Hummingbird Migration Update: February 15, 2001 Today's Report Includes: In Search of Hummingbirds Home on the Range: Challenge Question #1 Hungry Hummers Curious and Clever: Challenge Question #2 Perils in Paradise Smart Moves Did You Know? In Search of Hummingbirds Laura Erickson, birdwatcher in Costa Rica. The tiniest birds on the planet are on their wintering grounds right this minute, enjoying sunny skies, toasty temps, and plenty of food. They don't stick around in places where ice and snow are the normal scene in winter, nor where folks haven't seen the sun for months. That's one reason why ornithologist and Journey North writer Laura Erickson always dreamed of joining hummingbirds on their wintering grounds. This year Laura's dream came true. She spent January 2001 in Costa Rica, searching for hummingbirds and orioles. Laura saw over a thousand hummingbirds of 34 different species, including one female Ruby-throated Hummingbird. Just ONE? Laura explains, "Most ruby-throats winter in Mexico, Belize, Honduras, Guatemala, El Salvador, and Nicaragua. Smaller numbers get down into Costa Rica, and even Panama, but Costa Rica is simply not in the main part of their winter range." Laura shares some surprises and remarkable observations in this report! Home on the Range Coppery-headed Emerald Hummingbird "Costa Rica seemed perfect for the hummers that were there--Green Thorntails, Snowcaps, Violet-crowned Woodnymphs, Violet Sabrewings, Purple-crowned Fairies, Magenta-throated Woodstars, and others. Some hummingbirds, like our own Ruby-throated Hummingbird, have BIG ranges. During breeding season the Ruby-throated Hummingbird can be found throughout central and eastern Canada as far north as Hudson Bay, and throughout the eastern US. And during winter, Ruby-throats can be found from southern Mexico through all the other Central American countries and into northern South America. But this little Coppery-headed Emerald has a very tiny range. The only place on the planet where it has ever been recorded has been in Costa Rica. It has never been known to wander even to neighboring Panama or Nicaragua!" This makes us wonder: Challenge Question #1 "Why do some birds have a big range while similar birds have a very small range?" (To answer this question, please follow the instructions below.) Hungry Hummers Laura spent one morning at a Costa Rican hummingbird feeding station. Hundreds of hummers zipped in and out, sounding so lively that Laura decided to record them. She dangled a microphone from one branch, balanced her minidisk recorder on another branch, and snaked a cord between them. While she was working, the hummers kept zipping in and out as if she weren't even there. "Hummers at this place are used to birdwatchers!" Have a listen! Laura shares a bit of her recording with you: Listen to the Humming at the Feeder Laura tells more: "This hummingbird station has four big feeders, and each one must be filled at least once a day because so many of these tiny, hungry birds are there from sunrise till sunset. The hummers on the right are both White-necked Jacobins, though the female looks a lot different. The hummer on the left is a female Violet-crowned Woodnymph. Scientists still have a lot to learn about this species; Violet-crowned Woodnymphs seem to pretty much disappear from September to December, but the nature of their migration is not understood. They live from southern Mexico down to Ecuador, Bolivia, and Brazil, especially near the Amazon River." Curious and Clever Violet-crowned Woodnymph (male) After Laura finished recording, many of the hummers suddenly disappeared. One male and one female Violet-crowned Woodnymph flew in and closely examined the microphone. "This male Violet-crowned Woodnymph was very curious. He and a female hovered all along my recording equipment, inspecting every millimeter of the microphone. They made high-pitched little sounds to each other as they hover-flew, side by side, along every inch of the four-foot cord. When they reached the minidisk player, they closely examined every nook and cranny, especially the red "record" button! Why do you think they did this?" Challenge Question #2 "Why would a pair of tropical hummingbirds take time from feeding to closely examine recording equipment?" (To respond to this question, please follow the instructions below.) Perils in Paradise Laura points out, "All these hummers grew up in the tropics. They were familiar with tropical dangers that Ruby-throated Hummingbirds would certainly not have learned about growing up in North America! If a baby hummer survives its first perilous migration (remember--most of them fly over the Gulf of Mexico during hurricane season!), it still has to figure out all the brand-new dangers that it never saw before in its life. For example, many snakes kill birds in the tropics. In the northeastern states and northeastern Canada, where many Ruby-throated Hummingbirds grow up, it's very hard to find a snake. Garter snakes and red-bellied snakes live in the north woods, but both spend their lives on the ground, eating mostly insects and other invertebrates. Hummingbirds don't have to worry about them. In the places in the eastern U.S. and Canada where there are tree snakes, hummers quickly learn to recognize them and keep away! Woodnymphs love heliconia flowers like these. "In the tropics, some snakes lurk in flowers that hummers feed from. If an unsuspecting hummer ventures too close, it's mealtime for the snake! Woodnymphs often feed on heliconia flowers (see photo), and some snakes hide on the blossoms and strike out to grab hummers. Other snakes crawl along tree branches at night trying to sense warm-blooded bodies while hummingbirds are fast asleep. Forest falcons live in the tropics year-round, and Sharp-shinned Hawks spend their winters there, right with the Ruby-throated Hummingbirds. There are many more spider species, including some huge ones, and many insects large enough to take a 3.5-gram hummingbird. Predation is a far bigger problem to a small bird in the tropics than it is in the north! Smart Moves "Fortunately, despite their tiny size, hummingbirds are capable of learning new things. They quickly figure out the dangers. And because they concentrate in Mexico in winter, Ruby-throated Hummingbirds don't have to compete with as many species as they would if most of them went to Costa Rica. (There are 43 species of hummingbirds in Mexico, but 51 in much tinier Costa Rica!) Mexico has a lot more bird predators than the eastern US or Canada, but at least in Mexico, hummers are usually safe from cold temperatures." Did You Know? If hummingbirds were as big as ravens, it probably wouldn't be safe to go for a walk in the woods! As you wait for the hummers to return this spring, learn more about these tiny winged wonders. How fast do they fly? How long do they live? How much do they eat? You'll be amazed! Fun Facts about Hummingbirds! 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 #1 (or #2) 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 March 8, 2001. Copyright 2001 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form