Photo 2676656, (c) Liam O'Brien, some rights reserved (CC BY-NC), uploaded by Liam O'Brien

Attribution © Liam O'Brien
some rights reserved
Uploaded by robberfly robberfly
Source iNaturalist
Associated observations

Photos / Sounds


Monarch (Danaus plexippus)




November 19, 2015 12:38 PM PST


I returned from the Texas this week straight into my annual commitment to survey the Western Migration/Overwintering Sites of the Monarch ( Danaus plexxipus ) in San Francisco County.
With Mr. Adolph Sutro's "gift " of Blue Gum Eucalyptus to our city more than 100 years ago, this is a great deal more difficult than it sounds - complete "needle in haystack " work for three weeks and, to be honest, not I've done this now for 8 years and we have so few Monarchs that a real Natural Bridges-them-flying-everywhere-in-the-canopy is something I never see. Dr. John Hafernik reported 700 in Golden Gate Park in 1997. I've never seen anything coming close to that at any historic site I visit...
Until today...
Reports had come in from the staff at the Presidio Trust of "dozens and dozens" in certain areas. Took two buses and climbed up the known north-facing wall of Rob Hill, a historic roost that had been radically altered due to restoration for the endangered San Francisco Lessinga ( Lessingia germanium ). The Presidio Trust has been working with Dr. Stuart Weiss to protect the known habitat for the Monarchs while drastically thinning the north-facing wall of Eucs. I walked to the far eastern portion of the Hill and...there they were. Numbers I've never seen it San Francisco. Most of them sunning themselves. Nothing much to nectar on but...clearly a healthy roost.
Counted approximately 225 - the most I've ever seen in our county in one day.
Not really interested in the never-ending politics of this creature - what are we doing right/what are we doing wrong - just...reveled in it's...phenomenon today.

Associated taxa