Oriole Migration Update: April 19, 2001
Today's Report Includes:
This Week's Migration Map and Data
Not many orioles! A few scattered reports of individual Baltimore Orioles have
arrived, but their migration has not really kicked in yet. The cold spring weather
that's been slowing down ice-out in many areas has slowed oriole migration, too.
One reported Baltimore Oriole from Battle Creek, MI on April 8, and another on April
9 at Mactier, ON, may have been overwintering birds, since a few did spend the winter
in the eastern part of the continent. But here's proof that a few orioles ARE on
"On April 6 I awoke to TWO immature male Baltimore orioles singing from the
lilac bush on my patio! Get those oranges out!" That's the advice of Rob Zimmer
of Neenah, WI. "At first I was skeptical when it came to those radar images
of "migrating birds" that have been coming onto the Internet, but I am
convinced now. I'm sure my orioles were part of the waves that showed up on radar.
Just to imagine that these huge flocks of birds are lifting into the skies each night,
right over our heads, is really overwhelming."
Are you ready to welcome the orioles? According to Dr. Aborn, our weather wizard,
it looks like they're really on the way!
Dr. Aborn's Weather Forecast for the Birds
Dr. David Aborn
In my last report I pointed out a cold front that had stalled along the Gulf coast.
This meant that migrants arriving from the tropics would encounter several days of
rain and northerly winds, which would keep them grounded. April 5th and 6th, all
the Gulf states from Texas to Florida reported a kaleidoscope of birds. Over the
weekend (April 7th and 8th), the front fell apart, the skies cleared, and the winds
shifted to the south. You should know what that means...the birds took off!
A few days ago, a strong cold front moved across the country. It was a return to
winter. While there wasn't much rain, the strong north winds forced the next group
of migrants to land. Cuckoos have been showing up, and there has been 1 Baltimore
Oriole sighting (Cole Co., Missouri)! At Lula Lake yesterday, it actually snowed
while I was doing my bird surveys! It was a good day for Worm-eating Warblers; I
saw 6, which is a new 1-day record for me. There were also a lot of Blue-headed Vireos.
It was nice to see so many birds, but I liked it better when it was warm!
This weekend, the winds will shift to the south again, and many birds will head north.
People in the Midwest and mid-Atlantic should have a good weekend of bird watching.
Orioles will be coming in, so watch for them. In the mean time, ponder this question:
Challenge Question #4:
"The females arrive later in the spring than the males. Why do you think
to this question, please follow the instructions below.)
Find the weather map and read more about migrants in David's complete letter here:
Right now, brilliant orange and black orioles are starting to flood through North
America. Of course, they're much more noticeable when they show up right on your
bird feeder or deck railing. And right now, that's the easiest place for people to
find them. To bring them in, all you need to do is set out oranges cut in halves.
Set them on platform feeders or other flat surfaces, or string them on tree branches.
Oranges are rich in sugar, which gives the orioles a boost in energy, and their juiciness
also helps orioles keep up their fluid balance without having to search out water
in unfamiliar areas while they're migrating.
This is the time of year when orioles reverse their diets from what they eat in winter--mostly
tropical fruits and nectar, along with some insects--to what they eat in summer--mostly
insects and spiders, along with some fruits. But even as they're growing more and
more interested in insects, orioles still want fruits, especially during their exhausting
The tropics are rich in insects AND fruits. What do you think are some reasons why
orioles might switch their diets in summer?
Challenge Question #5:
"List as many reasons as you can think of why orioles eat mostly fruit in
winter and mostly insects in summer."
to this question, please follow the instructions below.)
Setting Their Sights on Orange
Orioles are often enticed down to orange feeders even in cities and other habitats
that would be inappropriate for them. How do the orioles notice these orange feeders?
Photo Courtesy Chan Robbins
Orioles are attracted to the color orange. They seem to notice it better than they
notice other colors. This may be due to some peculiarity in their eyes, but is probably
simply learned. Adult male orioles are brilliant orange, so from the time they are
babies, orioles see that color a lot. It's important for male orioles to recognize
intruders on their territories, and for female orioles to find mates, so it makes
sense for them to take particular notice of bright orange. As orioles fly overhead
during migration, partly by night by partly by day, they fly over unfamiliar areas.
As soon as they see that familiar color, they check it out. So get those oranges
out there if you want orioles to notice your yard!
Keep a Journal. Keeping track of when and where you see orioles can help you learn
more about orioles in your area. It can also be important to people in the future.
Your journal notes may help others who try to follow the trends in oriole populations
and the timing of oriole migration. Experts say some species are declining by 1-2
percent a year. It may not sound like much, but over 20 years, it adds up to a whopping
decline of 20-40 percent. Your journal can include these observations:
- How many orioles?
- When do they come for food?
- What foods do they eat?
- What do you see them eat in the wild?
- Do they nest on your property?
- Do they raise young successfully?
- When did you see your first oriole of spring?
- When did you see your last oriole in fall?
