Hummingbird Migration Update: March 4, 1999

Today's Report Includes:

Hummingbirds Right on Schedule!
Ruby-throated hummingbirds haven't started to migrate, and only a few Rufous Hummingbirds seem to be moving so far. All reports of them this year have been very close to the Gulf Coast, the Pacific Ocean, or the Mexican Border.

Special thanks to Lanny Chambers for contributing migration data again this spring. Be sure to visit his WWW site, "Hummingbirds".

Challenge Question # 2:
"Why do you suppose all the sightings of wintering and early migrating hummers cluster along the Gulf Coast, the Mexican Border, or near the Pacific Ocean?"

This is the month when hummingbirds start to migrate, and they return to most of North America in April and May. So there's still plenty of time to get your hummingbird feeders cleaned out and your gardens planned out to make migration and nesting easier for hummers. For ideas on how to create habitat for hummers, visit Journey North's Unpave the Way for Hummingbirds.

Hummers burn up a LOT of energy migrating! To figure out just how much work they must do, try solving this week's

Challenge Question # 3
"Let's say a Ruby-throated Hummingbird fattens up in the Yucatan Peninsula of Mexico, and then lights out over the Gulf of Mexico from Campeche. It flies in a straight line to Galveston, Texas. It can't rest or feed while over the Gulf, and can't soar or glide, so it must beat its wings the whole way. How many times must it flap its wings during that over-water journey?"

To solve this, you will need the following facts:

• The distance between Campeche, Yucatan, Mexico and Galveston, Texas, USA. Use a map to figure this out.
• How many miles per hour the hummingbird is flying. The average speed is 29 mph, but to make the math easier, let's assume this one is going a little faster than normal--it's flying 30 mph.
• From these two facts you can figure out how many hours the hummingbird is flying.
• One scientist used high speed motion pictures to measure the speed of a Ruby-throated Hummingbird's wings in forward flight--it's 75 beats per second.

There! Now calculate!!

To respond to this week's Challenge Question, see below.

Discussion of Challenge Question # 1
We asked, "The tropics have so much biodiversity compared to the temperate zone. Why do you suppose hummingbirds bother to migrate back to the north every year?"

The Ferrisburgh Central School Third Grade came up with a great explanation: "We think that the hummingbirds come back north to lay their eggs. We think that there might be fewer animals that would want to eat their eggs in this area. There are more dangers in the tropics."

In much of North America, there are animals - mostly snakes, squirrels, jays, and crows - that eat bird eggs, but there aren't nearly as many egg-eaters as there are in the tropics!

Ms. McNamara's fourth grade class at St. Wenceslaus School in New Prague, MN, mentioned another important reason: "We think hummingbirds return because if they all stay down in Mexico they will run out of flowers and plants to take nectar from for food. In the spring and summertime in Minnesota there are lots of insects around the flowers to eat, too." They might not run completely out of food in the tropics, but they sure do have a LOT of different kinds of tropical hummingbirds to compete with, for both food and nesting sites. They'd spend most of their time chasing other hummers away instead of eating down there!

How to Respond to Today's Challenge Questions