Laura Erickson's For the Birds

Thursday, March 28, 2013

Bridget Stutchbury's book, "The Private Lives of Birds"

I’ve been reading a fascinating book by Bridget Stutchbury, The Private Lives of Birds: A Scientist Reveals the Intricacies of Avian Social Life. The book came out in 2010, but I didn’t read it until recently. Bridget Stutchbury is a well-known researcher at York University in Toronto. She specializes in the behavioral ecology of migratory songbirds, and achieved international fame when she placed geolocators—tiny tracking devices—on Purple Martins and Wood Thrushes during one breeding season and retrapped the birds the following spring.

Geolocators are very tiny—one device and the harness used to hold it just above a bird’s rump weigh less than one gram. All a geolocator does is to record light levels and the time of day, and scientists must retrap a bird and remove the geolocator to retrieve any data, so the technology is useful only for species with high site fidelity, likely to be caught again the following year. Day-length varies with latitude and the time of solar noon varies with longitude. Data from a geolocator can reveal a bird’s entire migratory path and where it spent the winter accurately to about 125 miles for latitude. They provide much better resolution for longitude. Satellite tracking devices, used on loons, osprey, and other large birds, are significantly more precise but much too heavy for songbirds. Scientists don’t put any device weighing more than 4 percent of a bird’s body weight on it. Geolocators are tiny enough to weigh more like 2 percent of the weight of medium-sized songbirds such as thrushes and martins, and for now provide the best information we have for working out migration and wintering locations for Neotropical songbirds.

  This information is extremely useful not just for learning cool stuff about various birds, but also because in many species, local breeding populations may winter in different locations from other breeding populations of the same species. Some birds of conservation importance have robust populations in one state but may be declining dangerously in another. The problems causing a decline may be due to factors on the breeding grounds, but may also arise along the migration route or on the wintering grounds. Without knowing the migration pathways and wintering areas for different populations, we have no way of figuring out what is going wrong in one case but not the other, and have no chance to try to correct it.

 Bridget Stutchbury’s seminal research led to her 2007 book, The Silence of the Songbirds, subtitled "How we are losing the world’s songbirds and what we can do to save them," a wonderful book I devoured as soon as it came out. She also is co-author of a fantastic textbook, Behavioral Ecology of Tropical Birds, published in 2001. So her Private Lives of Birds is based on a vast body of research put together by her and her students through her career, using state-of-the-art technology and good old fashioned field work.

It’s a fun read, because she elegantly explains how she and other researchers figure out each piece of information even as she’s keeping her focus on exactly what the title says, the private lives of birds. For example, scientists banding nesting birds have long known that most songbirds are monogamous. So they were mystified when DNA analysis in more and more species established that a single brood of nestlings raised by supposedly monogamous birds all were likely to have the same mother but one or more of the chicks may have been fathered by one or more males other than the one raising them. Stutchbury explains the advantages to birds of this “extra-pair paternity,” and explains what male birds do to try to keep their own mates faithful even as they try to mate with other females.

Her writing is fun and accessible as well as authoritative. Here and there she or her editors made minor errors: one does not see large numbers of crocodiles on a Texas island. And sometimes I squirmed thinking about the individual birds that were experimented upon for her to make many of her discoveries. It sounds like she didn't "sacrifice" any birds, but trapping one of a mated pair and keeping it off territory for hours or days to see whether it could get the territory back was probably pretty unpleasant for both that bird and the one trying to take over the territory. Fortunately, she has a track record of using the valuable information from these experiments to promote bird conservation that ultimately can benefit those individual birds as well as larger populations.

The book is chock full of valuable facts and insights, and is well worth reading for anyone who wants to understand more about the private lives of birds.

Tuesday, March 26, 2013

Mark Dayton, Then and Now

Common Loon
Loon and human adults and babies require clean water and air. 

In the fall of 1982, during Minnesota’s Congress and Senate races, I wrote to each candidate asking what his stand was on several issues that would affect my new baby’s future. The one of highest importance to me then and now was the environment. All but one of the politicians responded with a form letter. The exception was Mark Dayton, who sent me not just one but two letters.

1982 Letter from Mark Dayton
My scanner isn't working, so these are photographs of Dayton's letters.

1982 Letter from Mark Dayton

1982 Letter from Mark Dayton

Both letters addressed each of my concerns, and Dayton’s positions were stated forthrightly.

 He wrote, “Like you, I am very concerned about the quality of our country’s natural environment. Clean air and water are the foundation for the Minnesota way of life. We must make sure to protect it.” In one letter, he expressed concern about “cuts in the Environmental Protection Agency’s budget,” noting “We need senators and congressmen representing this state who will commit themselves to strong enforcement efforts by the EPA."

