Date: 1/14/25 9:41 am From: Chris Conard via groups.io <conardc...> Subject: [centralvalleybirds] Bufferlands portion of the Rio Cosumnes CBC on 2 Jan 2025
Hi folks,
Many thanks to new compiler, Zane Pickus, for keeping the Rio Cosumnes CBC
going and to Andy Engilis for getting it going 30 years ago!!
I prepare a summary for Bufferlands voluteers and staff and thought this
might be of wider interest.
On Thursday, January 2, 2025, a total of 17 counters, made up of
Bufferlands staff and volunteers, participated in the 29th annual Rio
Cosumnes Christmas Bird Count (CBC). The weather was about perfect for this
time of year. It was between 43-60F, sunny all day, with periods of thin
clouds filtering the sun, and there was only a light breeze. We had five
teams in the field and good access except for flooding at Upper Beach Lake
(water level at ~3.4 ft above sea level with an attenuated connection to
the waters of the Delta). The Bufferlands and the EchoWater Facility
(formerly the Sacramento Regional Wastewater Treatment Plant) it surrounds
is at the northwestern portion of the 15-mile diameter CBC circle that
includes Cosumnes River Preserve, Stone Lakes National Wildlife Refuge,
western Elk Grove, northwestern Galt, and a portion of Merritt Island in
Yolo County.
We recorded 107 species on the Bufferlands, within a historical range of 90
to 120, and counted 27,842 individual birds, within a historical range of
7,723 to 811,644. This year we added a new species (Blue-gray Gnatcatcher <
https://ebird.org/checklist/S207680674>) to our cumulative total, now at
166 species, recorded on the Bufferlands portion of the count in 29 years.
Oddly, the number of individual birds is a couple hundred more than the
Folsom CBC recorded. As impressive as that is, ~10,000 were starlings and,
even worse, 2,000 were cowbirds at the Bufferlands/WTP.
Starting with waterfowl, numbers and diversity were below average. We did
well with geese and swans, including 32 flyover Snow Geese, three Ross’s
(recorded for just the fifth time), and 1493 Greater White-fronted Geese,
many not just flyovers, but apparently spending the night on the property.
We missed Cackling Geese, had 316 Canada Geese, and 21 flyover Tundra
Swans. We found four invasive Mute Swans just like last year. Duck numbers
and diversity were disappointing. We missed Canvasback, one of our mascot
species, for the just the second time—but for the second time in a row,
completely missing the species on the Bufferlands in 2024. We had only 143
Ring-necked Ducks and one Ruddy Duck. Dabbling duck numbers were also on
the low side and with no surprises. And we found 14 Hooded Mergansers and
two Common Mergansers; the latter we have missed more often than not in
recent years, while Hoodies have become a staple since 2006.
Two Wild Turkeys found in 2003 were the first recorded on our portion of
the count, but they have rapidly increased, continuing at high levels this
year with an impressive 376 [more than double what were recorded on the
whole Folsom CBC, where they seem to be declining]—our highest count was
487 in 2019. Ring-necked Pheasants remain at very low numbers, in keeping
with regional declines, and we found only two. Prior to 2003, we expected
at least 100 on count day. We found 20 California Quail—a species that can
be missed. We have a lot of Mourning Doves, and recorded 537, as well as
four Eurasian Collared-Doves.
A single Virginia Rail and two Soras were detected. We missed and no longer
expect to find Common Gallinules on the property. We would record over 100
in the 1990s, 33 as recently as 2005, but no more than one since 2012.
Sandhill Cranes have become regular for more than a decade, and this time
we recorded 132, doing our best to avoid double-counting with flyover
birds, birds on the ground, and five parties counting in the field.
Among shorebirds, the highlight was an impressive 12 Spotted Sandpipers all
in the SSBs (sewer ponds)—in ones and twos all over the SSBs. A single
Western Sandpiper was an excellent find of a species recorded for just the
fifth time, but for the fourth year in a row. Two Dunlin were around
earlier in the week, but we missed them on count day. We also missed
Black-bellied Plovers as we have every year since 2010; gone are the days
when we could find up to 1,000 roosting in the SSBs on sunny afternoons.
Great Egrets and Great Blue Herons were in good numbers, and an American
Bittern was the last new bird of the day.
While there is a slight tone of disappointment to much of what has been
written above, raptor numbers were very good. Sunny days are often good for
raptors, but we have also been seeing good numbers this fall and winter. We
recorded a Swainson’s Hawk < https://ebird.org/checklist/S207752670> on the
Bufferlands portion of the count for just the fifth time, and for the first
time in many years. White-tailed Kites, at 11, and Northern Harriers, at
16, rebounded from last year’s near-record lows. At 56, we had the best
Red-tailed Hawk count since 2007. After what appeared to be a good breeding
season, we found only two Barn Owls. Seven Great Horned Owls was about
average, while seven Burrowing Owls was our second best total since the
1990s. We found 23 American Kestrels (slightly above average), and two
Merlins, but missed both of the larger falcon species.
Yellow-billed Magpies and Loggerhead Shrikes have declined since 2005 when
West Nile virus arrived in our area, and we found 20 magpies and just one
shrike. Western Bluebirds have only been regular on the property since 2014
and we recorded 38. We nearly missed American Robin, finding one late in
the day, but did miss Varied Thrush—a species with highly variable local
abundance. We eked out two Golden-crowned Kinglets—both singles among
different Bushtit flocks, which were above average at 281. Ruby-crowned
Kinglets were slightly above average at 105. Sparrow numbers were mostly
below average, with Savannah Sparrows rebounding to 152 after last year’s
dismal 42. White-crowneds, at 293, were a little thin, but Golden-crowned
Sparrows, at 68, were well under half of their historical average. Song
Sparrows, at 20, Lincoln’s Sparrow’s, at 9, and Fox Sparrows, at 6, were
also well under half of their historical averages. California Towhees, once
only found along a remnant railroad levee west of I-5, are becoming more
widely established on the property. Five individuals accounted for three
locations, two of which are fairly new. We couldn’t find the Townsend’s
Warbler seen on New Year’s Eve, but did have seven Orange-crowned Warblers.
Myrtle Yellow-rumped Warblers, at only five, were way down along the
poison-oak-berry-laden Laguna Creek, where they are sometimes found in the
dozens. Audubon’s Yellow-rumpeds were reasonably abundant.
Our results provide a snapshot of the winter bird population, within the
context of several ongoing trends. Some of these trends reflect changes in
abundance of individual species, but more reflect wider habitat
relationships affecting suites of species with categories such as
“grassland birds” or “marsh birds.” Although any one day’s results can be
over-interpreted, this CBC’s findings are generally consistent with
regional trends, changes in local land use, or maturing of habitats on the
Bufferlands itself.
