zebra finch

Adult Birds Use "Baby Talk"--and Babies Pay Attention

New research shows not only that baby birds learn songs best if they're tutored, but that adult birds seem to modify their songs the way we humans use baby talk. Further, activity in the babies' brains may have implications for research in attention issues in people. 

Birds do not hatch knowing how to sing. Like humans, they need to learn how to vocalize in socially meaningful ways. While it is known that baby birds learn from adults, Jon Sakata and his team of biologists at McGill University wanted to find out whether an adult needs to be present for the best learning or whether simply hearing the song is enough for baby birds. In other words, they wanted to find out whether the social connection matter when it comes to teaching.

For this study, male Zebra Finch chicks were observed learning songs from adult males either in person or by recording. (Why Zebra Finches? Because they breed well in the lab. And why just males? Because the males are the primary singers of the species.) The chicks, who had been cared for only by females prior to the study, were exposed for varying amounts of time to males singing in two different conditions. One group of chicks were tutored by a male in person; the other heard him singing to chicks in another room. The results? The chicks tutored in person learned their song more accurately no matter how long they were exposed to it. Further, the chicks who paid the most attention learned the best.

But the chicks weren't the only ones paying more attention. The males doing the tutoring took extra care when singing to their pupils. They repeated the beginning of the song, slowed down their phrases, and cleaned up some stray sounds. If you've ever spoken to a young child, you know exactly what these adults did. Further research is needed before anyone knows whether the adult males made these changes deliberately.

One last item of interest: the brains of the chicks who learned in person showed activity in two regions that showed no activity in the chicks who learned by recording. That is, the social activity of being taught in person seemed to activate mechanisms for attention. The research continues in order to identify just what those mechanisms might be.

What to know more? Read the abstract of the original study in the Proceedings of the National Academy of Sciences. The Washington Post has a nice article, too, complete with sound samples.

Birds of a (Red) Feather

Red birds stand out more than birds of other hues, so they get eaten more often than their drab relatives. So is having red feathers a good idea? And what makes birds red in the first place?

Recent research indicates that there are, in fact, advantages to being red, and they go far beyond being pretty to look at. It has been known for some time that birds with red feathers often have extra-sensitive cones (color-sensing vision cells) in their retinas, which may make it possible for them to see food sources that other birds can't. Some red birds have also been found to have cells in their livers that help with detoxification of harmful substances, potentially allowing their owners to eat a wider variety of foods than non-red birds. Perhaps because of these two advantages, birds with red coloring are more desirable mates than their non-red buddies in multiple species. 

So how does red happen? 

Recent research from the University of Cambridge, published in the journal Current Biology, indicates that some Zebra Finches possess a gene that allows them to convert yellow pigments in their food, called carotenoids, into a red coloring in their beaks. Interestingly, the red pigment exists at lower—almost undetectable—levels in regular, yellow-beaked Zebra Finches. 

A separate research team out of the Universidade do Porto of Portugal is working on the genetics of the red canary, a hybrid developed by canary fanciers about 100 years ago by interbreeding with the Red Siskin. One particularly intriguing finding is that the gene for carotenoid-to-red conversion exists in many, if not most, bird species, even if those birds don't appear red. The birds that aren't red still have the super-sensitive color vision and heavy-duty liver function conferred by the gene, but for some reason as yet unknown, they just don't have red skin or feathers. 

Why research red coloration in birds? Two reasons. First, it's a trait that easy to track and manipulate. Second, it's beautiful. 

Nest-Building Lessons

Most birds build nests, but how do they know how to build them? It's not like there are published blueprints. Very little research has been done on how nest-building birds know what they know, but here's an intriguing study. 

Male Zebra Finches build circular, domed nests for their mates and chicks. New research at the University of St Andrews, Scotland, shows that Zebra Finch males learn to build these nests at least partly by watching other Zebra Finch males. However, they'll imitate only the males they know. 

Scientists in the School of Biology paired up female Zebra Finches with males who had never built a nest. Each pair watched the male of another pair build a nest; this male was either known to them or a stranger. While building, this male used pink or orange string, colors that Zebra Finches don't normally use. (How they got him to use those colors isn't explained. Our guess is they had him read a 1970's issue of Architectural Digest.)

When the time came for the newbie nest-builder to build his first nest, he used the same color string as the male who demonstrated--but only if the demonstrator was a familiar bird. If the demonstrator wasn't, then the newbie did not make the same color choice. 

The experiment showed that birds will turn to public information when they need to decide which materials to use to build their first nest, but only if they know the individual who provided the information. We think birds could teach human students a thing or two about doing research for school papers with Google. 

Dr Lauren Guillette of the School of Biology, lead of this study, suggests that birds might learn from one another in a way that resembles human beings' learning culture.  "This is called ‘social learning’, and can save time and effort for first-time nest-builders....Perhaps surprisingly, the birds did not always use this ‘advice’, especially if it came from a stranger. In humans, learning from those we know is one way that cultural traditions are formed, from the tools we use to the clothes we wear or the music we listen to.”

Want to read the original article? Find it here. 

Scrambling Eggs' Incubating Temperatures

New research indicates that climate change may affect the development of embryos in birds' eggs, especially if the birds live in a hot climate.

A team of scientists at Australia's Macquarie University studied the effects of warming atmospheric temperatures on in-the-egg development of wild Zebra Finches, Taeniopygia guttata (yes, we're discussing Zebra Finches again).    In the wild, the Zebra Finch breeds in arid and semi-arid regions throughout Australia where atmospheric temperatures regularly exceed 96.8◦F. Like all birds, Zebra Finches can lay only one egg per day. They don't start incubating them until the clutch is complete, which takes about five days.

All the eggs are incubated equally, and they tend to hatch on the same day. Why does this matter? Because the chicks who hatch first grow big first, depriving their smaller siblings of resources. 

The Australian research team suspected that warm temperatures might cause problems during the egg-laying, pre-incubation stage. If the ambient temperature were to become warm enough for eggs to develop even without an adult sitting on them, the earliest-laid eggs would hatch earliest.  They were also concerned that Zebra Finches might be reaching the upper edge of their tolerance for high temperatures--in other words, that heated eggs might not hatch at all.

To test the prediction that warmer nest temperatures trigger early development, the team set up “hot” and “cool” experimental nest chambers. Thirty-three eggs from eight clutches were removed from their parents' nests on the day they were laid and placed into one of the four chambers. They were kept cool or warm while their sibling eggs were laid, then returned to their parents, who incubated the entire clutch until hatching. 

All the experimentally treated eggs hatched following their return to the parental nest, no matter how they had been treated--that's the good news: even the "hot" eggs survived. Overall, the average developmental time was 13 days — shorter for eggs that had been placed in the “hot” nest chambers. Also, as predicted, the eggs laid early in the laying sequence developed and hatched sooner.

Now the bad news: the time to hatching was similar for eggs placed in either the natural nest chambers or in the nest-box nest chambers--just 13 days, when 14 days had been expected. In other words, even though the heat-treated eggs hatched first, ALL the nests were "hot" enough to hatch fast.

What does this mean? That the nests of birds in hot climates are already affected by climate change, and they might suffer more if temperatures increase.