I had an interesting morning's birding at the Botanic Garden today. In general, I did not find an abundance of migrants or summer visitors, but there were a couple of interesting pockets and in one of them, I had a Vireo that I strongly suspect was a Plumbeous Vireo. I know spring sightings of this species in our county are very unusual, but here's what I saw:
A "solitary" type Vireo with a gray head, white spectacles, white underparts, dark wings with two white wing bars, and what appeared to be a gray back. The latter feature was never seen clearly as I was looking at the bird from below most of the time and when I glimpsed the back, it was through oak leaves. There was no trace of green or yellow on any of the underparts, which I saw very well for several minutes.
The Vireo was feeding with a small warbler group in a coast live oak on the lower part of the Pritchett Trail above the Campbell Bridge. I have found in the past that this is a good place to look for migrants in that the birds are mostly at eye level. After a few minutes, it flew back along the way I had come and started to sing frequently. I had to double back along the trail loops to where it was singing and though I could spot it moving around in another oak tree, it was never really in view again.
Eventually it stopped singing and I finally lost track of it. But I was able to compare the song I was hearing with the Plumbeous Vireo call on Birds of North America and they sounded very much the same--definitely more like Plumbeous than the Cassin's song on the same device.
Other notes: In the same group where I found the Vireo, I also had a Black-throated Gray Warbler, Wilson's Warbler, several Yellow-rumps, and an Orange-crowned Warbler. A Black-headed Grosbeak sang briefly from Tunnel Road above. Below the East Slope of the Garden, I found an Ash-throated Flycatcher and a singing Nashville Warbler in the trees along Pedregosa Creek. Sadly, though the Garden is in beautiful bloom right now, I could turn up only Anna's Hummingbirds this morning, but this will be a spot to continue to check for other species.