In the other letter, he wrote, “I support immediate reauthorization of the clean air and water acts. The Environmental Protection Agency’s budget must be increased.”

How things have changed! Two weeks ago, when speaking to the Minnesota Chamber of Commerce regarding PolyMet Mining Corporation’s proposed copper-nickel mining project in northeastern Minnesota, Mark Dayton said he wished he could abolish the EPA. And when speaking at a town hall meeting in Duluth on March 20, he affirmed his statement, griping that the permit process was too slow.

Dayton now wants to streamline the process so permits can be issued within 150 days of a proposal. This would be fine for simple projects not likely to have serious environmental impacts, but the permitting process is designed so objective reviewers can evaluate complex projects and deny permits or require modifications when a proposed project’s potential dangers are greater than its potential advantages.

Heavy metal mining is fraught with environmental dangers—some projects have devastated major waterways and groundwater supplies, leading to major bird die-offs and soil and water too toxic for human use. The permitting process isn’t supposed to be like getting a new drivers license or passport—the EPA isn’t supposed to rubber stamp each and every proposal on a simple timeline. PolyMet’s original environmental impact statement was rejected because it contained insufficient data to establish that impacts from the proposed mine would be less harmful than impacts from similar mines have been. Should this project be approved before PolyMet submits an acceptable environmental impact statement and the EPA has time to review it?

PolyMet, with corporate headquarters in Canada and wealthy shareholders around the world, plans to extract Minnesota’s valuable minerals for profit, without paying the state or its people any royalties. That is an exceptional privilege, which should come with reasonable responsibilities to ensure that we the people of Minnesota are not losing more than just our state’s geologic treasure.

Our people up here certainly need jobs, and any of us who use electricity depend on copper mining. But those of us who live right here have a right to ensure that any mining is done in an environmentally responsible way.

Dayton said it was wrong to “expect some group of people who work down in Chicago to have any real motivation to make the changes necessary to allow us to move forward and create jobs here in Minnesota.” But the scientists and regulators working at the EPA offices in Chicago are far more likely to be both knowledgeable and objective about potential environmental hazards of a mining project than politicians and state agencies that are being strong-armed by multi-national corporations with an agenda. The EPA process is only supposed to approve any project after being given all the information they need to be sure it will not irreparably harm our air and water.

Right now we’re watching the climate change before our very eyes. Monarch butterfly numbers are in a tailspin because of lax enforcement of pesticide laws here and habitat destruction in Mexico. Do we need to kill our rivers and lakes before people will once again understand that the EPA exists to protect us, the people and wildlife of America, not to rubberstamp every project that comes down the pike?

Monday, March 11, 2013

Book Review: The Unfeathered Bird by Katrina van Grouw

The saying, “There’s nothing new under the sun” is as applicable in the world of bird books as anywhere else. Innovations are always been preceded by something that inspired them. The Golden field guide, published in 1966, was the first to include sonagrams—spectrographs of bird songs. Yet in 1904, F. Schuyler Mathews’s Fieldbook of Wild Birds and Their Music included musical notations that were an early attempt to show pretty much the same thing—sound frequencies vs. time. 

Roger Tory Peterson has always been credited for what is called the “Peterson system” of using patternistic drawings with little lines or arrows pointing to important field marks, which Peterson first used in his 1934 field guide. 

But Ernest Thompson Seton’s book, Two Little Savages, published in 1917, included drawings almost identical to some of Peterson’s, and Seton used letters the way Peterson used arrows to point out important features. 

Peterson did credit Seton’s inspiration in his foreword, but readers virtually always give credit not to the person who first came up with an innovation but with the first person to make it famous. As with everything, the best bird books are built on the firm foundation of earlier works. Isaac Newton famously said, “If I have seen further it is by standing on the shoulders of giants,” but even this wasn’t a new thought. A good 500 years earlier, in 1159, John of Salisbury wrote of an even earlier person, “Bernard of Chartres used to say that we are like dwarfs on the shoulders of giants, so that we can see more than they, and things at a greater distance, not by virtue of any sharpness of sight on our part, or any physical distinction, but because we are carried high and raised up by their giant size.” There is nothing new under the sun.

When my kids were little, Russ and I got a series of wonderful magazine-style publications called Zoo Books. My favorite feature of the bird Zoo Books was a brightly colored, accurate drawing showing what that species looked like under its feathers, under its skin, and under its muscles. I have always been fascinated by the “inside story” of how bird bodies work. The Zoo Books drawings were based on specimens and scientific drawings, bringing what could have read in prose as dry anatomy to vivid life.

