Tiny but Tough Finding food is one challenge. Facing the weather is another. T e rufous may battle hail, lightning, even gale-force winds on his trip. But sometimes, he can get lucky. A strong tailwind can help push him along. On a good day, he might cover as many as 37 kilometers. Day by day, he makes his way south through


Canada and along the foothills of the Rocky Mountains. In the mountains, he may fl y as high as 3,840 meters. But he mostly fl ies low so he can spot places to stop and rest.


Food Fight One evening, the rufous hummingbird reaches a mountain meadow. He stopped at this same place last year. In the morning, as the sun warms the meadow grasses, he looks around. He’s not alone. Many diff erent birds, including other hummingbirds, fl it around. Calliope, Anna’s, and broad-tail hummingbirds hover around the precious fl owers. T e hummingbirds in this mountain


meadow are just some of the 330-plus species of hummers. All of them live in the Western hemisphere. Most of them live in Central and South America. T ere’s lots of competition for nectar in the


meadow. T e hungry rufous will have to act fast and act tough if he wants to eat. He scouts out a patch of his favorite fl owers. He dives in, feeding greedily, fl ower aſt er fl ower. Between sips, he perches, standing guard over his fl ower patch. When a broad-tail hummer approaches, the rufous goes into attack mode. He dive- bombs the intruder, defending his territory. T e feisty little rufous chases off all competitors.


Deep Sleep Aſt er a long day, the rufous needs some rest. Sometimes a hummingbird needs more than just a simple nap, though. If the night is cool, these little birds can go into a state called torpor. It’s a kind of short-term hibernation. During torpor, the rufous hummingbird’s


breathing rate is cut in half. His rapid heartbeat drops by 50 beats a minute. His metabolism slows by as much as fi ve percent of its normal rate. T is helps him preserve his body heat and save energy. In the morning, he wakes slowly. His heart


and breathing rates increase. He vibrates his wing muscles to warm up. He is rested and ready to begin his day-long search for food. T e rufous spends about a week in this


meadow. He eats as much as he can and rests. T en he fl ies on and on, heading south.


Touching Down At last, the rufous hummingbird reaches central Mexico. His migration has taken more than three months. He settles in an oak forest on a mountain slope, and his fi rst priority is to eat. He and the other male hummingbirds have


arrived at their winter grounds about three weeks before the females. T e males will spend this time staking out their territories. Here, the rufous will make his home for the season. T en he will search for a mate. T is will not be his permanent home,


though. Come spring, he and the other hummingbirds will travel again. T ey will each head north and fl y the way they came until they reach Alaska again. T ere, they will live during the summer, and the cycle continues.


Wordwise adaptation: a behavior or body part that helps an


animal survive


migration: to move regularly from one region or climate to another torpor: a deep sleep


8


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24