I think flies in general around water areas are in abundance this year because of all the rain. On some hikes this last month into Granite Mountains near our home I ran into alot of flies around the spring areas, and many while hiking too. Not biting flies, but a nusiance none the less. Today I was out for a hike in these same areas and there were much fewer flies so hopefully they are dying off now that things are getting warmer. I know earlier in the spring at our home here in Apple Valley there was a deluge of various flying insects from the rains, and now they are gone thankfully. Our swimming pool was full of these little bee like insects that were attracted to the water, and our garage window was full of dead big flying insects that look like huge Mosquito's, these ones don't bite but where flying all around the patio during the day, and where gathering by any light's at night in swarms. I talked to the neighbors and they said they had not seen anything like that before in the spring. I think summers heat will bring things back into balance again, and thats fine with me :-)