Tuesday, October 08, 2013

Hermit Thrush Arrives Early in Southern California

For the past 12 years I have been documenting the birds that daily frequent our yard, the migratory birds that travel through and the species that visit during a specific season. The hermit thrush (Catharus guttatus) is one of my favorites. On the small side, this bird typically arrives alone or with a single companion. It stands with its head raised like an American robin, but it is slighter in size has brown spots on a white chest, a gray-brown back and a russet tail. Spending the winter here in southern California, the hermit thrush is shy and elusive. By the time I spot it, there is no chance to grab the camera. It slips in and out of the shrubs, plucking a toyon berry or any of the variety of reddish round berries on the vegetation.

The only vocalizations are typically soft chirps in the early morning. (Imagine my surprise this summer in Alaska when I heard this beautiful singing bird and it turned out to be my quiet friend. In its breeding grounds, the hermit thrush is known as the songster of the forest.)

Another surprise was that this year the hermit thrush arrived on October 4th. It seemed early and it was. I graphed the arrival dates for the hermit thrush that I have recorded annually since 2001. The vertical axis shows dates with numerical values (November 15 = 11.5).

It's a graphic demonstration of gradual change. The arrival date of the hermit thrush varied dramatically in the first years of the century, fluctuating between mid-October and mid-November. However since 2007 the hermit thrush has been arriving in October. This year was the earliest date I've recorded. 

This corresponds somewhat with our rainfall levels. Since 2007, we have not had the dramatic years of heavy rainfall that we used to have. Another interesting aspect is where did this hermit thrush come from? Did it leave its summer breeding grounds early because of a factor in that far away place?  Is it a different individual bird?

Other migratory birds are passing through and arriving. Last Week. This weekend a female black-throated gray warbler stopped to rest and hunt for insects in the elm tree.

The white-crown sparrows arrived somewhat early too. Interestingly the snowbirds that usually arrive first in our yard are the Oregon juncos, and they have yet to show up. They had been arriving earlier and earlier each September. I wonder what their story is?

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