recent birding at Cosumnes, including least flycatcher and black-and-white warbler

Glennah Trochet

Dear Birders,

I have enjoyed a long Labor Day weekend of seeking birds at the Cosumnes River Preserve in southern Sacramento County.  Beginning Thursday, I visited daily.  Excepting Saturday, I started each morning behind the Farm Center gate and did a mix of woodland birding and walking ditch banks and field margins, the route a bit different each day.  On Saturday I did the monthly Lost Slough bird survey on the parcel west of Franklin Boulevard.  Morning lows were 38 degrees both Thursday and Friday, warming a bit daily thereafter.  It was still a pleasant 44 degrees this morning.

The finds of at least personal interest from Thursday:
black-chinned hummingbird-  1
sharp-shinned hawk-  1
western wood-pewee-  3
willow flycatcher-  2
warbling vireo-  3
Hutton's vireo-  2 (breaking a streak of about five visits missing it)
orange-crowned warbler-  3
common yellowthroat-  7
yellow warbler-  2
black-throated gray warbler-  1
Wilson's warbler-  8
western tanager-  6
blue grosbeak-  1

On Friday the 3rd of September, the finds included the unexpected treat of a black-and-white warbler in the Tall Forest:
acorn woodpecker-  2
Pacific-slope flycatcher-  1
western flycatcher-  2
warbling vireo-  1
Hutton's vireo-  missed again
possible bank swallow- the only swallow I saw was flying away from me.  It was snowy white on the belly and vent and dorsally the wings and tail upper surfaces were darker than the contrastingly paler back and rump.  But I never saw the breast. let alone the breast band.
ruby-crowned kinglet-  1 (I would have said early except that Ed Pandolfino and Debbie Shearwater had their firsts of the season three weeks ago!)
blue-gray gnatcatcher-  1
Swainson's thrush-  2 (nocturnal flight calls around dawn)
cedar waxwing-  3 (my FOS)
black-and white warbler-  1 (first fall female by plumage)
orange-crowned warbler-  2
MacGillivray's warbler-  2
common yellowthroat-  9
yellow warbler-  8
Wilson's warbler-  18
western tanager-  9
lazuli bunting-  1

On Saturday's survey I expected, wrongly, to find no water, so I didn't tote my scope around.  But I ran into Andrew Lee birding with his brother at the pond west of the Visitor Center overlooked by the low wooden deck.  Andrew told me that this pond was being flooded up the previous weekend, so there was enough time to get the start of an invertebrate bloom.  There were waterfowl and shorebirds present.  The days highlights included the following:
sandhill crane-  1 (my FOS, in flight heading SW, possibly to Staten Island)
lesser yellowlegs-  1 (Andrew Lee kindly showed me one in his scope)
willow flycatcher-  1
western flycatcher-  2
loggerhead shrike-  2
horned lark-  1 (FOS, a fly over)
white-crowned sparrow-  1 (FOS, a hatch year bird)
orange-crowned warbler-  1
common yellowthroat-  2
yellow warbler-  6
black-throated gray warbler-  2
Wilson's warbler-  2

On Sunday the 5th, in ideal conditions, birding was very slow.  Approximately four miles of birding in prime habitat produced zero bushtits.  I can't recall getting skunked in and around the Tall Forest before.  A long morning produced only these migrants:
western flycatcher-  1
Lincoln's sparrow-  1 (FOS)
orange-crowned warbler-  1
MacGillivray's warbler-  1
common yellowthroat-  8
yellow warbler-  4
black-throated gray warbler-  1
Wilson's warbler-  3
western tanager-  8

Perhaps the lowlight today was the uninvited company of the neighbor's two large dogs for 2/3 of a mile of my route.  Their nearly constant barking and snarling while tussling with one another coincided with a particularly quiet birding experience of what is usually a productive edge.  But after we parted company things picked up a lot.  But again in late morning, birding was very slow, and I can't blame the dogs for that.  The highlight was a vocal least flycatcher, seen with willow flycatcher immediately adjacent and western flycatcher nearby.  Today's birds of interest:
black-chinned hummingbird-  1
western wood-pewee-  4
willow flycatcher-  5
least flycatcher-  1
Pacific-slope flycatcher-  3
western flycatcher-  6
Empidonax sp.-  3
warbling vireo-  1
yellow-headed blackbird-  1 (FOS; I know, I'm well behind on this one)
orange-crowned warbler-  5
common yellowthroat-  22
yellow warbler-  19
Audubon's warbler-  1 (FOS, in lerpy eucs at the Love Shack)
Wilson's warbler-  4
western tanager-  4
blue grosbeak-  3

For numbers, the most remarkable species the last couple of months has been oak titmouse.  Perhaps the local population has developed much better immunity to West Nile since that plague appeared locally in 2005.  But it might not be due to improved immunity.  It might be the paucity of vectors this year.  2021 is, hands down, the least troublesome year with respect to mosquitoes since I came on board at Cosumnes in 1994.  I would be interested to know the experience of others regarding the recovery (or lack of it) of titmouse numbers since they crashed about 15 years ago.

John Trochet