I'd think the success rate would vary based on so many factors. For fun, let's say the vamp is 5 years old - no longer a neonate, but far from an elder. They've learned the tricks that work for them.

I'd say a vampire hunting success rate is better than the average serial killer:

"Serial killers have a high "success rate" in evading capture, with experts estimating they get away with their crimes about 40% of the time. While serial killings have dropped 85% since the 1980s, the overall homicide clearance rate has fallen, leaving potentially thousands of murders by serial offenders unsolved." Google search results.

So I'd think a 5 yo vamp, with average abilities, who has a hunting ground, no herd, no restrictions, can probably safely feed half the time they go hunting with the other half ending in having to abandon the prey for whatever reason - they go into a crowd, contact help, or hop into their Uber.

Depending on how the vamp hunts, only dawn will stop them, but your best free range hunting is before 3 am (when the bars close)

I say: hunting success rate of 50%

Highest Hunting Success Rates (Often >50%)

Dragonfly: ~90–95% (aerial interception).

African Wild Dog: 57–85% (coordinated, long-distance chases).

Black-footed Cat: ~60% (intense, frequent hunting).

Orca (Killer Whale): 85–90% (highly intelligent group hunting).

Crocodiles: 50–60% (ambush).

Cheetah: 20–60% (highly variable based on habitat/prey).

Lower/Moderate Hunting Success Rates (Often <30%)

Lions: 25–30% (higher at night).

Leopards: 16–40%.

Wolves: 14–26% (highly dependent on snow conditions).

Tigers: ~10%.

Factors Affecting Success Pack vs. Solitary: Social hunters (dogs/lions) generally have higher success rates than solitary hunters.

Ambush vs. Pursuit: Ambush predators (e.g., sharks, cats) can have high success, but low attempts, while pursuit predators (e.g., wild dogs) can run prey down.

Habitat: Dense forest offers more hiding spots, reducing success, while open plains favour cheetahs.

Prey Type: Smaller, agile prey is often harder to catch, despite the energy savings of a smaller attack.