The three deadliest threats to our native birds

An icy wind is whipping the tall pines behind our house. Thick snow shrouds everything living. And yet for birds the greatest threats to survival are not the arctic temperatures or lack of food, but man-made barriers.

Wind farms have been touted as one of the most important sources of green energy that may help save our planet from climate change, but are they also giant "bird blenders"?

Modern turbine towers can reach a height of 270 feet with rotors as wide as a football field.

Klondike wind farm in Oregon

Wind energy suffers from one great disadvantage: the best sites are far from the dense population centers of the Northeast and mid Atlantic states where it's needed most.

Setting up wind farms on the continental shelf along the North Atlantic coast would be one solution.  (See below Cape Wind)

When starting my Google search on wind farms the first study I ran across was about an off-shore wind farm in the Baltic sea published in Biology Letters in 2005. Danish researchers did a radar study, covering the first year of operation, of migrating geese and Eiders negotiating their way through the forest of wind turbines.

Black lines indicate migrating waterbird flocks, red dots the wind turbines

They found that the birds kept a safe distance from the turbines and were flying almost exclusively down the center of the corridors, giving the turbines wider berth at night than during the day.  At first I felt reassured but that didn't last very long.

Next I looked at a study of the notorious wind farm on the Altamont Pass in California, one of the largest  in the US. It was built before anyone studied its effects on air-borne wildlife such as birds and bats.

Because of its mountain-top location  it was having a devastating effect on raptor populations, esp. Bald Eagles, Red-tailed Hawks and Burrowing Owls, by generating a warm updraft that would sweep the birds right into the path of the turbine blades, slicing them in half or decapitating them.

Altamont Pass --- Aerial photo: Ian Kluft

This wind farm supplies enough electricity to power a city the size of San Francisco

According to one study as many at 1300 raptors die each year in collision with Altamont's 5400 turbines. Worse yet, it's built next to the world's densest nesting area for Golden Eagles.  This and much more is contained in this fascinating 12 min video by KQED Quest.

Since then much work has been done to mitigate the impact. In particularly one turbine, that stood on a hill by itself and was responsible for much of the slaughter, was dismantled. Turbine design has been altered so that the birds now tend to fly above the height of the turbines, though some experts say more studies are needed.

A British study of onshore wind farms found that most birds are not harmed during the operation of the turbines. There was a significant decline of bird population however during the construction phase, probably due to interference with nesting. Most migrating birds fly at an altitude of 150 to 600 meters, that is, above the height of the average modern wind turbine (about 100 meters).

Design of wind turbines has had a greater impact though on bat mortality. A study found that whereas the diameter of the turbine rotors did not affect migrating birds or bats, tower height though had a significant impact on bat mortality: the greater the height the greater the bat mortality, suggesting that migrating bats fly at lower altitudes than nocturnally migrating birds and that the newer larger turbines are reaching into that air space.

Construction of the first off-shore wind farm, Cape Wind, is scheduled to start this year in Nantucket Sound between Cape Cod, Martha's Vineyard and island of Nantucket. See white cross on map below.There was much controversy  about the economical benefits vs the detrimental impact on scenic beauty for property owners along the shore and yachtsmen on the sound. Little is known about  Cape Wind's effect on sea duck activity, especially on the most numerous species Long-tailed Ducks.

Window strikes are a different matter. Toronto is a deadly city for migrating birds. It's the first tall glass barrier birds face when coming south from the northern wilderness. FLAP - Fatal Light Awareness Program - a volunteer organization in Toronto - has been working diligently toward making windows safe for birds.

The owner of the most lethal building, Cadillac Fairview,(see above), was sued under the Environmental Protection Act.  Its mirror-like windows were responsible for the collision death or injury of more than 800 birds between March and Dec 2010. The owner was acquitted but only after covering the windows with a special anti-reflective film.

This puts Toronto building owners on notice that they may be held liable for killing birds. Because of the different political climate in the US this avenue would probably not be successful here, but not all is lost. There is one organisation that promotes innovative and  interesting building designs, the American Bird Conservancy. See image gallery.

Screen over windows

The Lights Out campaign by the Chicago Audubon Society means lights out in the upper stories of tall buildings during migration: 

"Tall buildings can save birds by extinguishing decorative lighting on the upper stories after 11 P.M. each evening and leaving lights off until daylight from August 20 to October 25. Birds migrate throughout these months. Tenants on the upper floors are encouraged to turn out lights or draw blinds after 11 P.M. These recommendations apply to all buildings of 40 or more stories, and to buildings of 20 or more stories that are isolated from other buildings."

Thirty American cities have joined FLAPS drive of turning lights off in tall buildings. Building owners in Manhattan started doing so in 2010 prompted by New York City Audubon.