So I was delighted when Princeton University Press sent me a copy of Katrina van Grouw’s new book, The Unfeathered Bird. As I said, the concept of depicting birds beneath their feathers is hardly new, but van Grouw’s execution is not just fresh—it’s hauntingly, astonishingly beautiful as well as an incalculably valuable contribution to science, education, and art. 

Far more comprehensively, in breadth and in depth, than Zoo Books, she has produced 585 drawings of 200 bird species. Van Grouw may be uniquely qualified to produce such a work. She’s former curator of the ornithological collections at London’s Natural History Museum and a taxidermist, giving her a first hand knowledge of the insides of bird bodies. As a bird bander, she has held in her hands living, breathing birds as well, watching and even feeling their bodies unfold into flight as she released them from her own hands. And she’s trained as a fine artist as well. 

Her illustrations of musculature and details of eyes, orbits, bills, ears, feet, skulls, wings, tongues, and bones are exquisitely rendered, but hardly dry anatomical renderings. In her hands, these specimens come to life, sometimes depicted with wickedly lovely humor. Her Red-and-green Macaw stares straight at the reader, stripped of its feathers and skin to show its musculature as it bites a pencil held to its beak with a beautifully detailed foot. Her Budgie is a skeleton perched on a birdcage dowel, its empty eye sockets staring into a mirror.

She poses most of her birds in vivid action—her depiction of a Northern Gannet is an articulated skeleton in arrow-like diving posture. Her European Nightjar holds its capacious mouth wide open. When I was rehabbing, I specialized on a close relative, the Common Nighthawk, and for a time worked on a Ph.D. research project on nighthawk bodies. I was going to be Gary Duke’s first avian physiology Ph.D. candidate to complete my research without sacrificing a single bird, but I did dissect already-dead nighthawks, and even prepared a few articulated skeletons. The first time I did this, I was astonished at how scrawny a nighthawk’s body was beneath the feathers. Most of us readers will be astonished by a great many of the avian features revealed in this wonderful book. And the elegant prose puts each body in full evolutionary context. She writes, “The bugling call of a flock of cranes is among the most evocative sounds in all nature and is audible at a great distance. The comparison with the stirring fanfare of a bugle is no accident. The far-reaching cries of cranes are produced with a wind instrument of their own—an elongated windpipe or trachea—which coils in the same way as man-made musical instruments.” Her lovingly rendered Whooping Crane drawing shows the trachea coiled within the breastbone like a beautiful brass instrument.

It’s only March, but I’ll be shocked as well as delighted if another book comes out that competes with The Unfeathered Bird as the top bird book of 2013. Interestingly, Katrina van Grauw also illustrated my favorite bird of 2012—the extraordinary Bird Sense: What It’s Like to Be a Bird, by Tim Birkhead. Bestselling bird books tend to be field guides to identification, but I am far more enamored with books that give real insights to how birds live and perceive their worlds. The Unfeathered Bird perfectly fits the bill.

Here's an interesting interview with Katrina van Grouw for the Smithsonian.

Friday, March 8, 2013

Setting Free the Evening Grosbeak

Evening Grosbeak
Adult male Evening Grosbeak (photo from August 2011)
On January 14, someone brought an adult male Evening Grosbeak to the Wildwoods Rehabilitation Center in Duluth. His beak was injured, soft tissue in his right wing was damaged, and his crop was torn so that when he ate, the seeds came out through the hole. Apparently the poor bird had tangled with an attacker, though probably not a cat. Evening Grosbeaks are one of the most vulnerable species to window strikes, and it’s possible this one hit a window and while it was dazed, a squirrel, jay, or other opportunistic animal got it, or it’s possible that it escaped after a hawk or shrike attack.

The people at Wildwoods cleaned out the grosbeak’s wounds, gave him antibiotics and subcutaneous fluids, immobilized his injured wing, and found him a ride down to the Wildlife Rehabilitation Center of Minnesota, in Roseville. There he underwent surgery to fix his crop. He wasn’t easy to deal with. Evening Grosbeaks have powerful beaks and are quick to use them in self-defense. Whenever he needed to be handled to treat any of his injuries or rewrap bandages, he’d bite, which would reinjure his beak again.

He was healed and ready to go by last weekend, so they sent him back north for release. By then, the person who brought him in was no longer getting grosbeaks at her feeder. Evening Grosbeaks are extremely sociable birds, seldom seen as individuals, so Wildwoods knew it would be better for the bird if they released it where other grosbeaks were rather than back where he came from. They put out the call on Facebook looking for anyone who had a feeder where grosbeaks were visiting. Unfortunately, even in the few places they were appearing through the winter, they’ve pretty much disappeared. Fortunately, there were still a handful hanging out at a popular feeding station in the Sax-Zim Bog, so on Wednesday, I drove out there with the bird to release him.

