Washington Chapter | Foundation for North American Wild Sheep ( FNAWS )

Tucannon Herd

Population Status and Trend Analysis
The Tucannon herd is one of five bighorn sheep herds residing in the Blue Mountains. This herd was not exposed to the Pasteurella die-off that occurred in 1995-96. The population objective for this herd is to sustain a bighorn sheep population of 50-70 animals.

The population of the Tucannon herd has experienced a steady decline over the past five years. The last hunting permit was issued in 1999. The hunters interrupted a mountain lion attack on a ewe one evening. The following morning the ewe was found dead from the attack and buried by the mountain lion a short distance away. A necropsy revealed a severe case of scabies. Predation and poor escape terrain is believed to cause the population fluctuations experienced over the last 25 years by the Tucannon herd.

Lamb survival has been very low and the subsequent recruitment has diminished the number of rams and ewes to less than 20.

Habitat Condition and Trend
Habitat conditions on the Wooten Wildlife Area are excellent, but yellow-star thistle is moving into the area, and it is a constant battle to keep it from spreading. Weed control is the major habitat project at this time.

Disease and Parasites
The Tucannon herd has not been exposed to the Pasteurella die-off that occurred in other bighorn sheep populations in the Blue Mountains. Domestic goats have been observed running loose on WDFW land four miles north of the Tucannon herds range. This could be significant to this bighorn population.

Scabies appears to be of major concern to this herd and could be one of the reasons for the steady decline in the population. It is believed that bighorn sheep, particularly rams, may move between the Wenaha and the Tucannon herds. This may have resulted in the spread of scabies and possibly extend the impact of the Pasteurella die-off. This herd was originally composed of California Bighorns; the exposure to the Rocky Mountain Bighorns from the Wenaha could explain the cause of the current trends.

Management Conclusions
The Tucannon herd is experiencing a severe population decline as very few bighorn sheep were observed during March aerial surveys in 2002. The management objective will be to return this bighorn sheep population to 50-70 animals. Assessment of the current trend needs to be thoroughly examined.

Tucannon Rams, 1997	Tucannon, 1997	Tucannon, 1997
November 1998	November 1998