About us: We own the Wild Birds Unlimited nature shop in East Lansing, Michigan,
a store that provides a wide variety of supplies to help you enjoy the birdwatching hobby.

This blog was created to answer frequently asked questions & to share nature stories and photographs.
To contribute, email me at bloubird@gmail.com.

Saturday, May 30, 2015

Birds have evolved alarm signals to warn of danger

Dr. Erick Greene, a professor of biology at the University of Montana, has shown that animals such as birds, mammals and even fish recognize the alarm signals of other species. Some can even eavesdrop on one another across classes. Red-breasted nuthatches listen to chickadees. Dozens of birds listen to tufted titmice, who act like the forest’s crossing guards. Squirrels and chipmunks eavesdrop on birds, sometimes adding their own thoughts.

Dr. Greene says he wants to better understand the nuances of these bird alarms. His hunch is that birds are saying much more than we ever suspected, and that species have evolved to decode and understand the signals. Dr. Greene turned to chickadees, which are highly attuned to threats.

A 2005 study published in the journal Science demonstrated how black-capped chickadees embed information about the size of predators into these calls. When faced with a high-threat raptor perched nearby, the birds not only call more frequently, they also attach more dee’s to their call.

Studying the phenomenon, he documented a “distant early-warning system” among the birds in which the alarm calls were picked up by other birds and passed through the forest at more than 100 miles per hour. While admittedly the study is fascinating, what benefit does this information provide?

Birds must make a trade-off with their time between eating and being vigilant. Alarm calls help the group share that responsibility. But when birds cannot hear predators or alarms well, each must spend more time listening and less time feeding. Noise alone (traffic and other human disturbances), has harmful effects on many of the birds.

Most migratory birds worldwide are in decline today, and noise pollution hampers their ability to hear information such as warnings and forces them to change their behavior. This work could have important implications for conservation.

Original Article: When Birds Squawk, Other Species Seem to Listen

Related Articles:
- New blue-eyed owl discovered by MSU researcher http://goo.gl/4FdZYR
- New MSU Study: Biofuel grasslands better for birds than ethanol staple corn http://goo.gl/D2yODK
- Free Downloads of Bird Sounds from Around the World via MSU http://goo.gl/ZKEKmk
- Black Squirrels’ history begins at MSU http://goo.gl/Ryxnqx

No comments: