Migration Update: April 22, 2004
Hummingbirds Moving Inland--and Hatching Babies!
Do you remember a couple of weeks back
when Ann from Saanich, BC reported watching a female Rufous building
a nest? Now she reported watching the bird feeding newly-hatched youngsters!
(Watch for exciting close-ups on hummingbird babies later in today’s
report.) Nesting may have begun for a few, but others are still migrating.
This week brought continued reports of Rufous hummingbirds moving to
the east (inland) from eastern Washington and Idaho. When do you think
we'll start seeing reports of northern birds moving further inland?
This might help:
Pull out an atlas for elevation information and then compare with this
week’s migration map. Have you noticed that Rufous hummingbirds
arrive later in the Coast Range and foothills of the Cascades than they
do in the Willamette Valley? The Coast Range and Cascades are mountainous
areas. You know that temperatures are colder at higher elevations. (For
every 250-foot increase in elevation, the temperature drops about 1
degree F.) Hummingbirds prefer warmer temperatures. Plant development
is slower at cold temperatures, too. This means the hummingbird habitat
is ready earlier in the Willamette Valley (lower elevation) than in
the Coast Range and foothills of the Cascades (higher elevations).
If you live in the West and see hummers, make sure you report them—and
any flowers blooming--Mike
Hummingbirds made steady progress again this week, moving further into
Michigan and Illinois, and then finally into Wisconsin, Minnesota and
the Upper Peninsula of Michigan. We’ve had over 160 new sightings
in the last two weeks. But look closely: Do you see a “gap”
where you’d expect the hummingbirds to be? Dr. David Aborn says,
“I have seen years where a persistent weather system brings poor
weather over an area, and the birds avoid it or go around it. That might
explain the lack of Ruby-throated Hummingbirds west of the Mississippi
River.” What can you find out about the weather and the wind patterns
in those regions last week?
Lanny Chambers, who supplies most of the data on this hummingbird migration
map, also points out an interesting thing to ponder: “That push
into Michigan is remarkable, isn't it? I think it's at least partly
an artifact of increased Internet access and awareness of my map. I
expect more early dates every year as the pool of observers grows. Remember
that the map only shows the earliest birds, the outliers on the bell
curve; most people won't see any hummers until a week or two after the
first individuals pass through.”
First Hummer Arrived!
Speaking of first individuals, we checked with Lanny, telling him that
it’s always a big deal for Journey North when his first hummingbird
arrives. He replied: “My first hummer appeared the afternoon of
April 20. You think it's a big deal there? You should see what it's
like HERE!! It won't get a dot on the map, but if it is still here tomorrow,
it might get a nice aluminum bracelet.” How does the April 20
date fit with your prediction for the answer to CQ #7? But first, what
have the arrivals been up to?
Peek in the Nest: Challenge Question #8
Last time you learned about hummingbird nest building. Already, or soon,
those will be full. Have you ever wished you could peek into a hummingbird
nest to watch the eggs hatch and the babies grow? You CAN, with Journey
North’s photo safari! Share the adventure in Dorothy’s maple
with photos before hatching. This week, let’s follow along up
through the Day 5 in the babies’ lives (the photo labled “Snuggling”).
Please click on each photo to examine in greater size and detail. This
helps you answer the questions by each photo, and perhaps raise new
questions of your own. For example, how did the female build the nest?
What would YOU look at and think about if you had to sit in a nest on
a tree branch most of the day for two weeks? If we tell you sunrise
and sunset times, can you figure out how much time a female hummer spends
incubating her eggs on June 1 in Lansing, Michigan? Why do hummingbirds
almost always lay exactly two eggs? How does the eggshell of a hummer
egg compare to the shell of a chicken egg? On what day do the babies
open their eyes? Until then, how do they know when their mother has
returned with food for them? Here we go!
Then come back and answer...
Challenge Question #8:
"What are at least two things that baby hummingbirds can do as
soon as they hatch out?"
(To respond to this question, please follow the instructions below.)
Into Data: Discussion of Challenge Question
Last time we shared 10 years of data sent by Lanny Chambers, our Ruby-throated
hummingbird expert. (Lanny hadn’t yet seen his first hummer of
2004.) We asked: “What is the range and what is the median of
Lanny Chambers’s first arrival dates for Ruby-throated hummingbirds
in St. Louis? When do you think Lanny’s first hummer will arrive
students had fun with this question! Congratulations and THANKS to the
number crunchers who took a close look at the data and sent their answers:
Range is 16-23, or 7 days; median
arrival date is April 19. Kudos to Iselin (NJ) Middle School grade 7
students Sriram, Stephanie V, Anelia, Stephon, Justin, Kyle,
and Anthony B; and Julie from Ms.Pfaff's 7th
Grade Science Class at Challenger Middle School in San Diego, CA!
Several of you were a jump ahead of this week’s CQ #9 when you
averaged the dates (found the mean) to come up with
the estimated arrival date for Lanny’s first hummer. Did the actual
arrival date of April 20 match the average of his 10 previous arrival
Did any of you use Julie's method for finding the median?
“I put all the numbers in order from greatest to least: 16 16
17 19 19 19 20 20 22 23. I crossed the numbers out from each side and
eventually ended up with 19 and 19. Since the mean of 19 and 19 is 19,
I got the date April 19th as the median.”
In addition, Julie noticed “that the years 1998, 2000, and 2002
have earlier arrival dates than those of the odd years.” Thanks,
Julie, for showing that the more we look at data, the more we see!
Now, all the rest of you have a chance to calculate the mean for next
time with our lesson using Lanny’s data. Read on!
Mean Question: Link to Lesson and CQ #9
“I'm excited! Just saw my first hummer for 2004 at 8:10 this morning.
A nice Ruby-throated male. He was on time,” wrote Donald
Rose McGhee from Louisburg Elementary in North Carolina on
April 10. “I put out the feeder about 3 weeks ago. The juice in
the feeder was going down but I had not seen any hummers until this
morning. This is the schedule for arrival for the past few years that
I have kept track:
- April 11
2001 - April 8
2002 - April 9
2003 - April 7
2004 - April 10
Can you see that, indeed, the hummer was “on time?” Here’s
another question: What’s the mean arrival date
for these hummingbirds? Learn how to calculate the mean arrival date
with our step-by-step example in this lesson:
it yourself and send us your answers:
“Based on data given, what’s the mean arrival date for
(1) Donald Rose McGhee’s hummingbirds, and (2) Betty’s
(To respond to this question, please follow the instructions
Bird? Same Route? Journaling Question
“Banding studies show that each bird tends to return every year
to the same place it hatched, even visiting the same feeders. Banding
studies suggest that individual birds may follow a set route year after
year, often arriving at the same feeder on the same day,” wrote
Lanny Chambers in a Ruby-throated hummingbird article published recently.
“We do not know if any individual bird follows the same route
in both directions, and there are some indications that they do not.”
Try This! Journaling Question:
Imagine you are a scientist. How could you study whether hummingbirds
follow the same migratory route north AND south? Which ideas would you
rule out? (Mark them with X.) Which would have the most likely success?
(Mark them with a star.)
to Respond to Today's Challenge Question:
Answer only ONE question in each e-mail message.
an e-mail message to: email@example.com
2. In the Subject Line of your message write:
Challenge Question #8 (OR #9).
3. In the body of EACH message, give your answer to ONE of the questions
Next Hummingbird Migration Update Will Be Posted on April 29* (Migration
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