Scientists studied green hermit hummingbirds in mountain forests of Central and South America. Males gather at display sites and fight over perches to secure mates. Before an attack, males raise their long, needle-thin bill and drive it into an opponent.
Researchers at the UW Burke Museum used photogrammetry (making 3D models from photos) and CT scans to compare male and female bills. They found male bills are straighter and sharper. Tests on the 3D models showed the straighter male bill deformed less and worked better in simulated stabbing tests. The authors say fighting helped shape the different bill forms in males and females.
Difficult words
- hummingbird — A small bird that can fly quickly and hover.
- fight — To use force against someone or something.
- food — What people or animals eat.
- mate — A partner for reproduction.mates, partners
- nectar — A sweet liquid produced by flowers.
- curve — To bend or change direction.curved
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- Why do you think fighting is common among male hummingbirds?
- How might the environment influence the shape of a bird's bill?
- What are other reasons animals might compete for mates?
Related articles
Why Rechargeable Batteries Lose Performance
Researchers found that repeated charging and discharging makes batteries expand and contract, causing tiny shape changes and stress. This “chemomechanical degradation” and spreading strain reduce performance and shorten battery life, and imaging revealed how it happens.
