Bird Sleep

 

Just after sunset, with fading light and falling temperature, wave after wave of Canada Geese circled our cove and gracefully landed.  They joined a raucous flock of geese, perhaps 500 or more, apparently judging the cove to be a safe haven for the night.  But with all the honking I wondered if any, myself included, would ever be able to fall asleep.  With darkness, however, they did quiet down, except for the occasional honk from a vigilant sentry goose proclaiming all is well.

Canada Geese, Branta canadensis

As one ages sleep patterns become an issue, and sometimes even a topic of conversation and concern.  Being a curious birder I decided to do a little research, emphasis on little, as to the sleeping habits of our feathered friends.  What’s their sleep pattern, how much do they need, where do they go at night, can they sleep while flying, etc.?  I also scanned my photo archives looking for pictures of sleeping birds.  Unfortunately I usually delete pictures of birds with their eyes closed, but did find a few suitable for this post.

Eastern Screech Owl, Megascops asio

On my bedside nightstand there is a fascinating book by Matthew Walker entitled “Why We Sleep”.  It’s mostly about humans but does include a great chapter about the evolution of sleep.  According to the author a biologic sleep requirement must have evolved very early, as all animals, even insects, demonstrate sleep cycles.  You can confirm this with the characteristic brain waves on the EEG’s of sleeping animals and by periodic cycles of non-arousal of small insects.

Yellow-crowned Night-Heron, Nyctanassa violacea

Although all animals require some sleep, the amount and style vary considerably.  Walker states that the length of the restorative sleep requirement is determined by the complexity of the animal’s nervous system.  Both the length and type have evolved separately for every species and are balanced by the equally important need for wakeful hunting, eating, nest-building, and blog writing.

Dunlins, Calidris alpina

We are all familiar with the two types of sleep, REM and non-REM, identified by their characteristic brain waves.  It’s interesting that REM, the shallower sleep stage associated with dreaming, only occurs in mammals and birds.  It is, therefore, a later creation in the evolutionary sequence.  I consider it an “eye opener” to think of birds actually dreaming.

Common Nighthawk, Chordeiles minor

Although there are similarities between avian and human sleep, there are also many differences.  Birds demonstrate hemispheric sleep, the amazing ability to let half the brain sleep while the other half stays wide awake, perhaps as a defense for lurking predators.  At some point this split reverses and the other half falls asleep.  It’s interesting that this hemispheric sleep only occurs with non-REM sleep; REM for some reason, requires total brain participation.

Barred Owl, Strix varia

Frigatebirds are amazing seabirds that can stay aloft without landing for up to two months.  They have one major deficit–they cannot swim.  If forced to land at sea they quickly become water-logged and drown.  So curious Niels Rattenborg and others from the Max Planck Institute for Ornithology figured they would be the perfect bird to evaluate for in-flight sleep.

Magnificent Frigatebird, Fregata magnificent     photo by A. Sternick

Rattenborg fastened EEG leads to the skulls of 15 frigatebirds and attached a device to monitor flight speed.  The study confirmed that birds do indeed sleep while flying, but not in the expected manner.  They slept only in short bursts of 10 seconds and only for a total of 45 minutes each day, a much shorter duration than their sleep cycle on land.  They also only used hemispheric sleep while flying, and only slept while gaining altitude in a thermal.  They were completely awake and alert in every gliding descent, perhaps to avoid a lethal crash landing at sea.

Black Skimmers, Rynchops niger

Birds assume many different sleeping positions on land, but I’ve not yet seen one on its back with feet pointing heavenward.  Shorebirds sleep standing up, often on one leg, and usually facing into the wind.  Night herons, owls, and woodpeckers sleep  perched upright.  Their leg muscles in a relaxed state result in a clenched claw, firmly grasping the branch.  Many birds such as the nighthawks sleep horizontally, while some parrots sleep hanging upside down in a bat-like manner.  Many cavity nesters seek out a vacant cavity for the night.

Bonaparte Gull, Larus philadelphia

Birds, like humans, are susceptible to sleep deprivation.  Walker reports that the U.S. government has spent millions investigating the sleep pattern of the lowly White-crowned Sparrow.  If you deprive this bird of sleep during the season it would normally be migrating, it experiences no ill effects.  But similar sleep deprivation at any other time results in catastrophic physiologic brain and body dysfunction.

White-crowned Sparrow, Zonotrichia leucophrys

I’m not sure how they deprived the little bird of sleep; perhaps with bright lights and continuous Barry Manilow songs at high volume.  In any case, this bird has apparently evolved some protective mechanism for sleep deprivation that the U.S. government would love to uncover.

