Nature's Starhoppers

[SaberScorpX]

Excerpt from the Zoological Society's link on migrating birds:
http://www.zoosociety.org/Conservati...ationFacts.php

"Night flyers use celestial navigation, which means they find their way by
knowing the patterns of the stars in the sky, and by knowing special stars like
the North Star. In their first year of life, birds memorize the position of the
constellations in relation to the North Star. These star patterns stay the same
even though the Earth moves through space, making the constellations appear to
move to different spots in the sky during the year."

I'm imagining the more adept feathered starhoppers flaming other birds for
relying on their nests' Go-To system

SSX

[Jon Isaacs]

>

Its pretty hard to imagine that birds can do this, personally I am a doubting
Thomas. They make all sort of claims, migrating by magnetic fields is another
one.

On the other hand, there is some explanation because they seem to be able to do
it year after year and banding studies indicate many species do it with amazing
accuracy...

Some Hummingbirds migrate across the Gulf of Mexico from the Yucatan to the
gulf coast of the US, all in one shot, lifting off at a body weight of 5 grams
and landing at 3 grams. This flight takes over 24 hours and their continuous
specific power output would be like a normal man putting out 8 horse power....
Pretty amazing little creatures.

So, its pretty hard for me to fathom that birds navigate via the stars, but
they do fly at night and they do seem to get there year after year....

I guess I'm just a bird brain...

jon

[Florian]

>Its pretty hard to imagine that birds can do this, personally I am a doubting


I remember a demonstration i saw on TV years ago. Was probably on NOVA. A bird
was put in a cage in a planetarium. On the bottom of the cage was a stamp
pad and surrounding it was a ring of white paper. The lights were turned
off and the star projector was turned on. The bird hopped consistently
in a certain direction. The neat thing was when the stars were rotated
around the dome the bird's hopping would rotate as well! At least that's
how i remember the demonstration going. Seemed to me pretty conclusive that
the bird was getting his directional clues from the stars. I don't remember
what type of bird it was.

-Florian

[Alexander Avtanski]

Florian wrote:


This and others experiments are described in the book "The minds of birds"
by Alexander F. Skutch. Very nice book, contains tons of interesting info,
highly recommended.

- Alex

[Richard DeLuca]

In article <cji1lu01867@news2.newsguy.com>,
"Florian" <Florian@remove.stargazing.com> wrote:



Many years ago, there was an article in S&T about a planetarium
experiment with Indigo Buntings. You may be describing the same study.
As I recall, the planetarium was a small one at some college, and the
Buntings consistantly used the north star and maybe even the circumpolar
constellations for orientation.

Starry Skies,
Rich

PS: I enjoy your observing reports!

[SaberScorpX]

this from:
http://www.npwrc.usgs.gov/resource/o...tio/orient.htm

"Using the artificial night sky provided by planetariums demonstrated that
nocturnal migrants respond to star patterns. Quite analogous to Kramer's work
on solar orientation, Franz Sauer demonstrated that if the planetarium sky is
shifted, the birds make a corresponding shift in their orientation azimuth.
Steve Emlen was able to show that the orientation was not dependent upon a
single star, like Polaris, but to the general sky pattern. As he would turn off
more and more stars so that they were no longer being projected in the
planetarium, the bird's orientation became poorer and poorer. While the proper
direction for orientation at a given time is probably innate, Emlen was able to
show that knowing the location of "north" must be learned. When young birds
were raised under a planetarium sky in which Betelgeuse, a star in Orion of the
southern sky, was projected to the celestial north pole, the birds oriented as
if Betelgeuse was "north" when they were later placed under the normally
orientated night sky, even though in reality it was south...
Considering the array of demonstrated and suggested cues that birds might use
in their orientation, it is clear that they rely upon a suite of cues rather
than a single cue. For a migrating bird this redundancy is critical, since not
all sources of orientation information are equally available at a given time,
nor are all sources of information equally useful in a given situation."

SSX

[Clif]

saberscorpx@aol.com (SaberScorpX) wrote in message news:<20040930171408.10414.00002946@mb-m23.aol.com>...

However they do it (and using star positions is a likely method)
they learn it
from their parents, it is not instictual. We have a huge population
of "Canada"
Geese who live year-round in New Jersey. Every fall they form
themselves into
the familiar chevron formations and fly about aimlessly for a while,
and then
settle back down on a golf course, corporate park, or suburban
development
lawn, never having left the neighborhood. It is clear that they have
no idea
which way to fly. Evidently, after a couple of generations of living
in NJ suburbia
there's no one left who knows how to fly south.
A similar case is the sand hill crane. There's a movie about a
guy who rescued
a bunch of sandhill chicks. When it came time to migrate, he taught
them
where to fly by taking off in an ultra-light plane and leading them
south. They
followed him because they had imprinted upon him and considered him
their dad.
In this case, the navigation must have been solely by landmarks since
he only
flew in the daytime. I sure wish there were a way to convince all
these NJ geese
to follow someone south. I would even be happy to teach them
constellation
identification...
Clif

[Robert Cook]

jonisaacs@aol.com (Jon Isaacs) wrote in message news:<20040930174601.24078.00001480@mb-m13.aol.com>...

I'm a skeptic by nature, but I don't find something like this
inherently difficult to believe at all. It would simply be an
instinct and mental capability that they evolved, much like the human
capability to acquire language. If there can be natural forms of CCDs
and sonar, then why not natural compasses or "natural GPS" via the
stars?


It's certainly not an accident, one way or another, and remember that
they have variable winds with which to contend. The one thing I would
find difficult to "swallow" (pun intended) is a ton of landmark and/or
constellation data being encoded in their genes. However, what they
do have, almost undoubtedly, is a notion that they've got to go in
some direction at some time, along with a capability to learn how and
when to get there. I'm not sure whether that's more or less amazing
than bees doing their little dance to give directions, although birds
do have more inherent potential, in any case.


Most birds have fairly poor night vision, and many migrate over large
bodies of water, so this probably rules out landmarks for many
species. Celestial and magnetic navigation seem to be the most
plausible theories--certainly more so than magic or "they just know,"
for example. :-)


If you're talking about parrots' brains, then that's a compliment.


- Robert Cook

[ultralightbackpacker@ihatespamyahoo.com]

>>

That was going to be my point as well. the big city birds would never
be able to make out any stars or even constellations because of the
light pollution leaving them marooned in the city. I remember reading
somewhere that pigeons actually find there way hom via roads,
following the roads from above. Anyway,

[Tom Rankin]

I'm skpetical of the 'stupid bird' theory.

Have you banded any of these birds and studied them for a few years?

More likely to me is the 'lazy bird' theory. Clearly, they have enough
food to survive in New Jersey. So why migrate further south?

Now, is it true that large flocks of Canada geese in more northern
cities do the same thing ?

Clif wrote:

We have a huge population

--
Tom Rankin - Programmer by day, amateur astronomer by night!
Mid-Hudson Astronomy Association - http://mhaa.whodeanie.com
Views and Brews - http://viewsandbrews.com

When replying, remove the capital letters from my email address.