Wild Ideas: Nature notes: Bird migration, bold tadpoles and more   

In checking my email inbox recently, I found lots of news about birds, including finches that talk to their eggs, and about bold tadpoles and art exhibitions celebrating the National Park Service’s centennial.

Help chart hummingbird migration

Mature male ruby-throated hummingbirds that breed here in Virginia usually depart by mid-summer, their sole reproductive job — breeding — done. Most males that show up at feeders at this point in the year are either immature ones from produced this summer or those traveling through from further north. Females stick around to raise their second broods and fuel up for the trip, and some immature males to do the latter, but both are usually gone in the northern Piedmont by early October.

Female or juvenile male ruby-throated hummingbirds, which look similar, vie for a place at the feeder.
Female or juvenile male ruby-throated hummingbirds, which look similar, vie for a place at the feeder. By Pam Owen

My feeders are a zoo right now, so to speak, with about a dozen hummers vying for places at them from dawn to dusk. While the ruby-throated are heading south, rufous hummingbirds and possible rare strays of five other hummingbird species may be heading into our area. (See more about them on the official state list at the Virginia Society of Ornithology’s website.

The organization Journey North invites citizen scientists to help track the hummers’ migration. To enter sightings, go to its website or report your observations with a mobile app that can be downloaded from there.

‘The Messenger’ explores threats to songbirds

The Smithsonian Conservation Biology Institute (SCBI) and the American Bird Conservancy (ABC) are hosting a screening of the film “The Messenger” at the Little Washington Theatre (291 Gay St., Washington, VA) Sept. 16 at 7:30. The film, produced by SongbirdSOS Productions Inc., was shot from the northern reaches of the boreal forest to the base of Mount Ararat in Turkey to the streets of New York. It “brings us face-to-face with a remarkable variety of human-made perils that have devastated thrushes, warblers, orioles, tanagers, grosbeaks and many other airborne music-makers” and “explores our deep-seated connection to birds and warns that the uncertain fate of songbirds might mirror our own,” according to SongbirdSOS’ website, which also features a trailer of the film.

After the showing, which is free, bird experts from SCBI and ABC will answer questions. For more information, contact Amy Johnson at SCBI, johnsonae@si.edu.

Bird parents school unhatched young

In skimming through my emails from “Science” magazine, a headline really drew my attention: “Zebra finch call prepares their eggs for climate change.”

Originally from Australia, zebra finches are often kept as pets and have colonized other parts of the world, including the U.S. According to the article, which is accompanied by an informative animated video, scientists noticed that a female zebra finch brooding her eggs would vocalize for no apparent reason when it was hot outside.

A new study shows that zebra finch parents can teach their young to be prepared for climate change before they hatch.
A new study shows that zebra finch parents can teach their young to be prepared for climate change before they hatch. By Peripitus via Wikimedia

In the lab, the researchers tested the broods of finches that received these special “incubation calls” from parents (or recordings of them) before the young hatched against those that only received recordings of parents’ normal contact calls during incubation. Both parents of the test brood the made the incubation call “only during the end of the incubation period and when the maximum daily temperature rose above 26°C (78.8°F).”

When the chicks hatched, those that had received the incubation calls were not only more vocal than the control nestlings, they also weighed less. Lower weight enables them to lose heat better than larger chicks and might also reduce damage from oxidation that can adversely affect reproduction, according to the article. And the lower-weight chicks went on to produce more fledglings themselves than control birds in the study.

“This is the first time scientists have found animals using sound to affect the growth, development, behavior, and reproductive success of their offspring, and adds to a growing body of research revealing that birds can ‘doctor’ their eggs,” the article notes. Incubation calls were first found to be used by another Australian songbird, the superb fairy wrens (Malurus cyaneus), but apparently to program chicks to use a “password” to solicit food.

Bolder is not necessarily better for tadpoles

On the nonavian front, researchers have found that bolder tadpoles are more likely to spread diseases to other frogs. According to a recent “Science” magazine article researchers infected native wood frog tadpoles in the lab with ranavirus, which causes disease in frogs and kills tadpoles. They found that “bolder larvae — those who moved faster toward food sources and spent less time swimming alone in the water — caused more infections than their passive peers.” Bolder tadpoles were also more likely to pick up an infection, perhaps because they had more interactions with infected peers.

Researchers have found that bold wood frog tadpoles like the one above are more likely to spread disease than more cautious ones.
Researchers have found that bold wood frog tadpoles like the one above are more likely to spread disease than more cautious ones. By Pam Owen

So why should we primates care? The research team is exploring the possibility of whether bolder behavior results in immunological trade-offs. “Identifying superspreaders may be crucial for preventing disease outbreaks, not just in amphibians, but in humans and other animals as well,” according to the article.

Art shows celebrate National Park Service centennial

The National Park Service (NPS) is celebrating its centennial birthday this year. Along with its regular ranger-led programs, Shenandoah National Park has been offering special events related to the centennial that run through the fall, as listed on its website.

Not on the list but worth checking out is an art exhibition by Middle Street Gallery members, “Centennial of the Parks,” which runs until Oct. 31 at the Skyland and Big Meadows lodges during their regular hours. A percentage of the price of sold artworks will be donated to the Shenandoah National Park Trust, according to the Facebook page of the Arts & Culture Center in Culpeper (ACC).

Two other artists’ groups are also celebrating the centennial through art. “Celebrate the Centennial,” by Firnew Farm Artists Circle, in Madison, opens Sept. 1, with a reception on Sept. 9, 6-9, and runs through Oct. 28. The show is open Monday-Friday, 9-5; Saturday and Sunday, 1-5, at Forest School’s Walker Fine Arts Center (898 Woodberry Forest Rd, Woodberry Forest, VA 22989) and features paintings, photography and pottery.

The ACC is sponsoring “Nation’s Natural Heritage” at the State Theatre in Culpeper. The show runs Oct. 20-Nov. 27, with an opening reception Oct. 20, 5:30-7:30. “The spectacular landscapes, flora, fauna, and wildlife of the United States’ National Parks have inspired artists in all media for the last century and will continue to be a catalyst for creative expression for another century,” says ACC’s Pam Stewart. The show also offers a chance to check out the wonderful restoration of this art deco building.

© 2016 Pam Owen

Pam Owen
About Pam Owen 340 Articles
Writer, editor, photographer, and passionate nature conservationist living in Rappahannock County, in the Blue Ridge Mountains of Virginia. Two favorite quotes: By E.O. Wilson, who coined the term "biodiversity," "Nature holds the key to our aesthetic, intellectual, cognitive and even spiritual satisfaction”; by Douglas Adams, “I love deadlines. I love the whooshing sound they make as they pass by.”