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Hummingbird Migration Update: April 26, 2001

Today's Report Includes:

Steady Progress

Ruby-throated Hummingbird

Courtesy of Lanny Chambers, Hummingbirds.net

Ruby-throated Hummingbirds made steady progress this week, moving into Wisconsin and Iowa, and farther north in Michigan and the New England states. They aren't normally expected in Wisconsin until the first of May, though the earliest on record was seen one year on April 15. Carol Mather reported on April 24, 2001, from Mt. Gretna, PA, "We were very excited to see our first male Ruby Throated Hummingbird this season. We've had the food out for about 2 weeks just in case. It's the most wonderful thing that happens the whole year...when the Hummingbirds return!"
Considering how late spring has arrived in many places this year, why do you think hummingbird migration is pretty much on course?

Rufous Hummingbird

Courtesy of Mike Patterson
Neawanna Wetland Ecological Observatory

There have been more Rufous Hummingbird sightings in British Columbia and Alaska this past week, still fairly close to the coast, but not a lot of reports. Journey North received one Rufous sighting inland at Reno, Nevada. When do you think we'll start seeing reports of northern birds moving further inland?

Egg-to-Fledgling Countdown
The baby hummingbirds in Dorothy's maple tree are 12 days old as we peek into the nest on this week's photo safari. They're seeing more of their world, and getting active. Check out what's going on by viewing this week's photo gallery. Clicking on each image gives you more facts and details to understand what you're seeing and to help you answer the Countdown Challenge Questions. Here are this week's photos and questions:

Day 12A: Green But Not With Envy

Day 12B: No Squabbling Here

Day 13A: Tight Fit

Day 13B: We're Changing

Day 13C: Might As Well Sleep

Day 14: Changing Positions

   

  Photos courtesy of Dorothy Edgington.

 

 Day 15: Dream A Little Dream

 

Challenge Question #21:
"Why don't baby hummingbirds bicker as some other baby birds do?"

Challenge Question #22:
"How do we know that one of these babies has been moving around?"

(To respond to these questions, please follow the instructions below.)

Try This for Size!
The babies in these photos are growing fast; yet, when full grown they'll only weigh about 3.3 grams. That's about one ninth or one tenth of an ounce. It doesn't take too many raindrops to outweigh a hummer! Using an eye-dropper and a balance, find out how many drops of water balance three grams.

Four Million Wing Beats Without a Break
Despite their tiny size, Ruby-throated Hummingbirds are sturdy and powerful. Many of these tiny birds migrate all the way over the Gulf of Mexico in spring, making a minimum of four million wing beats without a break! A sudden storm can dash some of these tiny birds into the Gulf, but the vast majority of them make it to shore, even in a driving rain. But obviously, hummers must prefer to migrate when weather conditions are favorable. They have no meteorologists to forecast the weather, but their own tiny bodies can act as barometers. When air pressure falls, many birds feed more heavily, as if anticipating a coming storm.

Teacher Tip: The Built-in Barometer
A very sensitive inborn barometer is a handy adaptation for all birds, even non-migrants. But recognizing air pressure helps migrants because birds often migrate along frontal systems, and changing air pressure is one of the first signs that a front is coming. High pressure systems often have clear skies, and flying on high pressure days may even help "buoy" birds up a bit. Interested? Investigate more with our lesson:

Radar and Migrations
Unlike birds, we humans can watch or read weather reports on TV, the Internet, or newspapers when we want to travel or make plans. Interestingly, the Doppler radar used to forecast weather can also give ornithologists, and us, information about bird migration. Here's how Doppler Radar Works: A Doppler radar facility shoots microwaves into the atmosphere. When a microwave hits an obstruction, most of it scatters, and some bounces back to the radar facility, where it gives three kinds of information: what size particles are up there, how far away they are, and how fast they are traveling toward or away from the radar source.

Meteorologists use this information to look at weather systems and see how fast they are traveling. Ornithologists use the information to track bird migration. To learn how:

Click on the Clemson University RADAR page to find a link to Doppler radar maps for your area if you're in the continental U.S.

