The Hummingbird is almost magical for the warmth and comfort it provides in such a lightweight package. Although it ultimately missed out on the Editors' Choice Award, it still deservedly earns our Top Pick for Light and Fast Adventures. The competition was extremely close so it's vital to weigh the pros and cons of our top-rated bags to ensure you pick the perfect one for you.
Performance Comparison

Recording our thoughts during a field test with the Feathered Friends Hummingbird.
Photo: Jack Cramer
Warmth
The Hummingbird UL contains 12 ounces of ultra-premium, 950+ fill-power, goose down. Although this is a little less insulation than other primo bags with similar temperature ratings, it has a narrow fit that requires less material to provide the same amount of warmth.
Feather Friends does put their sleeping bags through formal EN temperature
testing. Instead they supply their own manufacturer rating for the Hummingingbird of 30°F. We felt it provided similar warmth compared to the average bag that receives an EN lower limit rating of 20°F. With this level of insulation, it's an excellent middle-of-the-road bag that's well-suited for all but the coldest or warmest 3-season uses.

The Hummingbird's 30F rating is generous compared to other bags. We think it's warm enough for cold spring and fall nights.
Photo: Jack Cramer
Weight
Weighing in on our scale at 1.45 pounds for a size long, the Hummingbird UL is truly ultralight. This is made all the more impressive when you consider its substantial insulation and sturdy, full-length zipper that provide significant warmth and versatility, respectively.
On paper, their are a few bags with reported weights and temperature ratings that would seem to offer even better warmth-to-weight ratios than the Hummingbird. Our testers, however, found many of the temperature ratings on these competing bags to be overly optimistic. The Hummingbird's insulation, in contrast, felt much warmer than its 30° rating. We, thus, consider this bag to be the top bag in warmth-to-weight ratio and have trouble attributing this outstanding performance to something other than sorcery.
Comfort
Our only significant complaint with this bag is its comfort. Don't get us wrong, the fabric is soft, and the incredible loft of its ultra-premium down creates an extremely cozy cocoon. Rather, our comfort complaint is due to its narrow fit.
With 58 inches of shoulder girth, the Hummingbird is one of the narrowest bags we tested. Virtually all of our testers are happy inside bags that are 64 inches wide, but as the girth shrinks complaints steadily rise. Our larger and side sleeping reviewers, in particular, said the Hummingbird felt constrictive. This probably isn't a problem for shorter trips, when the benefits of less weight can overshadow the drawbacks in comfort. However, for longer trips, or over the full lifetime of a bag, the review team felt that the average user would likely prefer a wider design.

For some sleeping styles, the comfort difference between a narrow bag like the Feathered Friends Hummingbird (orange) and a wider bag can be substantial.
Photo: Jack Cramer
A smaller complaint about the Hummingbird's comfort related to the nosiness of its Pertex Endurance shell fabric. When manipulated, this fabric creates a distinct crinkling sound. Although it's only subtly louder than most other bags, some lighter sleepers felt the difference was enough to disturb their sleep.
Packed Size
Like its low weight would suggest, this bag packs down pretty small. With the help of an aftermarket compression sack, it achieved an impressive 7.3 liters in compressed volume. This is slightly larger than some bags with less insulation, but nearly identical to any other bag offering a similar level of warmth.
The simple drawstring stuff sack this bag comes with is ultralight, at just 0.8 oz, but not super effective at compression. To fully enjoy the Hummingbird's small packed size you will need to get a third-party compression sack. This will set you back an extra twenty bucks but will shrink its packed size by roughly 20%.

The Hummingbird is pretty bulky packed inside the yellow stuff sack that it comes with. A good compression sack, however, can compress it considerably smaller.
Photo: Jack Cramer
Versatility
The Feather Friends bags we tested feature some of the longest zippers in the backpacking sleeping review. These allow the Hummingbird to vent excess heat as well as any other bag we tried, expanding the range of temperatures it can comfortably be used in. When opened fully, the long zipper also effectively turns the bag into a quilt for sharing on a chilly morning or between climbing partners during a "light and fast" bivouac.
Its one versatility drawback is its down insulation. Like all down products, this down will lose its ability to insulate if it gets wet. Thus, this bag is not well-suited for particularly wet climates or activities.

Continuous horizontal baffles allow you to move feathers to the top or underside of a bag to adjust the amount of insulation.
Photo: Jack Cramer
Features and Design
Although it's just a simple mummy bag, we like this bag's features and design. The zipper, as we mentioned above, is super long for venting excess heat.
It also incorporates an effective anti-snag zipper slide. The fabric adjacent to this zipper is stiffened by an internal strip of flexible plastic that further reduces the likelihood that fabric will get caught in the zipper's teeth.

The Feathered Friends bags that we tried feature a Y-shaped zipper slide and an internal strip of flexible plastic to prevent the zipper from snagging.
Photo: Jack Cramer
We also prefer the hood design on this and other Feathered Friends bags compared to some of their closest rivals. Placing the hood's drawstring slightly back from the hood opening creates a cozy tube of insulation around the face that our testers found to be warmer and more comfortable.

The snap that seals the Hummingbird may be simple but it's easy to snap and effective at keeping it closed.
Photo: Jack Cramer
Value
Although the Hummingbird certainly isn't cheap, it does cost a little less than similarly performing bags. If you're going to spend several hundred dollars on an ultra-premium sleeping bag, however, this meager savings probably isn't worth factoring into your decision. Instead, simply choose the ultra-premium bag that's best suited for your sleeping style and expected applications. Whether that's the Hummingbird or one of its competitors, you will receive an expensive bag that still provides an exceptional value because it can last for over a decade.

The Hummingbird is our favorite backpacking sleeping bag for when we want to go light. Pair it with a backpacking tarp to really trim the weight of your overnight kit.
Photo: Jack Cramer
Conclusion
The
Feathered Friend Hummingbird's greatest strength is its incredible warmth-to-weight ratio. We also think the long, anti-snag, zipper performs better than any other, giving this bag an edge in convenience and versatility. However, the narrow dimensions that contribute to this bag's low weight come with drawbacks for its comfort. Larger and side-sleeping testers found these dimensions to be uncomfortably constrictive. The Hummingbird is thus our Top Pick for users interested in "fast and light" missions where sacrificing some comfort for lower weight is often worth it. The average backpacker, however, may prefer a slightly heavier bag with more roomy dimensions.