San Miguel Island Closure
In the interest of public safety, the U.S. Navy is closing San Miguel Island until further notice due to recent concerns of possible unexploded ordnance. More »
Santa Barbara Island Closed Due to Storm Damage
Santa Barbara Island is closed to public access due to damage from the recent storms to the pier landing ladder. The closure will be in place until a new ladder can be fabricated and installed. The closure is expected to last over a month. More »
Public Closures on Santa Barbara Island
Certain Santa Barbara Island trails are closed to all public entry to proctect breeding populations of California brown pelicans. More »
Western Harvest Mouse
Quick and Cool Facts
On Santa Cruz Island, their distribution was previously thought to be limited to the marsh area at Prisoner's Harbor. Recent surveys found them to be much more widely distributed on the island, but at relatively low numbers (especially when compared to the numerous island deer mice), due to their need for dense grass or herbaceous cover (which is patchily distributed on Santa Cruz. The species is more numerous on Santa Catalina Island, which may be an indication of that island's recovery from non-native grazers.
The western harvest mouse has a high potential reproductive rate. Females can breed at 4 months of age. It births litters averaging 4 young, but ranging anywhere from 1-9 young. The female is able to become pregnant more than once a year, with a gestation period of 23 or 24 days. It breeds throughout the year with the exception of late winter in the southern part of its range. In northern parts of its range, this harvest mouse breeds only in late spring and summer (usually 2-3 litters).
The young weigh ½ ounce or less at birth and are naked, pink, and blind. The mouse's eyes open 10-12 days after birth and they are weaned 19 days after birth. The western harvest mouse goes through 3 pelages: juvenile, sub-adult, and adult. The juvenile pelage is rather wooly and dull grey. The adult pelage is relatively brighter. Molting starts on the ventral surface and spreads over the flanks to meet on the back. A second point of origin is on the muzzle, the new coat spreads back forming a molt line behind the ears. This specie molts once annually during the summer.
In 1998 the California Department of Fish and Game considered the species to be one of special concern.
The recent removal of feral pigs from Santa Cruz Island should improve habitat for harvest mice, which may become more widely and densely distributed on the island.
Did You Know?
Channel Islands National Park has more endangered species that only exist within this park than any other unit of the National Park Service. This means that survival of these plants and animals depends entirely on our ability to protect and restore the habitat of the five park islands.