Swainson’s Hawks are back in California. I just encountered a mating pair in the city of Brentwood right next to the field where a few pairs of Burrowing Owls are nesting (see previous post on 4/7/15). It’s a treat to see these majestic raptors come back every year considering they just flew roughly 10,000 Km all the way from South America (most likely Argentina).

 Not surprisingly, I found them on a large vacant lot where hay has just been cleared, and therefore, blown the cover for a colony of at least 2,000 ground squirrels. Swainson’s have adapted to live around people (here and in Argentina) and often follow farm and field disturbance activities to make the most of their hunting efforts. In this case, an unlimited supply of ground squirrels with no vegetation to hide from aerial survei...

Last week I went to see the carcass of a sperm whale bull that washed ashore at  Mori Point in Pacifica. I had mixed feelings about this. It’s heart breaking to see such a magnificent beast just laying there on the beach. On the other hand, it is an exciting opportunity to see a sperm whale carcass up close (or what was left of it after the necropsy).

 As far as I know the cause of death is not know yet. What we know is that it looked emaciated and possibly presented signs of trauma. One likely possibility is a collision with a ship, particularly along the west coast where ship traffic is heavy around major ports like Oakland/San Francisco and L.A. Ship strikes are not the only threat. The last sperm whale carcass found in Northern California showed up in Point Reyes in 2008. The...

One of the joys of being a naturalist is finding the unexpected. That just happened to me as I was driving around Brentwood, CA and saw a pair of burrowing owls. It is a reminder of how adaptable and at the same time fragile is the wildlife that live in and around our sprawling urban areas.

The owls were standing on the sidewalk next to their burrow at the edge of a vacant lot. In the absence of enough grasslands and other natural habitats, disturbed areas and vacant lots have become prime habitat for burrowing owls.

Burrowing owls in California chose sites with available burrows often made by ground squirrels.

The pair was not alone, I counted a total of at least 4 pairs as I scanned the area. The unexpected today is not only that I found burrowing owls, but a smal...

There's alot going on at Berkeley's Regional Botanical Gardens. Trilliums and wallflowers are blooming and trees are beginning to leaf out. Spring has already begun around here. A week ago, park staff directed me to a stunning ceanothus silk moth (Hyalophora euryalus)  who've just came out of its cocoon and was holding on motionless on ...yes, a ceanothus branch. The short antenna immediately gave her away as a female (males have noticeably larger antenna) and the large abdomen was a sure sign she was gravid and filled with eggs. Ceanothus silk moths are active at night and lay motionless during the day. In the early morning hours females release a chemical to attract males.

I visited the gardens again last Friday to join Alan Kaplan's Golden Gate Audubon monthly walk. The s...