![]() ![]() ![]() Producer: John Kessler Managing Producer: Jason Saul Associate Producer: Ellen Blackstone © 2018 Tune In to Nature. BirdNote’s theme music was composed and played by Nancy Rumbel and John Kessler. ML44839 GCKI G Keller ML108875041 CORA D Donnecke ML137574 CORA G Vyn. # Bird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Some days on a bird walk, especially in the northern states, you might see the continent’s tiniest and most massive songbirds in the same tree. Half the world’s 10,000 birds are in the songbird group. But the kinglet, with its lighter-than-air hovering flight, could literally fly circles around the raven. In a wrestling match, the raven would have an undeniable size advantage. Not just North America’s largest songbird, the Common Raven ranks as the world’s largest songbird. A gruff voice announces the biggest songbird, the Common Raven, almost two feet in length and weighing around three pounds. Golden-crowned Kinglets are a chubby three-and-a-half inches long, hummingbird sized, and weigh about as much as 6 shelled peanuts. You’re hearing the high whistles of a Golden-crowned Kinglet, one of our smallest songbirds. ![]() They aren’t all fine singers by any stretch, but “songbirds” sticks as a name. ![]() Which is the heftiest of all songbirds on the continent? What about the tiniest? Okay, first, what is a “songbird?” Songbirds make up a broad and seemingly informal category, from swallows and robins to crows, sparrows, and many more. Every Southern state has its favorite songbirds, and every state has a state bird (or two) that it celebrates. "Our study is a promising step to understand how the changes in gene regulation could eventually lead to the evolution of species-specific animal behaviors.Written by Bob Sundstrom This is BirdNote. "We believe that this isn't just about bird songs," the lead author, Kazuhiro Wada said. Another example is the Tinamous whose song. According to the authors, future research building on these findings could reveal the specific gene regulatory changes that underlie the evolution of species-specific learned behaviors. The thrush uses the birdsongs it has learned in different sequences and every time it improvises in a different way. These results demonstrate functional neurogenetic associations between inter-species differences in gene regulation and species-specific learned behaviors. This was supported by the fact that the use of a drug to over-activate BDNF receptors altered the activity of trans-regulated genes in the RA and disrupted the structures of learned songs in the adult zebra finch. They identified a signaling molecule called BDNF as a mediator of changes in trans-regulated of genes in RA, with a significant correlation between individual variation in the amount of BDNF and species-specific song properties. They found that trans-regulatory changes were more prevalent than cis-regulatory changes and tended to primarily affect the activity of genes involved in the formation of nerve connections and transmission of information between neurons in one particular song nucleus, "RA" - considered as birds' counterpart to the mammalian laryngeal motor cortex. They then identified genes whose activity in song nuclei is regulated in a species-specific fashion, either by changes in the genes' own regulatory regions ("cis-regulation") or by changes in other proteins that affect a gene's activity ("trans-regulation"). The researchers compared the songs of birds that had been taught the same species' song versus those that had only heard the other species' song this showed that the song learning was mostly regulated by species-specific genetic differences. This allowed them to examine the relationship between inter-species differences in gene expression and the production of species-specific song patterns. Other species such as cardinals, chickadees, titmice, goldfinches, and woodpeckers remain in Oklahoma all year. In the new study, Wada and colleagues made use of two closely related songbird species - the zebra finch ( Taeniopygia guttata) and the owl finch ( Taeniopygia bichenovii) - and also the hybrid offspring of matings between these two species. Songbirds acquire species-specific songs through learning, which is also thought to depend on species-specific patterns of gene activity in song nuclei - brain regions known to be specialized for vocal learning and production. Learning of most complex motor skills, such as birdsong and human speech, is constrained in a manner that is characteristic of each species, but the mechanisms underlying species-specific learned behaviors remain poorly understood. ![]()
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