One colony can be observed in the Spring along McAllister Creek in the Nisqually Wildlife Refuge. Several large colonies are located in south Puget Sound. Great Blue Herons nest in large groups in tall trees near the water. The Great Blue Heron feeds mainly during the day, but occasionally will hunt at night. They even eat mice and other small mammals while patrolling open fields. When fishing in freshwater, herons eat frogs, fish and crayfish. To avoid getting spines or fins stuck in its throat, the heron shifts the unlucky dinner to a head-first position and then swallows. When prey is spotted, the neck unfurls hurling the head forward with lightening speed grabbing the unlucky meal. Hatching occurs after 23-25 days with the young immediately leaving the nest. They often nest far from water, where they build a concealed nest of dry grass and plant stems. Like other dabbling ducks they tend to nest earlier in the season, risking impacts from late winter storms. They leave in early spring for their inland, freshwater breeding sites. including as far north as northern Alaska and both the western and eastern parts of Canada. and Mexico including the Caribbean Islands. The American Wigeon ranges throughout North America with winter sojourns to the southern U.S. In addition they also come up on lawns to eat the grass. The other interesting aspect of their behavior is that they feed heavily on marine vegetation, mainly Sea Lettuce, during their winter layover. The call is very unusual and fun to listen to. While feeding along the shoreline they communicate with other flock members using a high whistling call. Hybridization between the species regularly occurs. The Eurasian Wigeon male has a dark rufus head with a muted white crown. However both males and females will occasionally stray south to Puget Sound. "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.A close cousin, the Eurasian Wigeon, normally winters in the Aleutian Islands and Bering Sea. "We believe that this isn't just about bird songs," the lead author, Kazuhiro Wada said. 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. 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.
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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