Black-crowned Night-Heron, Nycticorax nycticorax

Have you noticed how difficult it is to sleep the first night in a new hotel and bed?  I now believe this is a throwback to my evolutionary past.  Is there a Sabre-toothed Tiger lurking in the bushes or a Wooly Mammoth lumbering past my cave?  Just like the birds I require safe sleep, but haven’t yet mastered that hemispheric trick.  I guess I need that sentinel goose, standing guard and signaling all is well.

Christmas Birding in the City

 

Northern Cardinal, Cardinalis cardinalis

 

City sidewalks, busy sidewalks

Dressed in holiday style

In the air there’s a feeling of Christmas.

Children laughing, people passing

Meeting smile after smile

And on every street corner you’ll hear

Silver bells.

 

Strings of streetlights, even stoplights

Blink of bright red and green

As the shoppers rush home with their treasures.

Hear the snow crunch, see the kids bunch

This is Santa’s big scene

And above all the bustle you’ll hear

Silver bells.

by Ray Evans & Jay Livingston

 

Boston Common

This was my Mother’s favorite Christmas song.  I remember her sitting at the old Chickering piano in the sunroom, belting out these lyrics as if it was yesterday.  I live in the country now, just outside a small town of a few thousand, with elbow room, trees, tidal wetlands, and only a rare passing car or visitor.

Blue Jay, Cyanocitta cristata

In the past we’ve had a house full of extended family celebrating the holiday, but those times have passed.  Understandably children and the grand-child are making their own traditions in their homes and we are welcomed and eager to be part of “Santa’s big scene” in the heart of downtown Boston.

White-throated Sparrow, Zonotrichia albicollis

Their high-rise apartment looks down on the city streets blinking red and green, the frozen Charles River, and a small sliver of the snow-covered Common.  Their tree is a real spruce and adorned with ornaments, many of which are familiar from Christmases past.  Outside soaring gulls fly by our windows while the urban House Sparrows stay much lower on the sidewalk among the shoppers and bunching kids. The skaters crowd the Frog Pond ice, while the Nutcracker is playing at the nearby Opera House.

Opera House

One cold dawn, two days before Christmas I broke away for birding at Mount Auburn Cemetery.  I’ve previously described this birding hotspot in several posts (2/4/2015, 11/11/2016, and 4/20/2018), but this is my first visit in the winter.  In spring and fall it is a migration trap for weary travelers; a welcomed oasis of green and water amidst the urban sprawl.  It’s also the home of year-round residents, including a Red-tailed Hawk perched atop the local food chain.

Red-tailed Hawk, Buteo jamaicensis

A subway and bus ride took me to the north entrance of the cemetery.  The central “mountain” of Mount Auburn has shaded its northern side with crunching snow and ice covering the grave sites, pathways, and roads.  A sign cautioning to proceed at your own risk tried to warn me away, but to no avail.  It was a risk worth taking.

This birding site is one of my all-time favorite locations.  The birds were just the predictable, common species, and quite sparse on that cold morning, but sometimes birding is not just about the birds.

All the ponds were frozen solid.  I saw an adventurous squirrel skate across one, but there were no ducks or geese.  The deep dark glen, a sanctuary for countless birds in warmer weather was now cold and silent, except for the occasional raspy cry of a jay.

The cemetery compels one to quietly reflect on the years gone by and those still to come.  The stones mark many lives well-lived, and perhaps some, not so much.  I was happy to be there and see the nuthatches, robins, and sparrows, but also to leave the burying ground behind and rejoin the Christmas bustle.

Christmas Eve found us in a long line of revelers, waiting on cold Copely Square to enter the warmth of the magnificent Trinity Church.  Our seats, almost in the front row, gave us a great proud view of our grandson in the choir, as we all joined them in singing the Christmas favorites.  The soaring soprano descants brought us chills and the deep bass notes of the organ shook our seats and stirred our souls.  Music like this makes the sacred season for me.

Trinity Church

Christmas in the city with the family, great food, wine, and song–I think I can get used to this.

In the bleak mid-winter, frosty wind made moan,

Earth stood hard as iron; water like a stone;

Snow had fallen, snow on snow,

In the bleak mid-winter, long ago.

 

What can I give Him, poor as I am?

If I were a shepherd, I would bring a lamb;

If I were a wise man, I would do my part;

Yet what I can, I give Him–give Him my heart.

by Christina Rossetti