In Pokemon GO's Holiday Part 1 branching research, trainers face a crucial decision: aid Spark or Sierra. While Niantic's official announcement omits details on this free research (available December 17-22, 9:59 AM local time), the choice impacts which Pokémon you'll prioritize.
Choosing Your Path: Spark or Sierra?
The core difference lies in the Pokémon types: Ice (Spark) or Fire (Sierra). The final reward (Sandygast) remains consistent, but the path's encounters vary significantly.
Spark's Ice-Type Challenge:

Choosing Spark directs your efforts towards Ice-type Pokémon. Completing Part 2 rewards an Alolan Vulpix encounter.
Part 2:
| Research Task | Reward | 
|---|---|
| Catch 10 Ice-Type Pokemon | 10 Pinap Berries | 
| Take 5 snapshots of different wild Pokemon | 20 Poke Balls | 
| Complete 5 Field Research Tasks | 500 Stardust | 
| Complete All Three Tasks | Alolan Vulpix, 2000 XP | 
Part 3:
| Research Task | Reward | 
|---|---|
| Catch 25 Ice-Type Pokemon | 10 Ultra Balls | 
| Power Up Ice-Type Pokemon 10 Times | 1 Golden Razz Berry | 
| Collect MP from 3 Power Spots | 100 Max Particles | 
| Complete All Three Tasks | Sandygast, 3000 XP, 2000 Stardust | 
Sierra's Fiery Pursuit:

Opting for Sierra focuses on Fire-type Pokémon, culminating in a Shadow Vulpix encounter in Part 2.
Part 2:
| Research Task | Reward | 
|---|---|
| Catch 10 Fire-Type Pokemon | 10 Pinap Berries | 
| Take 5 snapshots of different wild Pokemon | 20 Poke Balls | 
| Complete 5 Field Research Tasks | 500 Stardust | 
| Complete All Three Tasks | Shadow Vulpix, 2000 XP | 
Part 3:
| Research Task | Reward | 
|---|---|
| Catch 25 Fire-Type Pokemon | 10 Ultra Balls | 
| Power Up Fire-Type Pokemon 10 Times | 1 Golden Razz Berry | 
| Collect MP from 3 Power Spots | 100 Max Particles | 
| Complete All Three Tasks | Sandygast, 3000 XP, 2000 Stardust | 
Your decision hinges on your preferred Vulpix variant and the Pokémon type you wish to concentrate on during the Holiday Part 1 event. Pokemon GO is currently available.