Little Book Cliffs Roundup, Day 7

The incident started on September 11. Results through September 17:

Scope: Little Book Cliffs HMA
Target: Horses
AML: 150
Pre-gather population: Unknown (not stated in news release)
True AML: N/A (no livestock grazing)
Type: Planned
Method: Helicopter
Goals: Gather 130, remove 100
Captured: 134, up from 116 on Day 5
Shipped: 78, up from 38 on Day 5
Released: None
Deaths: 2, up from zero on Day 5
Average daily take: 19.1
Unaccounted-for animals: 54

The figures above are based on the daily reports.

The helicopter was grounded on Day 7 due to weather, not because the capture goal had been reached.

Two horses were dispatched on Day 6 due to knee injuries, bringing the death rate to 1.5%.

The capture total includes 36 stallions, 78 mares and 20 foals.

Youngsters represented 14.9% of the animals gathered, consistent with a herd growth rate of nine to ten percent per year.

Of the adults, 31.6% were male and 68.4% were female, outside the expected range of variation from a random process centered at 50% males / 50% females.

Body condition scores were not given.

The location of the trap is not known.

Up to 20 mares will be treated with fertility control pesticides and be returned to the HMA with up to ten stallions.

The Draft EA for management actions in the HMA indicated on page 6 that the herd consisted of 203 horses, including 22 foals, as of September 2023. Of the 181 adults, 33% were male and 67% were female.

The Final EA states on page 6 that the population in July 2024 was 222, including 29 foals, and that the 193 adults consisted of 42% males and 58% females.

Abnormal sex ratios are common in herds treated with PZP, a restricted-use pesticide that tricks the immune system into attacking the ovaries.