Feathered Friends Lark 10 UL Sleeping Bag Review

The Feathered Friends Lark 10 UL Sleeping Bag is a great sleeping bag for cold sleepers. With 950+ fill power goose down, a draft tube, and a thick draft collar, the Feathered Friends Lark is a very good bag for early spring and late autumn on most trails. I don’t like to augment my sleep system by wearing heavy clothes or jackets, so this a good sleeping bag for me. I’ve also used it on short winter trips when I’m confident of accurate weather predictions in the mountains, and this sleeping bag has kept me warm and comfortable

I also own an older Feathered Friends Lark 10, but upgraded to a new version of the same bag because it has a water-resistant Pertex Endurance shell that my older (and much used) Lark 10 lacked. I use a single wall shelter when thru-hiking that collects a lot of internal condensation and I wanted the extra moisture protection. At this rate, I may end up buying a third Lark 10 in the future if Feathered Friends keeps making sleeping bags at the same level of quality that they do today!

Specs at a Glance

• Temperature Rating: 10*F / -12.2*C
• Fill Power: 950 + Goose Down
• Size: Long 6′ 6″ / 198 cm (also available in 6′)
• Weight: 33.1 oz / 938 g (33.5 oz, actual)
• Fill Weight:  21.2 oz / 601 g
• Dimensions: 60″ / 56″ / 38″
• Packed Size: 11L
• Collar: Full collar
• Baffles: Continuous
• Sleeping Bag Shell Fabric: Pertex Endurance UL
• Lining Fabric: Flite 15 denier ripstop nylon
• Zip Side: Left
• Color: Grey/Blue
• Country of Origin: Made in Seattle, USA of imported materials

Shell/Lining

The Feathered Friends Lark 10 UL has a water-resistant Pertex Endurance shell, which is typically found on high-quality bags. It is slightly stiffer than the shell on my old Feathered Friends bag, but it is no heavier and packs down nice and tight. I’m excited to have the water-resistant Pertex shell since I use a Dyneema tarp tent that always struggles with condensation.

The Lark’s internal lining is a silky smooth 15 denier ripstop nylon. On the trail, I work hard to keep the interior material clean and soft, and always wear a clean set of “sleeping clothes” that I don’t use for hiking. These same “sleeping clothes” also serve as my “town clothes” when I go into towns for resupply, and often I’ll change into them before I “hitchhike” into town. They are much more presentable and less stinky than my hiking clothes. They help keep the sleeping bag cleaner, and drivers and townspeople are much happier to meet me.

Bag Weight / Fill Weight

The Lark 10 UL is insulated with premium 950+ fill power goose down. The bag weighs 33.5 oz, with 21.2 oz of that in the weight of the down insulation. At slightly over 2 pounds, there are very few 10 degrees sleeping bags at this weight and this level of quality. In fact, the only bag that even comes close is the Western Mountaineering Versalite which is also rated to 10*F degrees. It’s insulated with 22 oz of 850 fill power goose down with a total bag weight of 34 oz. Feathered Friends is the only sleeping bag maker I know of that makes all of their sleeping bags with 900 or 950 fill power down because it’s so insulating and lightweight.

Long Length Sizing

I typically choose a long length in all my sleeping bags and quilts, especially for cold temperatures. I am a total burrower, and if it is cold, I’ll burrow down and cinch a sleeping bag hood closed and only leave a small hole to breathe. I can do the same with quilts, but not as easily.

I also like to bring my battery and phone into the bag with me, along with a few clothes, on cold nights. A long bag provides me a little extra room for these sleeping partners, especially if my trail runners are brought into the bag to prevent freezing.

Hood and Draft Collar

The Feathered Friends Lark hood is perfect for both my oversized head and my small Hyperlite Mountain Gear pillow. I put the pillow inside the hood when it’s warmer, so it does not slide all over my sleeping pad. In colder temperatures, the pillow goes under the hood since I burrow. The hood on the Lark has plenty of insulation, it’s deep, and cinches up well when it is cold outside.

The big fluffy hood is augmented by a puffy draft collar. The collar has a cinch string just below the hood adjustment on the right side of the sleeping bag where they’re easy to reach and adjust. The left side of the collar by the zipper snaps onto the bag’s interior creating a snug and draft-free connection. Sometimes, I’ll cinch shut the hood, and push up the thick draft collar to cover the breathing hole, only leaving a very small space open. I only do this when I’m curled into the fetal position and really need to warm up fast!

Continuous Baffles

The baffles on the Lark circle the sleeping bag. I don’t personally consider these a necessity, and it is not all that easy to shift the down in the sleeping bag. I’ve attempted to shift down to the top of my bag when it is colder, but often find, after thrashing around all night, that it is right back where it started the next morning. The baffles are also only so wide, and there is not much room for the down to be bunched up on one side of the bag. Still, when it is cold or hot, it is nice to be able to shift the down, something you can’t do in a sewn-through sleeping bag.

Two-Way Zipper / Draft Tube

The Feathered Friends Lark 10 has a #5 YKK, two-way zipper with an “overlapping dual-webbing zip guard” that guides the zipper away from the fabric.  This is a nice feature, since snagging zippers can be very irritating, especially if the fabric gets damp or moist.  The two-way zipper also allows you to easily regulate temperatures in your sleeping bag, in case your feet get hot.  I have personally never had hot feet, but I know other hikers that have complained about their inability to cool off their feet.

The Lark 10 has an overfilled draft tube that runs beside the zipper to prevent air leaks and cold spots. The thing is huge and a lot larger than other cold-weather bags I’ve used in the past from Western Mountaineering, Montbell, and Marmot.

Why a Sleeping Bag vs a Quilt?

There are advantages to both sleeping bags and quilts, but as a cold sleeper, I prefer a sleeping bag when temperatures fall below 40 degrees. No matter how much I cinch my quilt up around my Neoair sleeping pad I will inevitably have a cold spot or two. I’m a “thrasher” and “tosser” and the quilts always seem to shift. I don’t have this issue with sleeping bags. No matter how much I fight that bag, it’s not budging.

On my upcoming thru-hike of the Arizona Trail, I chose to bring the Feathered Friends Lark 10 over my Nunatak Quilt,  because the AZT is a trail of extremes. You have the hot desert temperatures and the cold high desert nights. There are also high-altitude mountain elevations where you can encounter snow and single digits temperatures early in the season. I know I’ll be warmer with a sleeping bag than a quilt when it gets cold.

Women’s Sleeping Bags

I’ve occasionally been asked why I don’t use women’s sleeping bags instead of unisex (ie. men’s) models. In the case of Feathered Friends, which makes many women’s bags, their largest size for women is 5’9″. I’m 5’11″, so their women’s bags are too short for me.

Many women’s bags are designed with more down insulation in the foot box and over the chest. But I’ve never found that to be a significant advantage in a sleeping bag with continuous baffles, like the Lark. If I have a cold spot, I just shift some of the goose down in the bag’s continuous baffles to that spot. I also prefer the cut of men’s cold weather bags, which I find are slightly boxier than women’s and provide more room if I need to wear extra layers or decide to drag my electronics and clothes into my bag with me.

Comparable Cold Weather Sleeping Bags

Recommendation

You have listened to me gush enough about the Feathered Friends Lark 10 UL Sleeping Bag to know I highly recommend this bag. It is a great bag for colder weather that’s insulated with 950 fill power goose down, with a warm hood, puffy draft collar, and large draft tube. Feathered Friends sleeping bags are my goto for cold temperatures and I’ve not used any sleeping bags as well made or as true to their temperature rating as their bags.

Disclosure: The author purchased this sleeping bag.

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