[EBB Sightings] changing population

Dear Birders:

As the old decade ends, and the new one begins, I reflect on the changes in local bird populations.  I've been keeping some sort of records over the almost six decades I've lived here in the Berkeley Hills.  Though my observations are local -- my feeders, garden, and frequent walks in Strawberry Canyon and in Tilden Park -- I have noticed some significant changes.

In the last decade, I have observed a decline in the winter sparrow flocks.  Once, I had mixed flocks of Golden-crowned and White-crowned Sparrows, and a regular Fox Sparrow, along with resident and wintering Dark-eyed Juncos at my feeders.  For the last two years I have no Fox Sparrows and the Juncos outnumber the sparrows about 10 to 1.

At the same time, I have large year-round flocks of mostly Lesser Goldfinches who crowd the feeders (they were in small numbers 10 years ago).  Arboreal birds such as Chestnut-backed Chickadees, Red-breasted Nuthatches maintain good numbers (along with the recent visits of Pygmy Nuthatches which are now more numerous).  Populations of both jays, California Towhees, and Mourning Doves remain fairly constant. 

But long-gone from the neighborhood are coveys of California Quail. Turkeys are a new resident.  Yellow-rumped Warblers are more abundant.  Cedar Waxwings and Pine Siskins have always been highly variable from year to year.

Though my range of observation is limited, I observe that some raptors are more abundant (Cooper's Hawks are becoming 'urban') but I seldom see an American Kestrel these days.

I would like to hear from other bird observers in the greater Bay Area who have observed, or recorded changes, in their local bird populations over the years.

It's a fascinating business full of "whys."  My immediate habitat has changed little, except for the maturing of certain planted trees, as I live in developed neighborhood adjacent to mostly unchanged park lands.  The decline in wintering sparrows prompts me to wonder if there are significant changes in their northern breeding grounds to explain their local decline, or is it climate change?

I will make an attempt to organize the responses.

Thanks and a happy new year to all.

-Phila Rogers