Gear Review: Feathered Friends Lark UL 10 Sleeping Bag

My biggest fear heading into a 330-mile stretch of the Colorado Trail beginning in mid-September was facing the cold temperatures (and threat of snow).  Although September is typically fairly temperate in the foothills, there is no such guarantee at 12,000 feet, which the Colorado Trail spends plenty of time at or above (including a 30+ consecutive mile stretch above this elevation in the San Juans). Cold nights call for a warm bag, which is why I chose the Feathered Friends Lark UL 10 for this haul.


feathered friends Lark UL 10

The following specs are for the regular length, which I am.

Length: 6′

Dimensions: 60″ / 56″ / 38″

Fill Power: 950+ Goose Down

Fill Weight: 20 oz

Bag Weight: 2lb 0 oz

Lining Fabric: Flite 15 denier ripstop nylon

Shell Fabric: Pertex Endurance UL


Feathered Friends offers four male / unisex 10-degree bags (and two women specific models” ). The Lark UL 10 is the lighter version compared to the Lark Nano (because of its higher fill power down), and also lighter than the Raven UL 10 (which is a wider version of the Lark).  I am 5′ 11″, 175 lb., barrel chested, and found this bag to offer ample space for my needs.

The bag features a mummy design, draw string closure around the hood, a large down collar and uses a Pertex Endurance shell for water resistance.

feathered friends Lark UL 10


Weight / Warmth

This much warmth for 2 lbs. feels like cheating.  If this bag were tested for PEDs, I’m not confident it’d pass.  Luckily, I didn’t encounter any random drug testing on the trail, and was able to stay warm at 12,000 feet during the latter of September without having to break my back in the process.  The lowest overnight temperature we encountered was 17-degrees, and not once was I uncomfortably cold inside my bag.  In fact, most nights, I left the bag draped over myself like a quilt.  Point, 950+ down fill power.


Because this bag features both continuous baffles and a wide hood with a cinch, you can displace the down and open up the hood to avoid roasting on warmer nights.  As luck (or climate change) would have it, last year’s September was the warmest on record for much of Colorado, and the 10-degree bag was overkill on most nights.  At the end of the day, I’m too lazy to dedicate any energy to displacing the down, but for those with >0 nighttime ambition, a quick shake of the bag to adjust the down would serve wonders to keep you cool.  I simply stick a limb or two out of the bag- and maybe add a swig of whiskey for good measure.


More accurately, this belongs in the “not a con” section since I rarely have an issue with a sleeping bag being “uncomfortable”. In this case, however, I was a tad concerned that this bag would be too tight for my Tasmanian Devil torso.  As it turned out, this was a non-issue.  In fact, I think the tighter fit helped to reduce cold spots in the bag, although that’s hard say definitively.

Additionally, because I toss and turn a lot at night (no one is perfect), I prefer a sleeping bag over a quilt when cold temperatures aren’t something I’m prepared to battle.

Manufactured in the USA

Feathered Friends bags are made by a small team in Seattle, WA- if buying gear manufactured in the good ol’ USofA is your sort of thing.


Although I’ve only tested this bag for 330-miles (plus a couple of other overnighters), I have accelerated the durability testing curve with the smallness of my brain.  Not once, but TWICE, did I snag this bag on my tent’s zipper, without any ripping let alone signs of wear and tear.



Let me first say that I think this bag is a good value.  It’s cheaper than Western Mountaineering Versalite-10 degree bag, a company with a great reputation, AND the Lark uses a higher loft down.  It’s more expensive than the Z-Packs 10-degree bag, but this is a quilt hybrid, and after adding a down hood and draft tube to achieve comparable warmth, the price difference is negligible. That said, $549 is a lot of money, and realistically not within every backpacker’s budget.  You’re getting what you pay for here.

No Option for Water-Resistant Down

For those backpacking in humid regions, the option for a DownTek / DriDown / other hydrophobic down treatment would be a plus.  That said, this is a winter or near-winter bag, and humidity is not a winter issue.  Perhaps a more feasible complaint for their warmer bags?


If a 10-degree sleeping bag is what you seek, I can’t imagine a better option than the Feathered Friends Lark UL 10.  Ample warmth below freezing for only 2 lbs. is hard to beat. The $549 is a high price, but a good value relative to comparable bags.  For larger body backpackers, you may want to opt for the Raven UL 10, but most will likely love the Lark.

Check out the Feathered Friends Lark 10

Disclosure: the Lark UL 10 was donated for the purpose of review.

Affiliate Disclosure

This website contains affiliate links, which means The Trek may receive a percentage of any product or service you purchase using the links in the articles or advertisements. The buyer pays the same price as they would otherwise, and your purchase helps to support The Trek's ongoing goal to serve you quality backpacking advice and information. Thanks for your support!

To learn more, please visit the About This Site page.

Comments 1

  • Scott R. Sater : Jul 8th

    Hi Zach!

    I’m responding to your Feathered Friends Lark UL 10 Review nearly four years later. But it is relevant to me NOW, because I will likely buy this bag based on three things:
    *Your Review
    *My Correspondence with FF
    *One Additional Review

    I appreciate what you shared, your details, and especially your rugged test on the Colorado Trail.

    I’m about the same body shape as well. I wondered about the shoulder girth being adequate, but sounds like it will be.

    Marmot Pinnacle is no slouch, but for some reason their 15 degree temperature rating for me, and for my particular version just doesn’t keep me warm enough in the High Himalayas. It’s only summer when we do our India Trekking. But it gets into the upper 20’s, and I have been cold, cold, cold in what has typically been described by many as one of Marmot’s historic finest. I love that company, too. Their Marmot Dri-Clime is amazing. And they fixed my zipper for free even after 10 years! But…I think I need a warmer bag.

    So I have been looking at Feathered Friends, and in particular, the Lark.

    Thanks again for your fine review. Your details, your actual “in the field testing,” and your humor and upbeat demeanor made this a great read for me!

    All My Best!

    Scott Sater


What Do You Think?