Meet Andy!
A few weeks ago, this report came into our data bank: "I just saw my first Hummingbird! Last year was April 7, this year April 6." The sender was ninth-grader Andrew Sims. We learned that Andy is an enthusiastic hummingbird watcher and we asked him to tell you more:

Hey, My name is Andrew Sims. I live in Simpsonville, SC. I am 15 years old and this is my third year feeding hummingbirds. I currently have 10 hummingbird feeders plus a fake flower feeder that you fill with sugar water and stick in the ground, and a hummingbird wand to hand-feed the hummers. I have had some great encounters with the hummers. My very first year feeding them, one went up under our patio umbrella and couldn't find its way out. I tried to get it, but my hands were shaking so my dad got it and I petted it before he let it go. This past year I put my fingers over some of the perches on one of the hummingbird feeders and a hummer came and sat on my finger and drank. It was really exciting.

Attracting hummingbirds is easy. All you have to do is buy a hummingbird feeder at a store. Boil water and mix one part sugar to four parts water. Make sure you change and clean your hummingbird feeder every 3-5 days when the temperature is over 70 degrees.

Here are two challenge questions that Andy sent you:

Challenge Question #23:
"How do hummingbirds find the hummingbird feeders?"

Challenge Question #24:
"What are some of a hummingbird's predators?"

(To respond to these questions, please follow the instructions below.)

Thanks, Andy, for your observations and your good questions! We're waiting to hear the answers from all you other hummingbird watchers. And remember Andy's reminder to prepare your feeders. If your hummers haven't already arrived, they're on the way and need that nectar!

NOTE: Before mixing the water and sugar, it is important to first boil the water for several minutes to help keep the feeder sanitary and clean. Let the sugar water mixture cool before filling the feeder. Store unused sugar water in the refrigerator. Remember! Any sugar water will spoil rapidly in warm weather or direct sunlight, so cleaning feeders frequently is very important to the health of the hummingbirds.
Learn MORE tips for welcoming and providing for your hummers, and put yourself on our map:

Feisty Little Dazzlers
Photo Courtesy of Larry Gates, hummers@vtv.net
Very little is known about courtship in ruby-throated hummingbirds. Maybe you can help solve this mystery through your own observations!

The whole point of courtship, however, is clear: to mate and have young.
Do hummers keep the same mate season after season? No. They don't even stay together to raise the babies. The female does ALL the work herself, and a male hummer will mate with any females he can attract to his territory.
Establishing territory is very serious business. Male hummingbirds usually arrive on the breeding grounds way ahead of the females and start to establish their territories. They look for areas with lots of nectar-rich flowers and with perches from which they can survey their domain. The size of a hummer's territory varies with the number of flowering plants and the amount of nectar those plants will provide, but an average territory is about 1/4 of an acre (about 1/4 the size of a football field). If the flowers in a male's territory finish blooming, he knows what to do: he simply changes his territory to another spot with more flowers.

Any hummingbird that enters the territory, whether male or female, gets chased. Hummers are feisty and pugnacious! If the bird doesn't leave, the territory holder may respond with several types of aerial displays, such as diving, spreading his tail, or other displays. Not only the males, but females defend territories around the nest, and sometimes around food sources too. Watch for these behaviors when your hummers are around!

Hummers Keep Flight Gear in Tip-Top Shape
Photo courtesy of Harlan and Altus Aschen.
They fly forward and backward at lightning speed. They hover in one place long enough to drink a nectar meal, or zigzag through the air catching tiny insects in their mouths. These tiny flying jewels are winged wonders in the air. But hummingbirds are just as remarkable when they stop to care for their most important flight gear: their feathers. Like flight crews that get airplanes ready to fly, hummers work to keep their flight gear (in their case, feathers) in top condition. Preening is what it takes, and all birds do it.

