The Park Service found 22 stallions and 54 mares on the Maryland side of the island in September, according to a story published today by WBOC-TV of Salisbury, MD.
One death was reported since the last census but no births.
Not noted in the report was the abnormal sex ratio of the herd, roughly 29% males and 71% females. The range of variation attributable to natural causes for a herd this size is 33% to 67%. Both of the observed values fall outside these limits.
The upper and lower limits were computed with basic statistical formulas, where n = 76 and p-bar = .5. The chart says ‘Look for an assignable cause.’
Could it be the contraceptives that have been applied to the herd for the last 25 years?