Trip report for O'Melveny Park - Granada Hills Sunday, March 29, 2015 

We had some nice birds on this O'Melveny walk, with California Quail making the list before the walk even started. Many species were in full song, marking their territories and attracting mates.  House Wrens definitely dominated birdsong in the park, but the most interesting call we picked-up right away was Least Bell's Vireo.   We saw no less than three of these federally protected birds!  Listed as an endangered species, this subspecies of the Bell's Vireo has been on the brink of extinction and back in recent decades, with the main pressure coming from habitat destruction from urban development.  Remaining riparian habitat is essential for Least Bell's Vireo recovery, including some of the areas that the Army Corps of Engineers love to mow down in the Sepulveda Basin.  I guess the Federal Government has a pass with these things...

At the very end of the walk, we had both Cassin's and Western Kingbirds.  These two birds are similar in appearance and there was discussion on how to tell the difference between them. The easy way for me is, when looking from underneath the Cassin's Kingbird's chest and head is a darker gray than the Western.  Although this difference is not easy to see, it does create the appearance of the Cassin's having a whitish throat.  Another distinctive difference is that Cassin's has a thin white strip along lower edge of the tail feathers and Western has a thin white strip that runs along the edge of the tail feathers.  Caveats to these tail markings: they can sometimes be hard to see because of harsh lighting and/or feather condition (as in the photo of the Cassin's below).  Some birds just aren't easy!!