Robins and Their Mates
days grow longer in spring, robins suddenly develop an urge to move northward,
to separate from other robins and live on a territory, and to build a
nest and raise babies. But they can’t separate from every single
robin! In order to raise babies, they need to choose
one particular robin who they’ll allow on their territory to be
How does a robin choose this one special bird? How long do mated robins
stay together? Does the bond last for life?
Home, Sweet Home! Claiming a Territory
The first thing robins do in spring is to arrive on and claim a territory.
We can easily observe males doing this; they sing as well as chase other
males off the territory. Females are much quieter, but equally determined
to defend their territory against other females.
Females arrive on territory a few days to a week behind the males. Most
of the males’ territorial battles are over by then. Females probably
select a territory by how good the habitat looks, but often notice the
territory in the first place because of the male’s singing. When
a female enters a male’s territory, he doesn’t chase her away.
He does notice her, often singing even more. If she likes what
she sees and hears, she starts looking around for a good place to build
a nest. It turns out that even though robins are devoted mates, they first
fell in love—not with each other but with the territory!
The mates stay closely bonded during the summer season.
Each is responsible for certain jobs as they raise their babies. The female
builds the nest, though the male often brings her some of the materials.
He continues to sing as she lays the eggs and incubates them. When the
babies hatch, both the parents get busy feeding them. When the babies
fledge (leave the nest), both parents continue to follow
them and feed them for a few days. But then the female gets busy building
a new nest and laying new eggs. While she incubates the new brood, the
male continues taking care of the older babies. He leads them to a stand
of trees in the evening where they will roost with other robins. By the
time the new eggs hatch, the older babies are ready to be on their own,
and the male is able to help feed the new babies.
Through the Seasons
nest twice and sometimes even three times in a single season. By sharing
responsibilities, they can raise as many as twelve healthy babies every
year. But as the last brood fledges and becomes independent, the male
and female feel less attached to the territory. They grow restless to
travel and associate with other robins. There’s little evidence
that a mated pair remains together during winter. But when spring comes
again, if he’s survived, the male returns to his familiar old territory.
Spring: Together Again?
around his old territory, a male knows all the best hiding and feeding
places, and has a lot of experience spotting intruders and chasing them
away. That means he has a better chance than any other robin of defending
the exact same territory year after year. A few days later, if she survived
the winter, the female returns to where she raised babies the year before.
Like the male, her experience gives her a better chance than other females
to keep the territory.
Do the two birds recognize each other? No one knows for sure. But there
are many cases of robins mating with the same bird for several years in
a row, and their experience probably helps increase the likelihood of
success in raising their babies.
If the male does not return, another male will discover and take over
his territory. When the female returns to the territory, she will accept
the new male as her mate. If the female doesn’t return, the male
will accept any other new female attracted to the territory.
A Case Study in Robin Mates
"Robin Hood" is a male robin who established a territory and
has returned to it each year for four springs. "Maid Marion"
appeared on the territory during Robin Hood’s third year, and also
returned the following year. Read more here:
North's robin expert Laura Erickson calculates that next year there is
25% chance that BOTH Robin Hood and Maid Marion will return,
25% chance that NEITHER Robin Hood or Maid Marion will return, and
50% chance that ONE of them will return.
What If One Robin Dies?
A sad thing happened in Laura Erickson’s yard last summer. She heard
loud squawking and ran out to see her favorite male robin being eaten
by a Cooper’s Hawk, and the poor robin was still alive! The robin’s
mate kept flying in the hawk’s face, but the hawk hunched over and
kept eating. Two crows came down to investigate. They stood quietly several
feet away, waiting just in case the female succeeded in driving off the
hawk, so they could finish off the male. Even after the male died, the
female kept squawking and flying at the hawk until it finally flew away.
Laura was very sad, because the dead male robin had come to her yard for
several years, and always sang at the top of her spruce tree. She was
shocked the next morning to find another male robin on the territory;
the female quickly accepted him as her new mate. He helped her raise the
babies she already had, and then mated with her and helped her raise those
This! Journaling Questions
- Did you
ever see an advertisement for something you’d never known about,
and then decided to buy it when you looked at it in a store? Why do
you think the robin’s song is sometimes called an “advertisement”
for a female?
- One scientific
study showed that about 75% of all fledgling robins die before November
their first year. Of those that survive that long, about half die before
the next November. About half of all 2-year-old robins die each year,
and about half of all robins of every other age die each year, too.
If this is true, and if 200 robins were fledged in a town one year,
how many of the fledglings would be alive in November? How many would
be alive the following November? How many would be alive the following
November? How many years would it be before all these fledglings had
- Does it
make sense that half of all 6-year-old robins die every year, and half
of all 1-year-old robins die every year? Birds that are old have the
same chance of surviving from one year to the next as birds that are
young. Can you explain why? Based on that data, how much of a chance
does a robin have that his or her mate will return to their territory
the next spring?