New
Kids on the Block: Claiming a Territory
Video and Viewing Guide
Background
A
Male Robin's First Summer
Imagine
you are a male robin who hatched last April. Now it's March
— almost your first birthday. You’ve been hanging
out with other robins for your whole life. Your brothers and sisters hatched
right around the day you hatched. You were always eager to be fed first,
but except for trying to beg more insistently than they did, you didn’t
squabble or fight with them. When you fledged from your nest, you stayed
with your brothers and sisters and father for a few weeks. Each evening,
your father led all of you to a big stand of trees where you’d sleep
with lots of other robins. When your father got busy with new babies,
you remained with your sisters and brothers, and joined other young robins
in small flocks. Every night your father — and soon a whole new
batch of young robins — joined
you in the roost (the branch where all of you spent the
night).
First Autumn
By fall, you started feeling restless and yearned to fly and fly and fly.
Other robins seemed to be feeling the same way. Sometimes you’d
see a big flock flying overhead and you’d fly up and join them.
You went to lots of places, and got to eat a lot of new things you’d
never tasted before. You got used to having a lot of other robins around
feeding in the same fruit trees, roosting in the same trees, and moving
about in flocks.
Spring: Establishing a First Territory
As the days started getting longer at the end of winter, you started
feeling restless again. But now the feeling became more complicated —
you suddenly needed to find a territory. But where? For the first time
in your life, you didn’t always want other male robins close to
you. But how would you send them away?
That’s
what was happening to a couple of robins Laura Erickson watched when she
was in Nebraska in March. They had separated from the big migratory and
feeding flocks and seemed to be interested in establishing a territory
for the first time. But the problem was, they picked the same place! They
were used to being with lots of robins and weren't quite sure how to make
the other male go away.
Video
Viewing Guide Watch
the video of this encounter; view it more than once. See if you can figure
out the answers to these questions:
Q1. Are either of the robins looking for food?
Q2. An American Robin is about 25 cm (10 inches) in length.
Using that as a gauge to answer this: About how far do you estimate these
robins stay from each other?
Q3. Why do you think the robins finally flew at each other?
How long did the battle last? Why do you think they stopped fighting? Why
do you think they stayed together after the battle?
(Laura Erickson watched them fly at each other twice before she started
making the video, and didn’t know how long they’d been competing
like this. After the third robin chased them off, they flew about 20 feet
away and started competing all over again.)
Q4. Where did the third robin come from? Laura Erickson
thinks that one was older than the other two. Why did she come to this conclusion?
Q5. When the third robin flew in, one robin stood its ground
for a few seconds. The second robin almost immediately flew off. Why do
you think the first robin flew away with the second robin instead of battling
the new bird?
What's
Next for These Robins?
The first year a bird tries to find a territory, it takes a while and
a lot of exploring to find an open territory and then defend it against
other young birds. But eventually — probably within a week or two
— these two robins will find their own spaces, and will learn to
defend them. By next year, they’ll be the experienced birds chasing
off a new set of “new kids on the block.”
Try
This! Journaling Question
- Have you
ever played basketball one-on-one? When you start playing with someone
new, you have to figure out your opponent's strengths and weaknesses.
When your opponent moves forward with the ball, you keep up and try
to stop him or her. Sometimes one person will dribble and try to set
up a play while the other player tries to stop that play.
How is a game of basketball similar to what these robins were doing?
How is it different? What is at stake in a territorial battle between
robins? What is at stake in a basketball game?
- Name three
other species of animals that defend a territory. Choose one and list
some ways its territorial behaviors are similar to, and different from,
those of robins.
National
Science Education Standards
- Scientists
develop explanations using observations (evidence) and what they already
know about the world.
- The behavior
of individual organisms is influenced by internal cues (such as hunger)
and by external cues (such as a change in the environment).
- Plants
and animals have life cycles that include being born, developing into
adults, reproducing, and eventually dying.
- An organism's
behavior patterns are related to the nature of that organism's environment,
including the kinds and number of other organisms present, the availability
of food and resources, and the physical characteristics of the environment.
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