Hummingbirds migrating earlier
CHARLESTON, S.C. — Ruby-throated hummingbirds are migrating to North America weeks earlier than in decades past, and research indicates that higher temperatures in their winter habitat may be the reason.
Researchers say the early arrival could mean less food at nesting time for the tiny birds that feed on insect pests, help pollinate flowers and are popular with birdwatchers.
“Hummingbirds are charismatic, and they do things that fascinate us,” said Ron Johnson, a scientist at Clemson University and one of the study's authors. “They fly backward, and they hover, and they will come to feeders at homes so people can easily see them.”
Johnson and colleagues last month published an article on the migration of the hummingbirds in The Auk, the Journal of the American Ornithologists Union.
The birds, which weigh little more than a nickel, fly hundreds of miles over the Gulf of Mexico from their wintering grounds in Central America to arrive in North America. The research compared data on their first arrival times from 1890 to 1969 with arrival times during the past 15 years or so.
The comparison found that the birds are arriving in North America 12 to 18 days earlier than in the past.
The historical data on hummingbirds is based on government surveys from 3,000 naturalists who recorded the first spring arrival time of bird species over the decades.
About 6 million such records exist and are being scanned into computer databases by the North American Bird Phenology Program.
The research compared the historical documents with about 30,000 recent records on hummingbird arrivals. Scientists say the earlier arrival times could be problematic for hummingbirds, of which there are an estimated 7 million.
“With any bird that migrates over long distances, it's good to show up at the nesting grounds at a good time when you can set up a territory and build your nest and when the young come along there will be a lot of food available,” Johnson said.
“You want to be there ideally right when the food becomes available at its peak so the young ones will have enough food.”
Ecological systems work differently, Johnson said, and the hummingbirds' early arrival doesn't necessarily mean that the flowers and insects of their diet are available earlier.
Show commenting policy
TribLive commenting policy
You are solely responsible for your comments and by using TribLive.com you agree to our Terms of Service.
We moderate comments. Our goal is to provide substantive commentary for a general readership. By screening submissions, we provide a space where readers can share intelligent and informed commentary that enhances the quality of our news and information.
While most comments will be posted if they are on-topic and not abusive, moderating decisions are subjective. We will make them as carefully and consistently as we can. Because of the volume of reader comments, we cannot review individual moderation decisions with readers.
We value thoughtful comments representing a range of views that make their point quickly and politely. We make an effort to protect discussions from repeated comments either by the same reader or different readers.
We follow the same standards for taste as the daily newspaper. A few things we won't tolerate: personal attacks, obscenity, vulgarity, profanity (including expletives and letters followed by dashes), commercial promotion, impersonations, incoherence, proselytizing and SHOUTING. Don't include URLs to Web sites.
We do not edit comments. They are either approved or deleted. We reserve the right to edit a comment that is quoted or excerpted in an article. In this case, we may fix spelling and punctuation.
We welcome strong opinions and criticism of our work, but we don't want comments to become bogged down with discussions of our policies and we will moderate accordingly.
We appreciate it when readers and people quoted in articles or blog posts point out errors of fact or emphasis and will investigate all assertions. But these suggestions should be sent via e-mail. To avoid distracting other readers, we won't publish comments that suggest a correction. Instead, corrections will be made in a blog post or in an article.
- New Orleans slow to heal 10 years after Hurricane Katrina
- Deputy fatally shot from behind at Houston gas station
- Prosecutors won’t retry North Carolina police officer in black man’s death
- Clinton: Women ‘expect’ extremism from terrorists, not GOP candidates
- ‘Facts are bad’ for pier-shooting defendant, legal experts say
- Obama opens climate change tour
- U.S. Embassy to Japan used private emails, watchdog finds
- Suspect in 1996 Khobar Towers bombing arrested
- Eastern Pa. pastor in insider-trading scheme granted bail
- Thousands in New Orleans became targets of unscrupulous contractors
- Court lifts injunction against NSA call records program