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Hummingbird Migration Update: April 22, 2004

Today's Report Includes:

Rufous Hummingbirds Moving Inland--and Hatching Babies!

Rufous Hummingbird

Courtesy of Mike Patterson,
Neawanna Wetland Ecological Observatory

Rufous Hummingbird
Migration Map

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 Patterson.

Rubythroats Rushing North

Ruby-throated Hummingbird

Courtesy of Lanny Chambers,

Ruby-throated Hummingbird
Migration Map

Ruby-throated 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.”

Lanny's 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?

A 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 tree.

It start 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.)

Digging Into Data: Discussion of Challenge Question #7
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 in 2004?”

Several 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 dates?

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!

A 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:

2000 - 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:

Then try it yourself and send us your answers:

Challenge Question #9:
“Based on data given, what’s the mean arrival date for (1) Donald Rose McGhee’s hummingbirds, and (2) Betty’s hummingbirds?”

(To respond to this question, please follow the instructions below.)

Same 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.)

How to Respond to Today's Challenge Question:

IMPORTANT: Answer only ONE question in each e-mail message.

1. Address an e-mail message to:
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 above.

The Next Hummingbird Migration Update Will Be Posted on April 29* (Migration Data Only).

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