Wildthings Wildlife Rehabilitation Center

Migration Mysteries

     Scientists and researchers have come up with lots of ideas on migration.  Heck, even as a wildlife rehabber I have a few observations of my own.  With everyone trying to figure out the mysteries of migration, the one thing we would agree on is that there are still lots more for us to know.   I thought it might be fun to cover some of the interesting things we do know about migration. 

    In the continental United States there are over 100 species of birds that migrate/move south for the winter.  Most of the time birds will fly south rather than fly over the Continental Divide to warmer states.  That is where the term "going south for the winter" came from, they really do fly south for the winter.  The bottom line is they live by their food.  If your yummy favorite bug diet is gone in Montana, then you need to go some place warmer to eat.  Plus that is a good excuse to winter in Mexico.

    There are four type of birds in your yard: The ones that summer with you, the ones that spend the winter with you (because you are warmer), the temporary ones (like migrating thru), then the permanent ones that you have year around.  After these catogories is where is starts to get personal.  There are as many variations of migration as there are birds migrating.

    Some, are altitude migrators.  There are lots of birds that just do an altitude migration.  Spend summer higher up then for winter go down from the mountains to where it is warmer to spend the winter.  This  Dusky Grouse Photopicture is of a Dusky Grouse.  Now they do it a bit different.  They come to the lower altitude for raising their kids.  Then when it starts to get colder they move up the mountains instead of down.  This is a good example of how each species is unique in their migration.  They may move as far as 1000 ft. vertically to eat conifer bearies in the winter.

Leap Frog migrants fly along stopping to eat and rest along the way, Fox Sparrow Photounless their over rival territories.  Then they hop over them (flying of course) and wait to touch down for food and rest until the area under them is safe.  So their migration pattern is like a leap frog, up, down, up down until they get to where they are going.  This is the way the Fox Sparrow (left) migrates. Not fly straight through non-stop like some other species.

   Turkey Vulture Photo                                                       I find it amazing that all the different species know where they are going.  And, that they all go to different vacation destinies.  Personally, I find that a very hard decision! 

Even the Turkey Vulture, knows he is headed to South America for the winter!

 Some Birds are non-stop flyers.  Some birds walk their migration.  Then their are birds that swim migration. 

 

 

Hummingbirds all go to a warmer climate for the winter.  These guys don't fly over the mountains, they fly down the side of them to their winter home.  Each species of them winter in a different local.  Hummer's also do a really cool thing called torpid.  This is almost a mini-hibernation.  If you have an early winter snow storm and you wonder what happened to your humming birds over night, they went to sleep.  When they go into the torpid state they can slow down their body's calorie need so that helps them survive.  The only problem is they can't do it for long.  So as soon as they can they have to bolt for warmer regions.  The males like to leave at least a week before females to stake out their territories.  Typical guy thing!  Only the males do territories, the females get claimed by the males when they get down their so they never have to set up their own territories.  If you ever wonder if you are going to have an early winter or spring?  Watch the Hummingbirds.  They are some of the first to bolt for warmer ground.

Common Poorwill Photo

The Nightjar family does different things each sub-species too.  The American Poor Will, which is in the Nightjar family does the torpid state, like the Hummingbirds.  Of course they put their own spin on it.  With 1/3 oz of fat they can live for apx 100 days.  So they dont migrate far.  They like to stay in the same area then if winter is bad, they sleep through most of it.  Then the Nighthawk, which is also in the Nightjar family, migrates between 2500 -6800 miles in his quest for bugs.  Hey, just another FYI on the Nighthawk; when the Nighthawk goes into a dive the way he positions his wings he does a loud growl noise.  It can easily be mistaken for a bear or something as loud as it is! 

Swainson

  The Swainson's Hawk has one of the longest migrations of all.  They start in Canada in the summer, then go to Argentina for the winter.  They migrate right down the middle of the United States.  

 Then the Artic Tern is another bird that is famous for his extra long migration.

Even though birds usually sleep at night a lot of them fly through the night when migrating.  And land birds can't put down in water so whatever water mass they are flying over they have to fly until land.

Well I hope you had fun while learning, because I had fun and learned some new stuff while writing this! 

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