I am a MUFON Field Investigator, currently inactive, and a lifetime member. On the night of August 7th, I was at the Bocco Mtn BLM Recreation site NW of Wolcott CO, Lat.39'44"29.35N, Long.106'42"21.14W. I often go here to do sky watches as there are no visible lights that can be seen from here, and it is also an area where there have been a lot of UFO sightings over the years. I parked my pickup truck facing east, and I was sitting in the cab with the motor off when at about 2235 I observed a bright light rise from behind a ridgeline to the east. The ridgeline is about 8900' and 9-10 miles away. At first I thought it could be an aircraft on approach to the Eagle County airport, which is about 14 miles west. As I come out here often I have seen aircraft in this area with landing lights on that pass to the south of this location.As I watched the light ascending, still thinking it might be an aircraft, a second light came over the ridge that looked identical to the first. I now thought this was strange to see two aircraft approaching at the same time. As the second light ascended following the first one, the first blinked off as if someone had thrown a switch. As I have seen similar UFOs behave in this manner, I got out of the truck and took four quick photos with my I-phone before the second light switched off. I grabbed my 7x50 binoculars and scanned the area where I have seen the lights and could not see any flashing or blinking lights that might have indicated a conventional aircraft. The lights never got higher than 10-15 degrees above the ridgeline.About 10-15 minutes later a third light appeared off to my right, in the northeast, that I observed through the drivers side window. This light was much larger and much closer, and moving west about 50 degrees high in the sky. I estimate it was only 3-4 miles away, and I watched it for about 15-20 seconds and started to get out of the truck to take photos of this object when, like the other two, it suddenly switched off. There was a bright moon this night and the sky was completely clear in this area. There were no blinking lights to indicate a conventional aircraft of any type.Some minutes later a 4th light appeared again to the east where I had seen the first two, and this too ascended and blinked out after about 20-30 seconds. I have been watching the skies out here for 33 years and been in MUFON for 15 years and believe these were UFOs/alien craft.I cropped the photos before sending them to you. As you can see there are no other lights, such as an aircraft must display, seen in the photos.