Hummingbird Migration Update: April 22, 2003


Today's Report Includes:

• Rufous Hummingbirds Getting in Gear! Migration Maps and Data
• Feeling Broody? Challenge Question #13
• Ruby-throated Hummingbirds Cross Canadian Border
• Learn More about Hummingbirds: Challenge Question #14
• Ups and Downs: Discussion of Challenge Question #11
• Hummingbird Food Chains: Challenge Question #12

Rufous Hummingbird photo copyright by Jerry Blinn

Rufous Hummingbirds Getting in Gear!
Mike Patterson told us on April 21, 2003 that reports of Rufous Hummingbirds continued this week from southern Alaska. Reports also came from Salmon Arm, British Columbia, and Kooskooskie, Washington. He says, "The weather is slowly coming around to something more spring-like, so things should start popping."

If YOU see a Rufous Hummingbird in the West, make sure you report it to Mike Patterson. And if you see hummers, make sure you let him know if any flowers are blooming, too!

Rufous Hummingbird Migration Data Migration Map Courtesy of Mike Patterson Neawanna Wetland Ecological Observatory

A bander is holding this female robin on her back in his hand, and blowing on the tummy feathers to show the brood patch. When no one is blowing on them, the outer feathers keep the brood patch hidden. She can control her skin muscles to open the feathers, so she can put the brood patch directly on her eggs for incubating. Photo by Bill Hilton, Jr.

Feeling Broody?
Mike inspects the hummingbirds he bands, and notes that "Two of the female Rufous Hummingbirds captured on Saturday, April 19, were sporting not quite fully developed brood patches."

What's a brood patch? It's a hot patch of bare skin, with a rich blood supply, that develops on the belly of breeding females. Banders see this when they blow on the tummy feathers. Females develop it to efficiently transfer heat to incubate their eggs. When female Rufous Hummingbirds have a brood patch, it's considered good evidence of local breeding.

We wanted to show you a photo of a hummingbird's brood patch, but it's very hard to even see, much less to hold a camera in position to show it on such a tiny bird. Fortunately, Bill Hilton, Jr., executive director of Hilton Pond Center for Piedmont Natural History near York, South Carolina, who also bands hummingbirds, did have a photo handy of an American Robin's brood patch. No wonder--his center has banded nearly 46,000 birds since 1982!

To learn more about brood patches, look here:

• Feeling Broody: The Tummy Solution

Then answer this

Challenge Question #13:
"Banders can use brood patches to tell female Blue Jays from male Blue Jays during the breeding season. Why isn't this a useful way to tell female Rufous Hummingbirds from males?"

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

This Ruby-throated Hummingbird is held by bander Nancy Newfield during last fall's migration through Louisiana. Do you think it might be trapped by another bander someday? Photo by Laura Erickson.

• Lanny Chambers's Hummingbird Arrival Dates

These hummingbirds must be hungry--they're not chasing each other away! Photo courtesy of Harlan and Altus Aschen.

• Journey North Hummingbird Resources

Then using what you know about hummingbirds and history, put on your thinking cap and see if you can solve this puzzle. Some grownups who knew a lot about history were saying they read somewhere that ancient Romans ate "hummingbird soup." Is this possible?

Challenge Question #14:
"Is it possible that any ancient Romans ate "hummingbird soup"? Justify your answer with at least one fact from history and one fact about hummingbirds."

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

Of course that thin air also can't block the solar heat that hits the ground from radiating out again, and it can't block the heat trapped in the ground from radiating out. So the thin atmosphere doesn't provide much of an insulating blanket, making the air at the top of a mountain much cooler than air at lower elevations.

We could think of a LOT of food chains! One that includes a hummingbird and an oriole might go like this:

• Jewelweed plant - Ruby-throated Hummingbird - Preying Mantis - Baltimore Oriole

One with a Bald Eagle might go like this:

• Jewelweed plant - Ruby-throated Hummingbird - Largemouth Bass - Bald Eagle.

One that would include at least 8 other animals and plants might look like this:

• Rose plant - aphid - Ruby-throated Hummingbird - large spider - larger spider - garter snake - milk snake - Broad-winged Hawk - Great Horned Owl.

IMPORTANT: 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 #13 (OR #14).
3. In the body of EACH message, give your answer to ONE of the questions above.

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