Volunteer checking for dead birds in the morning. Ángel Franco/The New York Times

And for the home owner Bird Conservancy came up with translucent bird tape on windows that is easy to apply and doesn't appear to be too expensive.

Video about applying Bird Tape

Predatory Cats: I love cats, love their sleek gliding movements, admire their coiled spring-loaded body when ready to jump....... I used to own a rescue cat. He was in a crate at my vet's with printed sign "Last Day". I thought about it all day and waited to call until after closing. They answered their phone anyway, and so he ended up in my home. 

 I wanted to keep him indoors but it was next to impossible during the summer when I spent much of my life out on the deck. The cat would yowl behind the window in utter misery. The exhortation to keep cats indoors is easy to follow in city buildings without outside fire escapes, but almost impossible in the suburbs or country unless you confine yourself to four walls. So I let him out. When winter came I discovered that he was a real virtuoso in hunting and killing birds.  I stopped feeding them and did so for the next 14 years. But when he died I vowed to never adopt a cat again. 

Mortality by wind turbines or windows pales against mortality inflicted by cats.

Chart: Which kills more birds, cats or turbines? (Mother Jones)

In an article in the New York Times one scientist compared  house cats to gypsy moths and kudzu - they all cause major ecological disruption.

 Estimates of annual cat predation on US birds and mammals

It is estimated that cats kill between 1.4 and 3.7 billion (median 2.4 billion) birds a year with 69% of this mortality caused by un-owned cats. Un-owned cats kill about about 3 times the number of birds as owned cats.

Un-owned cats are those that have been abandoned by their owners, have escaped,  or are born as strays. The estimate of these cats range up to 70 million. A female cat produces about 2 litters a year with 4 to 6 kittens per litter. With these large numbers programs such as trap, neuter and release (video)  are ineffective. Many cats that are captured and brought to a shelter are in fact euthanized. 

Cats are an invasive species without natural predators. Where introduced they have wrought havoc on natural wildlife. They are easy to keep and easy to lose, since there are no leash laws, no license requirements, and no taxes on cat owners. Unlike dogs they can forage in the wild and sustain themselves on small mammals and birds. There is no opprobrium on owners who let their cats run wild,. and when they have kittens: who doesn't agree that kittens are cute!  Appealing to our emotions may be one of this species' evolutionary survival strategies. 

To save birds and other wildlife do we have to be ruthless in eliminating stray cats? This blogger is making a passionate argument for just trap and kill rather than trap, neuter and release, but that would be a losing battle, as a huge cat lovers grass-roots lobby would spring up instantly.

Do cats deserve greater protection than our native birds?

Protecting birds against their cats is left up to the cat owners. Here is what an individual can do to check their cat's predatory behavior: 

Put a neoprene Cat Bib (see video on website) on your cat, whenever the cat is outside.  It may look ridiculous, but please don't laugh! In a study it stopped cats 81% of the time from catching birds.

Or have your cat wear a colorful collar which makes the cat much more visible to birds though somewhat less effective than the bib. Here's a YouTube video.

Thus the three deadliest threats are wind farms, windows and wild cats, but cats are by many magnitudes the deadliest.  We as individuals can't do much about the first two, but must do something about the last, because there is no authority that will jump in and bear that responsibility for us.

Three authors: Birds up close and personal, and Magpie passes mirror test

For crows living in flocks fosters complex behaviors

Just when I was learning to read I found a book in our attic which promised to teach me the language of birds. It was torn in half though, and the half with the answers was missing. So to my great disappointment the language of birds remained a mystery.

That same desire underlies much of today's research about birds. Will we ever know how birds are seeing their world? how they interpret what goes on around them? or what they are thinking? Are they even conscious?

The sixteenth century French philosopher Descartes claimed that animals are automatons, that is, pure machines without consciousness. Many researchers still adhere to the view that animals are biological entities subject to inborn unalterable instincts, but as animal owners and caretakers have known all along this is not true for their pets, not true for farm animals, nor is it true for laboratory animals. On closer acquaintance we know that within the limits of their abilities they are all individuals, have different personalities, are bold, shy, curious, anxious, happy, moody, playful, sociable, gregarious or withdrawn... just like human beings.