Migration Fall Out
Migratory Path Across the Gulf of Mexico
As migrants from the tropics flood north, some of them take a shortcut. Look at a
map and see how much shorter it is for a bird in Central America to cut up north
from the Yucatan Peninsula of Mexico and fly over the Gulf of Mexico than it is to
take the land route all the way along the Mexican border! The problem with taking
this shortcut is that, without islands, there are no natural places for these birds
to land if they get tired or the weather gets bad. And sometimes the weather does
get bad during migration!
Of course, even without natural islands, there are some places to land on the Gulf
of Mexico. Sometimes a ship or a boat becomes a temporary resting place, to the surprise
and delight of people onboard. And there are permanent resting spots, too, in the
form of oil rigs. Researcher Bob Russell says that in late April, 1998, a storm line
brought about 3,000 birds onto one platform at one time. "There were parts of
the platform where you couldn't walk. Bay-breasted Warblers were shoulder to shoulder,"
he told Weather.com reporter Julie Galle.
Whether they take a break on an oil platform or fly straight through, birds are exhausted
when they reach the Texas and Louisiana coasts. So birdwatchers collect at places
like High Island in Texas in hopes of being there the best day of the season, when
thousands of birds fill the trees and hop on the ground. They are so tired that birdwatchers
can walk right up to them. This situation happens most often when a frontal system
with north winds collides with a warm front. Little birds take advantage of tail
winds to help them migrate, and so they set out from Mexico on a south wind. If suddenly
they hit a mass of cold air and north winds, they either must turn around or push
on against the wind. Have you ever been pushed hard by a strong wind? Imagine weighing
less than two ounces like a Baltimore Oriole and heading into a strong wind. To learn
more about the bird that fall out of the sky onto the oil platforms, check out:
Douse Those Lights at Night!
Earth at Night
Losing habitat is just one disadvantage birds suffer as a result of modern times
and growing populations. Many song birds evolved migrating at night, when predators
retire and winds die down. The human-made lights of modern times interfere with nature's
ways. This composite of satellite images shows how electrical lights illuminate the
planet at night. These artificial lights mean big trouble for migratory birds.
Click Map to Enlarge
Photo Courtesy C. Mayhew & R. Simmon (NASA/GSFC), NOAA/ NGDC, DMSP Digital Archive
Navigating primarily by the stars, night-migrating birds become disoriented by
city lights. They confuse the billions of human-made lights in tall city buildings
with starlight--especially in foggy or rainy weather, and especially after midnight,
when the birds begin to descend from their peak migration altitude. Once disoriented,
many birds collide with the buildings and fall to the sidewalks below. Others, like
moths attracted to light, flutter around the lighted windows until they are exhausted.
Birds by the hundreds and even thousands can be injured or killed in a single night
at just one building.
You'll be glad to know that the city of Toronto's Fatal
Light Awareness Program (FLAP) is helping migratory songbirds by turning down
the lights. In the U.S., Chicago's Hancock Center has doused its ornamental nighttime
lighting so save the nearly 1,500 birds that die EACH night when they crash into
the tower during migration season, mistaking the building's lighting for stars. Will
officials at New York's Empire State Building follow the example? What about officials
in charge of tall, lit-up building where YOU live? Find out what you can do to spread
news of this problem--and to make buildings like your school and home more bird-friendly.
The facts and ideas are here:
Celestial Navigation: Discussion of Challenge
Every spring, orioles and other migrants flood over the Gulf of Mexico to their breeding
grounds in North America. Most of these birds set out just as night is falling. Even
when clouds obscure most of the sky, birds can set their direction if they can see
a wedge of stars. In spring they migrate toward the North Star. Last time we asked
this question: "What advantages does night migration have over day migration?
What special dangers does night migration have?" Here you go:
- Night usually brings less wind and cooler temperatures. Without the hot sun beating
down on them, fast-flapping little birds are less likely to get overheated.
- The stars provide an excellent navigating tool.
- Bird-eating hawks are sleeping! (Owls take most of their prey on the ground,
and even bat-hunting owls hunt at lower elevations than migrants fly.)
- Night-flying birds usually can't see the ground. Sometimes they end up over a
huge lake or even the ocean, and by the time it's light are lost and have a long
way to fly to reach land again.
- Since they can't see the ground, they have no idea what kind of habitat they
are flying over. When day comes and they land, they may be in totally inappropriate
- Songbirds have poor night vision. They can see the stars fine, but in the dark
can crash into mountains and other obstructions, including darkened buildings and
dark towers. (This happens very rarely.)
- Their navigation system depends on seeing stars, and they get confused by and
attracted to some kinds of artificial lights, crashing into lighted buildings and
lighted towers. This kills millions of birds every year.
Note To Teachers: We'd Appreciate Your Thoughts!
In our May 3 update, we'll be asking for your feedback on the Journey North program.
Watch for our Year-End Evaluation Form and please plan to take the time to send your
suggestions and comments. The information you provide at the end of each year is
the single most important tool used to guide our planning.
How to Respond to Today's Challenge Questions:
IMPORTANT: Answer only ONE question in each e-mail message.
1. Address an e-mail message to: email@example.com
2. In the Subject Line of your message write: Challenge Question #4 (or # 5).
3. In the body of your message, give your answer to the question above.
The Next Oriole Migration Update Will Be Posted on May 3, 2001
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