a.com/

Wednesday, April 08, 2015

A Four Recap

Earlier this week, a follower asked us for a recap of eagle Four’s life. Four was one of three eaglets that hatched in 2014. While early life in the nest was fairly ordinary, gnats and record-breaking rain interfered with fledging. For the first time that we know of, only one of the 2014 Decorah alumni successfully transitioned to life in the wild. One of Four’s siblings was injured and went to SOAR, where he  remains. The other sibling died of electrocution from a high voltage transmission line not far from the hatchery.

Four’s transition from fledge to flight was a bumpy one. During her first month on the wing, Bob rescued her from a location at the side of a highway, a fence, some deep woods, and a corn field. She roosted on the ground, traveled only short distances, and remained in the vicinity of the nest longer than any other eaglet we are aware of. We were starting to ask ourselves if Four would ever go when, on October 19, she abruptly left. Between June 22, 2014 and March 1, 2015, we received 302 valid fixes on Four. She traveled a total of 686 miles, averaging 2.2 miles a day. She achieved her furthest distance from home on January 8, 2015, when she was tracked 159 miles south of her natal nest. Her longest contiguous flight took place on December 1st, when she traveled 34.8 miles between the Maquoketa River and a roost near Lake McBride. She was electrocuted on March 2nd, roughly 130 miles south of N2.

After Four was electrocuted, we documented her death and reported it to the US Fish and Wildlife Service. We also contacted Alliant Power with photos of the pole under which Bob found her. When we were told it was up to code, Bob decided to get a second opinion. Contact number two told us that several things needed to be fixed to make the pole safe for birds. We passed the information back to Alliant Energy and decided to survey the area for more eagles. Two Ustream mods volunteered to conduct the survey for us. They didn’t find any eagles, but they did learn about another electrocution. They provided photos of that pole and several others. Alliant stated that they would fix the fatal poles and others like them. Thank you very much to IzzySam and Faith for taking this on for us.

We plan to take a trip back into the area where Four died to see whether Alliant fixed the poles as promised. The code we used to follow the travels of our eagles will be repurposed to map electrocutions and identify problem spots. While not every pole can be immediately protected, we can make dangerous poles a priority. Four touched a lot of hearts during her brief life. It is our hope that her death will bring about a safer environment for eagles and other birds.

Four's data is retained here: www.raptorresource.org/maps/latest.php.

What can you do?

  • Find out whether your utility has an avian protection plan. If they don't, they should consider adopting one. An APP helps keep animals, equipment, and people safe. http://www.aplic.org/APPs.php
  • Report electrocuted birds and other animals to your power company. Electrocutions are deadly to animals, harmful to equipment, and potentially dangerous to human beings. 
  • Report collisions to your power company. While our eagles have been electrocuted perching on poles, collisions are also deadly. Swan diverters and other deterrents can be installed.
  • If you are a member of an electric cooperative, make your concerns known to the board. I know of at least one electric cooperative in the process of retrofitting all their poles are safe. Electrocutions destroy equipment, require unscheduled repair time, and are expensive. 

Tuesday, March 24, 2015

Egg Colors and Shapes

The Chicago Peregrine Program inspired me to write a quick blog on the colors and shapes of eggs. Bald eagles have white eggs, peregrine falcons have eggs that range from light cream through brick red, and red-tailed hawks have pale eggs that are lightly splotched with brown. How and why do the birds we watch lay differently-colored eggs?


In general, female birds inherit egg colors and patterns from their female parents, who are ZW heterogametes. Egg-shell is made primarily of calcium carbonate, a white material, so the default color of all eggs could be considered white. As an egg moves down a female bird's oviduct, it squeezes or presses against glands that produce colored pigments from the breakdown of hemoglobin. Some colors (blues and greens) are applied very early on in the shell forming process, while others (brown) are applied quite late. Color may be applied relatively evenly or in drips and drabs depending on the bird and the speed of the egg through the female's oviduct. If the egg is stationary or moving very slowly, it may be solid, blotched, or spotted. If it is in motion, it will be streaked.

Coloring eggs carries a metabolic cost, so why aren't all bird eggs white? It's believed that birds with white or nearly white eggs have nesting strategies that hide their eggs from predators without the use of color. They might nest in cavities like barn owls, cover their eggs in vegetation like geese, or begin incubation immediately, like bald eagles. Since the eggs aren't visible to predators, camouflage colors and/or cryptic markings don't provide a survival advantage. Birds that lay colored eggs tend to nest in places or ways that are more visible to predators. Peregrine falcons, for example, don't usually begin full incubation until after their third egg is laid. The red color and light speckling helps conceal peregrine eggs when Mom and Dad aren't sitting on them and could make the eggs harder for nest invaders like raccoon to find. Ten or 20 seconds might buy enough time for enraged parents to drive nest intruders away.

So why do red-tailed hawks lay lightly speckled eggs while eagles lay white, highly visible eggs? Both birds begin full incubation right away and nest in fairly similar ways. We don't know for sure, although eagles in general are highly visible (giant nests, flashy black and white colors, six-foot wing spans) while hawks tend to be more concerned with concealment. The differences in egg-coloration might reflect some aspect of their lives we don't understand, but either way, egg-coloration is driven by survival. Hawks must need to conceal their eggs where eagles do not.

Predators aren't the only problem birds face. Some birds commonly lay or dump eggs in the nests of other birds. Splotched, spotted, or streaked eggs may help individual birds recognize their own particular markings and reject eggs that don’t match. So why don't Canada geese, which egg-dump, lay patterned or marked eggs? In general, I suspect that dumped eggs don't impact the survivability of original eggs very much in Canada geese. They are precoccial, so young require less parental investment once the eggs hatch. Canada geese also time hatching quite tightly, so an egg dumped at the wrong time won't survive.

How about egg shape? Peregrine falcons, Bald eagles, and Red-tailed hawks lay differently colored eggs, but the eggs of all three species are elliptical or oval in shape. Elliptical eggs nestle nicely in a scrape or nest cup where they sit side by side or in a line. However, the eggs of cavity-nesting birds like the Barn owls at Eaglecrest may be almost spherical. These eggs tend to cluster at the bottom of the tree hole. Their shape makes stacking a little easier, which helps the female incubate all of them. We tend to think of eggs as neat ovals, but some birds, like the killdeer at Eaglecrest, lay pyriform eggs. These oddly-shaped eggs are tapered, which causes them to roll in a tight circle. In the case of ledge-nesting birds, pyriform eggs are less likely to roll off, while killdeer eggs tend to stay in the nest scrape instead of rolling across gravel or stones where they could break.

In general, egg color and shape is influenced by survival. Female birds that produce more young will out-compete female birds that don't. Egg-color and shape may be influenced by overall health (healthier birds tend to lay more vibrant eggs), metabolic cost, the need to hide from predators, the need to identify one's own eggs, and the incubation advantage shape confers in any given circumstance. In all cases, our parents have demonstrated egg-ceptional egg-care. We look forward to hatching soon!

Things that helped me learn and write about this topic: