The wild horse herd on the barrier island of Shackleford Banks added 14 foals in 2017, while losing five adults and one foal, for a net increase of eight horses. The population at the beginning of 2018 was 120 horses.
Fertility control has not been applied since 2009. The AML is 130 and the area where the horses roam covers 3000 acres, for an aimed-at population density of 43.3 animals per thousand acres.
No roundups are planned. Livestock are not present in the area.
Refer to the story in Coastal Review Online dated 09/04/18.
The report published by NPS indicated that, of the horses aged twenty years and older, 17 out of 20 are mares (85%). Assuming that mortality is evenly distributed among genders (p = .5), you’d expect to find between four and sixteen mares in the group, using np-chart limits with n = 20.
That you have 17 mares (and 3 stallions) suggests that mortality favors stallions at Shackleford Banks. This result should be attributed to a special cause.
The report did not say if any of the three stallions were band leaders.
Wild horse herds on the east coast barrier islands have been on U.S. soil longer than those of the American west.