5 Things I Learned about Migratory Birds from Rebecca Perkins Hanissian

In a short article written for Northern Woodlands as part of their “The Outside Story” collection, Rebecca Perkins Hanissian ponders her relationship to migratory birds. Specifically, she notices the evolutionary traits she may have in common with birds.  Besides this being a humorous read about human behavior, this article identified a five avian adaptations worth sharing.

Chickadee on branch with snow Photo by Erik Karits on Pexels.com
Photo by Erik on Pexels.com


Zugunruhe is a German word that means “migratory restlessness”.  In birds, this refers to the increased activity that happens during the spring and the fall.  Scientists believe that this “restlessness” is brought on by internal and environmental cues such as the length of day and hormonal changes.


Hyperphagia is basically overeating. Birds typically engage in hyperphagia prior to their migration periods.  Overeating allows them to store up energy for their long migratory flights.  The graph below from American Scientist shows the relationship between hyperphagia, or fattening,  and migration.(3)    

Bird behavior graph
Image Credit: AmericanScientist.org


The graph above also shows the molting period for migrating birds. 

Bird feathers are made up of the same substance as human hair and nails: keratin.  This is important because it means that feathers, much like hair and nails, cannot repair itself.  Instead, worn or damaged feathers need to be replaced. The process of replacing feathers is called molting.

In order to keep the flight feathers in top form, birds often molt prior to migration.  Molting takes a fair amount of energy so it usually occurs prior to the fattening period.  You will notice in the graph  that molting and fattening are overlapping in the spring but separated out in the fall.  My suspicion is the difference is a result of the availability of food in the summer and the influence of the breeding season.

It should be noted that not all birds molt at the same time or at the same rate.  Some birds such as chickadees only molt once a year, where as marsh wrens molt twice.(4)


Thermoregulation is the scientific word for behavioral and physiological traits that are used to help regulate body temperature.  Birds who spend the winter in colder climates can grow up to 25% more feathers to help them insulate their bodies.(1)  However the unfeather parts of their bodies, such as their feet and legs, can’t benefit from these extra feathers. Instead they are able to constrict their blood vessels and limit the blood flow into the feet which will reduce heat loss.  This process is called vasoconstriction.

Not all migrations are equal

Not all birds migrate. But those that do migrate, don’t all travel the same distance.  Bird migration can be separated into short-distance, medium-distance, and long-distance.(5)

Short-distance migration may look like a bird traveling from the mountainside to the lower plains, or from one hunting ground to another.

Medium-distance migration usually falls within a couple of hundred miles. 

Long-distance migration can be several hundreds of miles.  For example, the broad-winged hawk migrates about 4,300 miles from New England to South America. 

Hannissian did a wonderful job highlighting the fact that humans might share some of the same behaviors as birds.  She mentioned that she eats more in the fall and winter (hyperphagia), she often dreams of going south and becomes restless when trapped inside (zugunruhe), and practices thermoregulation by putting on her down coat.  Her essay really makes me wonder, that despite our best attempts, we really aren’t that different from the other-than-human species that share this planet.

You can read Hanissian’s full article here

Sparrow in winter:Photo by Rahime Gu00fcl on Pexels.com
Photo by Rahime on Pexels.com

The Outside Story” is a series of ecological articles written for Northern Woodlands and subsequently found in newspapers of Vermont and New Hampshire since 2002.  Learn more by going to NorthernWoodlands.org


  1. Rebecca Perkins Hanissian: “To Go or Not to Go? How Birds Weather Winter”, Northern Woodlands
  2. Dr. Maria Wheeler-Dubas: #bioPGH: Zugunruhe!, Phipps Conservatory and Botanical Gardens
  3. Americanscientist.org: Avian Migration 
  4. AllAboutBirds: The Basics, Feather Molt. 
  5. AllAboutBirds: The Basics Of Bird Migration

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7 thoughts on “5 Things I Learned about Migratory Birds from Rebecca Perkins Hanissian

Add yours

  1. Two things –
    Blue Jays migrate west to east, east to west, not north.south.

    In Virginia, we have residential Canadian Geese. They are supposed to go north, but because people feed them, they stay. So a lot of money is being spent to get them to migrate.

    1. Interesting about blue jays. They are one of the few birds that stay around here during the winter. I have no idea if they trade locations with other blue jays. I will check with the local ornithologist! That is fascinating!

      As for the geese, why migrate when the food is easy to get where you are.

  2. Fascinating info, Mark. Wintertime always brings to mind chickadees (which I’ve always referred to as snow-hoppers). I’d look out the kitchen window at the farm and see the backyard peppered with those little bobbing black heads as they pecked at the snow. One bizarre migration scene I witnessed once was a flock of seagulls (no kidding) a few miles from the farm in southeastern Utah. Yep, seagulls. There’s a large population of gulls in northern Utah at the Great Salt Lake and Utah Lake (the seagull is Utah’s state bird, which is a real head-scratcher but it’s due to religious pioneer reasons), but to see them so far from any large body of water flying across southeastern Utah was just surreal. One common scene at the farm was seeing Canadian geese in the wheat field during migratory periods. My mom always got a kick out of that. Thanks for yet another in-depth and well written essay, Mark. 🙂

    1. Hi Mike, Were you just trying to find a way to add in an 80s band reference?!
      But seriously, I didn’t know that about seagulls being Utah’s state bird. That is pretty fascinating. The Canadian geese are a common sight where I live. There has been a small group of them living on the edge of the neighbors property for the past couple of years. It is good to see them hanging around the pond.

      1. Hee hee, it wasn’t an intentional ’80s band reference, but let’s just say I was definitely aware of it when I wrote that post! 😀 To go along with your Hares and Rabbits post, there was an ’80s rock band named Wrabit. They released three albums. I have their first one on vinyl and really liked it. ’80s band references FTW! 🙂

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