The Bluebird Effect: Uncommon Bonds with Common Birds by Julie Zickefoose

If looking at the cover painting of Julie Zickefoose's The Bluebird Effect you think it's a picture book, you are mistaken. Yes, the author is an accomplished artist; she illustrates her book with exquisite  paintings and drawings, but her look at birds goes much deeper. In her work and writing she combines a human's lively empathy and warmth, a scientist's cool eye and a child's curiosity and wonder. She takes on the arduous work of a bird rehabilitator in rearing abandoned nestlings or injured birds. She takes on the impossible task, for example, of raising the chicks of  chimney swifts, blind and naked, only a few days old, dislodged perhaps by a chimney sweep. She gives them a home in a rattan basket where they can cling to the wall, the closest approximation to the inside of a chimney, keeping the area well heated to 8o degrees, blows on them to imitate the wing beat of the arriving parent,  nudging them to gape to be fed every 20 min, and keeping them hydrated with an electrolyte solution by eye dropper.

 She gives them names but they are not pets; she releases them back into the wild as soon as they indicate they are ready. The greatest reward for her is when one of her former charges recognizes her and, peeling away from its wild companions, lands on her shoulder.

Northern Cardinal fledgling

She is a terrific writer. This book would enchant and entertain any bird lover. It would be a great gift for budding birdwatchers and perhaps foster in them a passion for birding.

Gifts of the Crow: How Perception, Emotion, and Thought Allow Smart Birds to Behave Like Humans by John Marzluff and Tony Angell

Corvids, of which crows are a member, are exceptionally smart. According to the author they have much in common with us: language, delinquency, insight, frolic, passion encompassing wrath and grief, risk-taking and awareness. He devotes a chapter to illustrate each property with fascinating observations and stories. For example when caching food, crows are very aware of which particular bird is watching them. They may only pretend to cache and, when no one is looking, move  the cache to another place, but they only do so if they themselves have been thieves. Another example: observing a small flock of geese being tossed pieces of bread, crows quickly covered up each piece with a maple leaf, making it invisible to the geese, and saving it for themselves. This particular ability to know what another individual, even another species, is thinking is shared only by our closest primate  relatives. It's a complex cognitive property called possessing a theory of mind. They share with humans the ability to lie and deceive, to misdirect and prevaricate. They are the opposite of simple-minded. 

Pen and ink drawing by Tony Angell

Crows may come to the rescue of an injured flock member, or alternatively they may show aggression and rage, ending up killing disabled bird with their beaks. The author has various theories about what in the crow's brain could trigger such behavior, which chemicals or what neural events may be playing a role. Regrettably much of the book is taken up by these detailed discussions of the underlying mechanisms and pathways. 

Corvids appear to think a lot like us, but have arrived at this ability over different pathways, that is, by convergent evolution.  I found such discussions interesting only to the extent that I learned that bird brains have a very different architecture from mammalian brains.  Perhaps the authors felt the need to buttress their anecdotal observations with a scientific foundation. Most readers will probably find this arrangement distracting. I skipped a lot of it. 

But still, it was fascinating to read about their complex behaviors demonstrating calculation, aforethought, planning for the future, playing tricks, and even showing gratitude in giving token gifts to humans who have treated them kindly.

So, when glancing at a crow it's tantalizing to think that there's an intelligent being looking back at you. We always wonder how animals can be so much like us. Maybe we should turn it around and wonder how much we are like animals, or how little separates us from animals. We are smart, we can figure things out but, like our avian relatives, it's our emotions, much more so than intellect and reason, that make us who we are.

American Crow on picnic table

Darwin in The Descent of Man wrote:

"The difference in mind between man and the higher animals, great as it is, is certainly one of degree and not of kind. We have seen that the senses and intuitions, the various emotions and faculties, such as love, memory, attention, curiosity, imitation, reason, etc., of which man boasts, may be found in an incipient, or even sometimes in a well-developed condition, in the lower animals."

There's an interesting PBS Nature Video "A Murder of Crows" (about 40 min) on the author's research on crow's facial recognition, and how they pass on any bad experiences to flock members and offspring.

The European Magpie is believed to be one of the most intelligent of all animals

The mirror test is the ability to recognize oneself in the mirror. A mark is attached to an area invisible to the animal's eye, but clearly visible in a mirror catching the animal's attention. Until now only three species have demonstrated this self-awareness: apes, Asian elephants, and bottlenose dolphins.  In 2008 the first non- mammalian species was added to this list: the European Magpie (Helmut Prior, Goethe University, Germany)

Magpie in mirror test (newscientistvideo approx 60 sec)

The deeper we dive into animal intelligence, the more complex it becomes.  We have finally gotten beyond looking at  animals as mere biological mechanisms.   We test them and are astonished to find that they can count, determine the difference between classes of objects, are able to predict another bird's mind, detect faking and misdirection. These abilities are as useful in their world as in ours; so it's not that surprising that they resemble us in many ways.