Grosbeaks aren’t reliable even in the bog anymore. I waited for almost an hour without hearing a single one. I wanted to release the bird early enough in the day that he’d have plenty of time to adjust to freedom again, especially because Evening Grosbeaks tend to start roosting in mid- or even early afternoon, so finally I played some Evening Grosbeak calls on my iPhone. The bird in the box in my car responded before those in the wild did, but finally I called in two or three and opened the box. The grosbeak instantly flew off into the trees toward them. I wanted to take some happy photos, but he was hardly going to sit out where I could see him—I’m sure the poor guy had had enough of people to last a lifetime. Fortunately, even if he didn’t realize it, his lifetime was going to last a lot longer thanks to a few good people.

Evening Grosbeaks were once abundant up here, seen in Duluth backyards year-round, and even more abundant in wilder parts of the North Woods. But they’ve declined dramatically. I had a small flock in my own yard in August and September 2011, but none since, and I’d gone several years without them before that, too. As Minnesota and Wisconsin reconsider the species designated endangered or threatened, I wish they’d add Evening Grosbeaks, because the decline is troubling, the reasons behind it elusive, and research is needed to reverse the trend. 

Saving one bird at a time isn’t an effective way to restore populations, but each Evening Grosbeak is a valuable individual in its own right as well as an increasingly significant fraction of the total population. The joy I felt sending this one off was intensified by his focus on getting away. Wildwoods Rehabilitation Center restored him to health, and he’ll live out his days in the wild woods where he belongs.

Wednesday, March 6, 2013

Boreal Owl Update

Boreal Owl
Boreal Owl

During the three decades I’ve lived in Duluth, several winters have been marked by irruptions of northern owls. When I first moved here, seeing these extraordinary birds filled me with wonder and delight. I vividly remember going up Lester River Road with my husband and first baby to see my lifer Great Gray Owl perched on a low fence. When its eyes met mine, I felt an electrical surge of joy. That’s also how I felt when I saw my first Boreal Owl along a wooded country driveway in Saginaw.

When I became a wildlife rehabber in 1987, people started bringing me emaciated and dead owls. Northern owls leave their normal breeding range when driven off by competitors or when food supplies dwindle dangerously—a regular occurrence because they rely on prey species with population cycles that fluctuate wildly between high and low numbers. Their primary food resources are cyclical, so populations of these northern owls are cyclical, too, irruptions occurring when peak populations are about to drop precipitously. It’s not that the owls moving south are necessarily doomed. David Evans keeps track of Snowy Owls in the Duluth-Superior area. Some of his banded birds have returned several years running. But birds wandering beyond their familiar environment are subject to higher levels of mortality than those remaining on their home turf. Boreal Owls new to an area may not be able to find an unoccupied cavity to hide out in during daytime, exposing them to harsh weather and attacks by aggressive jays, crows, and hawks. They may not know the habits of unfamiliar prey species nor recognize the best hunting areas on unfamiliar turf. Tragically, lack of success in one area—the trigger sending them wandering in the first place—makes them hungrier and weaker by the time they reach new areas. By March in irruption years I’m often inundated with phone calls from people distraught after finding a dead or dying owl in their yard.

People who haven’t spent decades watching the dark side of these irruptions can’t help but feel the same joy when they see their first Boreal or Great Gray Owl that I felt when I saw mine, and I can’t help but share their joy at these thrilling encounters.

This year I’ve received calls and emails from hundreds of people enjoying thrilling sights of Boreal Owls between Duluth and Two Harbors. Social media have made it all surreal. Sometimes 20 or more people have crowded along the side of Highway 61 or the Scenic  Highway, binoculars, spotting scopes, and cameras all directed at a tiny camouflaged mite in a tree. Boreal Owls usually hunt at night. When one is desperately hungry enough to be hunting by day, a pack of acquisitive birders can be distracting, may scare prey away, or may attract the attention of potential enemies. But birders witness the little owls successfully capturing rodents and shrews, too, and these birders’ unadulterated joy is contagious.