Birds preen to remove parasites and to clean and oil their feathers. Preening also helps put in place the barbs that "zipper" together to restore each feather's smooth surface. Hummingbirds have fewer feathers than other birds. But even a tiny Ruby-throated Hummingbird has about 940 feathers to keep in order, so it stops flying several times a day to preen. That brings us to:

Challenge Question #25:
"How does preening help a hummingbird fly?"

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

Try This! Pre-flight Preening Routine
Attach a small twig (narrower than a pencil) somewhere near your hummingbird feeder to increase your chances of seeing hummers preen. Make sure the perch is sturdy. You want to give your hummers a safe place to perch as they preen, where they can survey their feeding territory. A misting hose or a mister near a hummer feeder will help too, as hummers enjoy zipping through the spraying water. Hummers are also attracted to dripping water. Create some drips by hanging a tin can with a couple of tiny holes punched into the bottom several feet over a bird bath. Fill the can with water. The water dripping from the holes will often attract hummingbirds as well as other birds. Once they're wet, hummers HAVE to preen. Watch to see the steps a hummer follows as it preens:

  • When preening, a hummer first ruffles its feathers, fluffing out.
  • Then it uses its long bill to nibble along each feather. The nibbling removes oil, dirt, and parasites.
  • As it nibbles, it takes tiny droplets of fresh oil from a gland at the base of its tail (the oil gland looks like a tiny pimple) and works the oil into its feathers.
  • Next it thoroughly cleans its flight feathers, running each feather of its wing through its bill. This action zips closed any places where the feather barbs have separated.
  • Then it uses its tiny claws to scratch hard-to reach places, such as the back of its head and neck. It also cleans its bill from base to tip, using its claws and nearby branches to wipe it clean. (Remember: nectar is sticky, so hummers need to clean up!)
  • When done, the hummer ruffles its feathers once more so they all fall neatly into place.
  • The hummer stretches each wing, lowers its head, fans its tail, and takes off!


A Partnership That Works: Response to Challenge Question #16
The tiny holes drilled by this Yellow-bellied Sapsucker are an important source of sweet fluid for Ruby-throated Hummingbirds in early spring.
Courtesy of Ann Cook.
You know that a sapsucker's sap drilling is helpful to hummers, and last time we asked you this: "In what way are hummingbirds helpful partners to sapsuckers?"

In northern Wisconsin one May, ornithologist Laura Erickson spent many hours studying some sapsucker trees. One of these woodpeckers had drilled circles of holes in three different aspen branches for feeding. While the sapsucker fed or rested on one branch, Laura watched other birds--Ruby-crowned Kinglets, Cape May Warblers, Yellow-rumped Warblers and Eastern Phoebes--come to the holes in the other two branches. Most of the time, two or three birds gorged themselves at each feeding spot. But whenever a hummingbird visited, it pugnaciously chased away any birds that happened to be there--except the sapsucker. While hummingbirds eat a lot of food compared to their body weight, they don't eat much compared to warblers and phoebes. Therefore, hummingbirds may be helping sapsuckers by defending the sapsucker's hole borings from other larger, hungrier species!

Discussion of Challenge Questions #17 Through #20
Because we're asking so many challenge questions in connection with the Countdown photos, we are placing the responses to those questions on their very own Web page. Then you can refer to them whenever you are ready to discuss the answers. Here's where you'll find the discussion of Countdown Challenge Questions #17 through #20 from our April 12 report:

Year-End Evaluation: Please Share Your Thoughts!
Please take a few minutes to share your suggestions and comments in our Year-End Evaluation Form below. The information you provide at the end of each year is the single most important tool used to guide our planning.

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Year End Evaluation
Please share your thoughts

How to Respond to Today's Challenge Questions:
Please answer ONLY ONE question in EACH e-mail message.

1. Address an e-mail message to: jn-challenge-humm@learner.org
2. In the Subject Line of your message write: Challenge Question #21 (or #22 or #23 or #24 or #25).
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 May 10, 2001.

Copyright 2001 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form

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