On Tuesday, folk-rock quintet The Mammals returns to the Bayside Grange to herald the release of their latest album, “Departure.” Wielding the combined power of Appalachian fiddle-banjo alchemy, their own contemporary lyric poetry, and some enviable Seeger and Ungar folk genealogy, The Mammals promise a show that includes something for everyone.

Unlike their live shows and past Mammals albums, there is no traditional music on “Departure.” There aren't really any foot-stompers. And the politics, while still present in many of the songs, are subtler, lurking powerfully below the surface. While you can still catch the band's folky roots showing through in parts, the new album features noticeably more rock moments.

”Departure could easily get put in the rock section of a record store, yet the instrumentation of the band hasn't changed much,” says band member Tao Rodriguez-Seeger. “We added some organ sounds and a few electric guitar overdubs, but for the most part, its fiddle, banjo, guitar, upright bass, drums and lots of singing. I'm most happy with the way it just sounds like a damn good band at the peak of their creative process.”

The Woodstock, NY-based Mammals, who formed in 2001, refuse to stand still musically. That they have thrived in the midst of a widespread old-time, neo-traditional movement indicates the open-mindedness of that community. The Mammals, a mainstay at major music festivals, are renowned for unpredictable live shows and high-energy festival sets. And the band's songwriting achieves new heights on this album.

”Follow Me to Carthage,” which leads off the album, is a melodic and powerful long-viewed gander at history repeating itself. “Alone on the Homestead,” sung from the voice of a woman who has lost her entire family to a war, is a timeless protest song and hauntingly beautiful. Michael Merenda, who wrote the ballad, sings the gender-bending lead vocal, with Ruth Ungar adding harmony.

On “Kiss the Break of the Day,” a wonderful song about traveling the USA, and “Tryin' to Remember What City I Know You From,” two more Merenda-penned songs, Ungar gets the lead vocal call. She soars.

With songs about the brutal effects of war and the costliness of consumer ignorance (”Silk Song”), this is at least in part a political album, though it shows a quieter kind of politics than the band has displayed in the past. “I don't think of it so much as 'We're a political band,' as much as we are a politically aware group of artists,” says Merenda. “The political environment of our country, and the world for that matter, has been anything but subtle during the past six years, and that atmosphere, those stories, is undoubtedly going to make their way into our songs.”

On “Departure,” the band covers the famous South American protest anthem “Sólo le pido a Dios,” and the country ballad “Satisfied Mind.” They also reinvent songs from artists as diverse as Morphine (”Do Not Go Quietly Unto Your Grave”) and Nirvana (”Come as You Are”.)

”We've modernized old songs before, but this time we got to coax a contemporary song backwards a little bit,” says Ruth Ungar, who takes the lead vocals on the band's somber version of the already-dark Nirvana tune. “Tao's harmonica and Chris's drums create solid edges, and I sing it gently, take the edges off.”

”When I hear the album, I am struck by the calm,” she says. “There are dynamic arrangements and hard-hitting lyrics, but nothing jerky or out of control. Our previous records have more reckless abandon. This one is more polished and more heartfelt.”

The Mammals perform Tuesday at the Bayside Grange. The Humboldt Folklife Society opens the doors at 7:30 p.m. and the show begins at 8 p.m. Tickets are $10 for HFS members and students, $12 general. Advance tickets are available (and recommended) at Wildwood Music, The Metro and the Works in Eureka and Arcata. For more information, visit www.humboldtfolklife.org or call 822-5394.