Feathered Friends' two 20-degree bags, split by room and weight. The Swallow YF is the roomier, more comfortable cut with 900-fill down, and the Hummingbird UL is the trimmer ultralight version with even higher 950-fill down. Same rating, different priorities.
| Feathered Friends Swallow YF 20 | Feathered Friends Hummingbird UL 20 | |
|---|---|---|
| GearScore | 86 | 87✓ |
| Comfort rating | 30 °F | 30 °F |
| Weight | 29.2 oz | 23.9 oz✓ |
| Warmth-to-weight | 4.8 /100g | 5.9 /100g✓ |
| Packed size | 9.0 L | 9.0 L |
| Fill power | 900 FP | 950 FP✓ |
| Price | $589✓ | $639 |
| Fill | Down | Down |
| Style | Bag | Bag |
| Shape | Mummy | Mummy |
Highlighted cells mark the better spec: Swallow YF 20 in blue, Hummingbird UL 20 in amber. A blank spec is never counted as a win. A lower comfort rating in °F means a warmer bag, so the warmer bag takes that row. GearScore is the overall rating (0 to 100); re-weight it on the full bag comparison. Prices are current MSRP.
Feathered Friends builds these two bags to the same 20-degree rating but for different sleepers. The Swallow YF 20 is the roomier, more comfortable cut with 900-fill down, and the Hummingbird UL 20 is the trimmer ultralight version with even higher 950-fill down. Same temperature rating, different priorities.
The specs frame the choice. The Hummingbird is lighter and uses higher fill power (950 against 900), so it packs down smaller and carries easier, at a higher price and in a narrower cut. The Swallow gives you more interior room to move and a lower price, for a few more ounces. Both are hand-built in Seattle with premium goose down and share the same 20-degree comfort rating.
Pick the Hummingbird UL if you count grams and sleep fairly still; it is the lighter, higher-fill-power bag for ultralight trips. Pick the Swallow if you want more room to move and a bit of savings, and you do not mind the extra weight. Restless sleepers and anyone who feels boxed in by a tight mummy will appreciate the Swallow's cut; weight-focused backpackers will reach for the Hummingbird.
Room and weight. The Swallow YF has a wider, more comfortable cut and 900-fill down, while the Hummingbird UL is a trimmer ultralight bag with higher 950-fill down that weighs less and packs smaller. Both carry the same 20-degree comfort rating.
The Hummingbird UL, by several ounces. It uses higher fill power and a narrower cut to cut weight, which is the whole point of the UL line. The Swallow trades that weight for more interior room.
They share the same 20-degree comfort rating, so neither is meaningfully warmer. The higher 950 fill power in the Hummingbird buys weight savings, not extra warmth, at the same rating. Choose by room and weight, not warmth.