Bighorn on the Greens - Spring 2015
We hear stories throughout the year about bighorn sheep sightings on four golf courses in La Quinta (Tradition, SilverRock, PGA West and The Quarry). Most people are excited to see the sheep and some mistakenly think that the sheep need these urban areas, especially during the drought. We understand this concern, but hope readers will realize that it is not good for the bighorn to be down in the urban areas; the sheep do not need the golf courses. They need to be in the wild where they survive best.
We know this because we conducted two previous mortality studies on an adjacent herd of bighorn sheep. They regularly utilized the urban areas of Rancho Mirage since the 1950s, when Thunderbird estates was built in an alluvial fan used by the sheep. We found that 34% of the adult bighorn and 43% of the lambs died from the effects of urbanization during our studies. The sheep were killed by auto collisions, non-native toxic plant ingestion (oleander), wire entanglement, and drowning in swimming pools. In addition, we found strongyle intestinal parasites in 86% of the adult bighorn tested during our study. These parasites typically do not persist in the dry desert, but thrive on watered lawns. Our research findings led the City of Rancho Mirage to voluntarily put up a bighorn exclusion fence. Completed in 2002, this 4 mile, 8 feet high chain-link fence has eliminated urban-related bighorn deaths in the Rancho Mirage area and promoted recovery for this endangered species. Since the fence was finished, 12 years ago, the bighorn population has increased, in fact, this herd reached its recovery goal of 25 ewes just 2 years after the fence was completed. Lamb recruitment (survival) has doubled, the number of deaths has significantly decreased and the sheep have shifted their habitat use away from the urban setting and are utilizing historic habitat.
In neighboring La Quinta, rams have been attracted down to the aforementioned golf courses since 2007, to eat the lush lawns. By 2012, ewes and lambs began utilizing these golf courses as well, which has compounded the problem. Ewes pass home range information (where to eat, drink, etc.) down to their lambs so the lambs are being taught
that the golf courses are a "normal" area to live. They will then teach their offspring to use the golf courses as well. These golf courses were built in alluvial fans and wash bottoms that the bighorn have used for centuries. With recovery of this endangered species underway, the sheep are seeking out historic feeding sites, which are now urban areas. They are straying into the streets posing serious safety issues to them and humans.
There are only a handful of bighorn sheep radio-collared in the La Quinta area, out of over 100 sheep, so no one knows how many sheep have died for sure. We do know that at least 4 rams have died in the past 3 years as a result of coming down to these golf courses, 3 drowned, 1 ate oleander. Aside from the obvious issues, such as mortalities, sick lambs (disease can spread rapidly when unusually large groups of bighorn congregate as they do on the golf courses), intestinal parasites, drowning, toxic non-native plant ingestion (oleander), there are other issues facing the sheep that use the urban areas. They have an increased risk to predation, especially the further they stray from the mountainous escape terrain, exposure/ingestion of fertilizers, pesticides and herbicides, as well as habituation to human disturbance, which makes them less fit for survival.
These are desert bighorn sheep and they are incredibly adapted to live in the harsh desert environment, even in times of drought. Bighorn have many physical adaptations that allow them to utilize scant amounts of moisture from being ruminants and "chewing their cud" to their water-depleted pellet droppings. Bighorn can go 3 days without drinking water in the high summer heat and months without drinking in winter.
It is wrong to continue to subject these sheep to urban threats; they need to be kept off of these golf courses and move back to their natural habitat where they can continue to thrive into the future.