Boreal Owl
This owl held its left foot up part of the time, making me suspect a foot injury.
Except for my trip to Two Harbors on the day I call Superb Owl Sunday, I didn’t have the stomach to look for owls this year. As thrilling as our experience was, the Boreal Owl Russ and I saw seemed to have an injured foot, which made me worry about its long-term prospects. The next day some people retrieved one on the highway just south of Two Harbors, which I suspect was mine. It is recovering nicely at the Raptor Center—what I thought was a foot injury turned out to be a broken toe. That bird, mine or not, will be released soon. But the same day I found out about that, I looked out the window to find a dead Boreal Owl in my own backyard. The DNR is collecting carcasses to send down to the Field Museum in Chicago, so the tiny body is bagged with the necessary information in my freezer, and my own feelings about this year’s owl irruption have chilled considerably. 

The intensity of these events—both the joyful excitement and the heartfelt sorrow—is more than I can bear. By next month the surviving owls will wend their way back to their normal range. They’ll once again be out of sight, but not out of my mind. I’ll breathe easier thinking of them leading their lives in secluded privacy, where the woods are lovely, dark, and deep, far from the madding crowd.
Boreal Owl

Tuesday, March 5, 2013

Chickadee Day!

Black-capped Chickadee
Black-capped Chickadee
Every year since 1975, I’ve celebrated March 2 as “Chickadee Day,” marking the anniversary of my seeing the first bird on my life list. My backyard chickadees always help me celebrate, and the celebration is even sweeter in years when I’m well supplied with mealworms, because one by one, my chickadees alight on my hand for them, and I get to appreciate all over again just how genuinely unique each individual chickadee is.

Chickadees appeal to me on many, many levels. I love them as I love all wild birds, as members of a unique species with wonderful physical and behavioral adaptations, and as individuals to be reckoned with. But I also love chickadees as role models of how humans, as individuals and as societies, could be. Chickadees are the epitome of self-reliance. Each chickadee finds a good unoccupied roost cavity or excavates one entirely on its own, using that tiny but sturdy chickadee beak.

Black-capped Chickadee nest
Chickadee in its own excavated cavity
Even when temperatures plummet well below zero, each chickadee sleeps alone, except during the few weeks each year when adult females brood their young. Chickadees associate in flocks, each working hard to stock up on food resources. But no matter how hard chickadees work to build up their individual food stores, each allows other chickadees to raid its pantry when they need. Chickadees understand that individual initiative and hard work are essential, but also that luck plays a role for everyone. One extremely hard worker may fill every crevice of a birch tree with food that serves it and its flock for many seasons or years, and then out of the blue an ice storm takes down the tree. Chickadees don’t play the blame game or dismiss those facing misfortunes—you can count on each chickadee to both work its hardest and share its bounty.

As with most human societies, chickadee flocks are hierarchical in structure. The top ranking males and females are more assertive than lower ranking birds, and apparently have physical characteristics that help them assert their dominance. One researcher recognizes higher-ranking birds under UV lights because their feathers reflect more UV light than lower ranking birds. This may be a signal of which birds are better at furnishing themselves with good roost holes, better protecting their feathers from weathering, or may indicate which birds are most effective at procuring healthy diets, or in some other way indicate fitness. In fall, young birds joining a chickadee flock often raise their body feathers and hold their wings open, as if trying to appear larger, while working out their rankings.

Black-capped Chickadee peeking in my window waiting for mealworms
My chickadee peeking in to get my attention
  However chickadees establish their flock’s dominance hierarchy, seldom does an individual chickadee not respect it. One of my backyard chickadees alights on my window frame and peeks in, tapping on the window or hovering a few moments to catch my attention. That bird may be smarter or more resourceful than others, but when I open the window and hold out my hand, it waits while three or four higher-ranking birds get the first mealworms. Maybe in a year or two, that chickadee will rise to the top of the flock hierarchy, but it sees no reason to disturb the social order for a quicker meal even if its clever actions are what enable the entire flock to procure such nutritious fare. Every chickadee brings its own skills and gifts to the table, and all are valued. The dominance hierarchy assures a social order that benefits one and all equally. Which, really, should be the point behind human societies, too.

Chickadee being rehabbed at the Raptor Education Group, Inc.
This year my chickadee celebration was made even better by the fact that Marge Gibson’s wildlife rehabilitation center, The Raptor Education Group, Inc. of Antigo, Wisconsin, set free a rehabbed chickadee that day. Someone had found the tiny mite struggling in the snow and brought it to them with a broken wing. Under Marge’s expert care in this state-of-the-art facility, the chickadee was restored to its proper life in the wild. My Chickadee Day celebrations are, in the overall scheme of the universe, pretty meaningless. Giving a chickadee with a broken wing a chance at survival—now that is something truly worth celebrating.

Chickadee being released to the wild after being rehabbed at the Raptor Education Group, Inc.