level could not become excessive. The flow device, as of 2013, was controlling the water level well. A keystone species, the beaver have transformed Alhambra Creek from a trickle into multiple dams and beaver ponds, which in turn, has led to the return of steelhead trout (Oncorhynchus mykiss) and river otter (Lontra canadensis) in 2008, and mink (Neovison vison) in 2009. Examples of the impact of the beaver as a keystone species in 2010, include a green heron (Butorides virescens) catching a tule perch (Hysterocarpus traskii traskii), the first recorded sighting of the perch in Alhambra Creek, and the December arrival of a pair of hooded mergansers (Lophodytes cucullatus) (see photos). The beaver parents have produced babies every year since their 2006 arrival. In November, 2009 the Martinez City Council approved the placement of an 81-tile wildlife mural on the Escobar Street bridge. The mural was created by schoolchildren and donated by Worth a Dam to memorialize the beavers and other fauna in Alhambra Creek. In June, 2010, after birthing and successfully weaning triplets that year (and quadruplets the previous three years), "Mom Beaver" died of infection caused by a broken tooth, as confirmed by necropsy. In 2011, a new adult female arrived at the creek and has given birth to three beavers. Flooding, following heavy rains, washed away the beaver lodge and all four dams on Alhambra Creek in March 2011 In September, 2011, Martinez officials ordered Mario Alfaro, a local artist commissioned to paint an outdoor mural celebrating the heritage of the city, to paint over the depiction of a beaver he had included in his panorama. He complied and also painted over his own name in apparent protest. In 2014, the beaver population of the creek was seven. From 2006 to 2014, a total of 22 beavers lived in the creek at various times; of these, 8 died, 7 are still living in the creek, and the fate of the other 7 is unknown. From 2008 to 2014, there has been an annual Beaver Festival in Martinez. History of the Martinez beavers The Martinez beavers probably originated from the Sacramento-San Joaquin River Delta. Historically, before the California Fur Rush of the late eighteenth and early nineteenth centuries, the Delta probably held the largest concentration of beaver in North America. It was California's early fur trade, more than any other single factor, that opened up the West, and