The AlexStudies: Cognitive and Communicative Abilities of Grey Parrots – by Irene Pepperberg

If you want to get an inside view of what it takes to unlock a bird's intellectual powers you should read Irene Pepperberg's book "The Alex Studies" which describes the experiments designed to explore an African Grey parrot's ability to grasp  such abstract concepts as color, shape and material. The author acquired him at age 1 and kept him in her lab until his premature death. During his life he followed a grueling schedule of lessons lasting of  8 to 12 hours a day.  A Grey parrot's life expectancy is about 60 yrs. So his sudden death at age 30 came as great shock. An autopsy failed to reveal clues as to the cause. After reading this book though I wondered whether he died perhaps of boredom? of  loneliness? lack of companionship, lack of physical closeness and emotional attachment to other members of his species? ------But maybe not. Read on:

Alex &Me: How a Scientist and a Parrot Discovered a Hidden World of Animal Intelligence--and Formed a Deep Bond in the Process -- by Irene Pepperberg

In this book the author recounts Alex's life from a personal perspective as she struggles to find appropriate lab space and grant money. She also struggles to have her research recognized. That in part determines her relationship to the bird: an emotional attachment to the subject of her study would rob it of its credibility.

She usually had a number of assistants working with Alex. He learned quickly how to manipulate them for extra treats. In fact he played the boss in the lab, often strutting around like a little Napoleon, giving orders to all and sundry.  He liked to play tricks such as shouting out wrong answers to a younger parrot who was being trained nearby, or wolf-whistle at male students walking through the lobby. He grew close to one assistant in particular, calling him by his name and running up his arm to perform the Grey's mating dance. But when the assistant had to be away for three months, Alex felt abandoned and never forgave him. Upon his return he never spoke to him again.

Fleshed out by countless observations and anecdotes Alex becomes a fully rounded character. His achievements and personal quirks are celebrated in newspaper stories and at fundraising events. He gains such world-wide renown that when he dies letters of condolences from fans around the world flood into the lab. Along with such luminaries as Ingmar Bergman, Luciano Pavarotti, and Lady Bird Johnson, he even merits an obituary in the Economist. 

Meet Alex in person: Nova Science Now video ( ~ 12 min long)


(This is a re-post of my February contribution to Birding is Fun on 2/6/13)

Birds in Winter

The other day I was surprised to see a flock of about 20 American Robins feeding on the hairy red fruits of  the Staghorn Sumac that was growing behind our shopping center. Because the fruits are dry, have little flesh, no fat or sugar they are usually left untouched until late winter. In spring and summer we are used to seeing them foraging on the ground, running, then suddenly stopping to listen and pouncing to extract an earthworm. In the winter when the ground is frozen they switch to fruit on the ground or still hanging in the trees. 

The Robins we see here in the winter probably probably started their fall  in Canada and found the Northeast temperate enough to stay through the winter, whereas those that summer with us have shifted southward. So these are probably the same Robins we see in early spring when the snow is receding,  in transient large flocks foraging among the old grasses and leaves in our backyards and fields.

Many birds that are solitary during the breeding season often flock together in winter, when food sources are rare and much more sporadic. Even through the bounty must be shared with a larger number it still pays off to have more eyes scouting for them.

Snow Buntings are highly territorial in the summer, jealously defending their nesting sites in the tundra, but during the winter they often travel in mixed flocks with Horned Larks. They are most easily found along plowed roadsides where they forage for grass seeds and grains.

Snow Buntings crossing a paved road

Flock of foraging Snow Buntings and Horned Larks

Male Horned Larks

Both the Horned Larks and Snow Buntings roost in scrapes in the ground or burrow into the snow for extra protection against the cold. During a storm they may let themselves be snowed in. 

In the winter Northern Shrikes, like this first year juvenile, migrate south from their home in the tiga/tundra to southern Canada and the northern United States where prey may be more available.  Sitting high in a tall tree they look innocuous, watching and scouting for any small movement in the trees or on the ground, when they are down in a flash to grab a bird or small mammal, revealing their true nature and justifying their Latin name Lanius excubitor "Butcher Bird".

House Sparrow puffed up against the cold trying to keep warm.

Bohemian Waxwings are true  nomads, roaming in flocks  and descending when finding berry or fruit bearing trees. They are voracious eaters and only leave when all the fruits have been consumed. They are so unpredictable that It's always a special thrill to see them. 

They cheer me up with their jaunty masks and feathered caps, the red wax tips on their wings and the red untertail coverts. Here they are feeding on fruit fallen off a crap apple tree. 

Their rakish looks make me smile.

Homely looking Wild Turkeys foraging on a manure pile in a snowy field.

I first saw this Common Raven on the flat roof of parking garage. It then flew across the parking lot and landed on a  mound of snow at the edge of the lot where I followed it in my car. I was able to take a couple more photos before it flew off heading east into the morning sky.

Happy Birding in 2013!