Animal Navigation There and back again—how we all get around!

Duck’s Fly Moon Birds migrate this time of year Birds migrate this time of year 50% of birds migrate! 50% of birds migrate! You can see them fly across the moon You can see them fly across the moon –Yes, even in NYC Why do they do that?

Who Migrates?

Long Distances! Arctic tern: flies km Arctic tern: flies km From pole to pole! From pole to pole! 3-4 days flying nonstop, no eating, no resting 3-4 days flying nonstop, no eating, no resting Often fly at night to avoid predators Often fly at night to avoid predators

How do they know when? Season---daylength Season---daylength Changes hormones Changes hormones Internal clocks too! Internal clocks too!

What are costs of migrating? Energy (hey, birds eat 10% of their weight a day!) Energy (hey, birds eat 10% of their weight a day!) Weather Weather Water Water Predation Predation Night time, and most birds are “diurnal”. Night time, and most birds are “diurnal”.

Benefits? Food (we think they “fly south”, but they actually “fly north” for the food! Food (we think they “fly south”, but they actually “fly north” for the food! Safety: penguins don’t find food in Antarctica, they find fewer predators. Safety: penguins don’t find food in Antarctica, they find fewer predators.

How? Map: says where you are and where you need to go Map: says where you are and where you need to go Compass: gives you direction to go in to get there. Compass: gives you direction to go in to get there.

Example: NYC, Humans What map do you think of? Subway, real map? Your street? What map do you think of? Subway, real map? Your street? Say you need to head east---how do you figure that out? Say you need to head east---how do you figure that out? –Landmarks, streets, real compass?

Question: Where is east now? What was your first thought? What was your first thought? –Look out window, use your “gut”? -We will do an experiment to test that -Things I use: sun, landmarks. I’d have to go outside! -What do you use?

Now you are a bird, a youngster Birds migrate from Europe to East Africa Birds migrate from Europe to East Africa How do that their first winter? How do that their first winter? Scientist: moved a bunch of birds west of their normal “start” Scientist: moved a bunch of birds west of their normal “start” –Kids, ended up “west” at end. –Adults corrected –So, compass is innate (born in you) and map is learned!

Adults corrected the mistake!

What is the compass? Sky! Sky! Sun (Rises east) Sun (Rises east) Sunset (sets west) Sunset (sets west) Stars Stars –Rotate around North Star. So you learn North by watching!

Stars rotate in the night sky!

Want to figure out latitude? Look at the big dipper Look at the big dipper Look at the rightmost stars Look at the rightmost stars on the bucket Those are 5 degrees apart Those are 5 degrees apart Measure with your thumb Measure with your thumb Count down to the Count down to the horizon from north star!

Seriously… …hey, if you are ever on Survivor this will come in handy! …hey, if you are ever on Survivor this will come in handy! As will what you learn from the experiment we’ll do later… As will what you learn from the experiment we’ll do later…

Animals learn their compass! Animals learn (in the nest if you are a bird) where the sun rises and sets Animals learn (in the nest if you are a bird) where the sun rises and sets They also watch the night sky from their nests and learn North. They also watch the night sky from their nests and learn North.

Experiment: scientist “teaches” birds in a planetarium!

Magnetic Field—our friend the pigeon! Homing pigeons can sense magnetic fields Homing pigeons can sense magnetic fields Experiment 1 (seriously): scientists put magnets on their heads! Experiment 1 (seriously): scientists put magnets on their heads! Experiment 2 (seriously): scientists changed the direction of magnetic field with a hat on the pigeon’s heads! Experiment 2 (seriously): scientists changed the direction of magnetic field with a hat on the pigeon’s heads! Lo and behold: pigeons went the wrong way! Lo and behold: pigeons went the wrong way!

Maps? More complicated! You must learn it You must learn it You must store it You must store it You must remember it You must remember it You must update it You must update it Examples: magnetic, landmarks, sound, smell, highways (!!). Examples: magnetic, landmarks, sound, smell, highways (!!).

“Flyways” (sometimes over water!)

Our experiment: Dead Reckoning Basically this is “keeping track of your distance and your turns”, then adding them all together to figure out your “total displacement” Basically this is “keeping track of your distance and your turns”, then adding them all together to figure out your “total displacement” Some people are good at this. Some people are good at this. Some people---not really (like me!) Some people---not really (like me!)