Hundreds of extra large bees were gathered in groups, mostly near the shoreline
"The genus Centris contains circa 250 species of large apid bees occurring in the Neotropical and Nearctic regions, from Kansas to Argentina. Most females of these bees possess adaptations for carrying floral oils rather than (or in addition to) pollen or nectar. They visit mainly plants of the family Malpighiaceae to collect oil, but also Plantaginaceae, Calceolariaceae, Krameriaceae and others."
Amazing nesting aggregation of Ptilothrix chiricahua with females visiting cattle tank for water.
Family guess is a iNat suggestion. Thanks for ID help! Hundreds, if not a thousand, individuals flying over the ground and digging on embankment of patchy grass on golf course. Holes the size of a pencil diameter. Bees the size of pointer fingernail.
A dead bee measured 1cm long.
Large mining bee aggregation along the golf course 7th green. Small, 1cm.
I have observed nest holes in this area for several years. I cannot post videos here, so have loaded three short ones of a bee at its nest hole and general view of the communal nesting on my You-tube channel.
Short video of bee over nest site: https://youtu.be/MBQ6wcsASYY
Long video of bee over nest site: https://youtu.be/2U1prHigDWA
View of communal ground nesting site: https://youtu.be/dOQnmJ1ieq4
This is an update for observation https://www.inaturalist.org/observations/71833402
Bee photographs taken by AE Hass, with permission given to post on my observation. https://www.inaturalist.org/people/edhass
Individual bees photographed at the aggregation will be listed in separate observations. Location and nest hole photographs will be repeated across the observations because two different diameter holes were observed. Note the difference in clay color. Without looking at the prior observation notes, we felt the aggregation numbered approximately 1000 nests. A map with dimensions of the site is included. The slope faces south / southwest.
This is an update for observation https://www.inaturalist.org/observations/71833402
Bee photographs taken by AE Hass, with permission given to post on my observation. https://www.inaturalist.org/people/edhass
Individual bees photographed at the aggregation will be listed in separate observations. Location and nest hole photographs will be repeated across the observations because two different diameter holes were observed. Note the difference in clay color. Without looking at the prior observation notes, we felt the aggregation numbered approximately 1000 nests. A map with dimensions of the site is included. The slope faces south / southwest.
This is an update for observation https://www.inaturalist.org/observations/71833402
Bee photographs taken by AE Hass, with permission given to post on my observation. https://www.inaturalist.org/people/edhass
Individual bees photographed at the aggregation will be listed in separate observations. Location and nest hole photographs will be repeated across the observations because two different diameter holes were observed. Note the difference in clay color. Without looking at the prior observation notes, we felt the aggregation numbered approximately 1000 nests. A map with dimensions of the site is included. The slope faces south / southwest.
Bee photograph taken by AE Hass, with permission given to post on my observation. https://www.inaturalist.org/people/edhass
Individual bees photographed at the aggregation will be listed in separate observations. Location and nest hole photographs will be repeated across the observations. We felt the aggregation numbered approximately 3000 nests. A map with dimensions of the site is included. Many of the nests are beneath mature oak trees but the edge of hillside slopes west / southwest.
Bee photograph taken by AE Hass, with permission given to post on my observation. https://www.inaturalist.org/people/edhass
Individual bees photographed at the aggregation will be listed in separate observations. Location and nest hole photographs will be repeated across the observations. We felt the aggregation numbered approximately 3000 nests. A map with dimensions of the site is included. Many of the nests are beneath mature oak trees but the edge of hillside slopes west / southwest.
Bee photograph taken by AE Hass, with permission given to post on my observation. https://www.inaturalist.org/people/edhass
Individual bees photographed at the aggregation will be listed in separate observations. Location and nest hole photographs will be repeated across the observations. We felt the aggregation numbered approximately 3000 nests. A map with dimensions of the site is included. Many of the nests are beneath mature oak trees but the edge of hillside slopes west / southwest.
Bee photograph taken by AE Hass, with permission given to post on my observation. https://www.inaturalist.org/people/edhass
Individual bees photographed at the aggregation will be listed in separate observations. Location and nest hole photographs will be repeated across the observations. We felt the aggregation numbered approximately 3000 nests. A map with dimensions of the site is included. Many of the nests are beneath mature oak trees but the edge of hillside slopes west / southwest.
Bee photograph taken by me.
Individual bees photographed at the aggregation will be listed in separate observations. Location and nest hole photographs will be repeated across the observations. We felt the aggregation numbered approximately 3000 nests. A map with dimensions of the site is included. Many of the nests are beneath mature oak trees but the edge of hillside slopes west / southwest.
3 separate tumulus piles, the one in photo has 3 entrances. I have seen up to 3 females exit each entrance. About 1/4 cup of soil in the pile around the entrance. Clay soil, vegetation mown about 4 inches. Forages on Geum macrophyllum, dandelions, camas
Flying in and out of tiny raised sand piles with exit hole. More than one bee per hole.